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	<title>潘锦的空间 &#187; xml解析</title>
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		<title>XML解析中DOM和SAX的比较和选择</title>
		<link>https://www.phppan.com/2011/03/xml-parse-dom-sax/</link>
		<comments>https://www.phppan.com/2011/03/xml-parse-dom-sax/#comments</comments>
		<pubDate>Mon, 28 Mar 2011 01:00:50 +0000</pubDate>
		<dc:creator><![CDATA[admin]]></dc:creator>
				<category><![CDATA[PHP]]></category>
		<category><![CDATA[DOM]]></category>
		<category><![CDATA[SAX]]></category>
		<category><![CDATA[xml解析]]></category>

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		<description><![CDATA[在前面的文章 &#60;&#60;PHP中的XML解析的5种方法&#62;&#62; 中以功能实现为维度实现了XML的 [&#8230;]]]></description>
				<content:encoded><![CDATA[<p style="text-indent: 2em;">在前面的文章 <a style="color: #1299da; text-decoration: underline;" href="http://www.phppan.com/2009/10/phps-five-methods-of-xml-parseing/">&lt;&lt;PHP中的XML解析的5种方法&gt;&gt;</a> 中以功能实现为维度实现了XML的解析。 今天我们从另外的维度说说XML解析的两种方式。 一般来说，在PHP中，XML的解析包括DOM，SAX，正则表达式等常规方式。 特别是前面的两种，不管是在PHP中还是在Java等语言中都有使用。</p>
<h2 style="font-weight: bold; font-family: 'Microsoft YaHei', Helvetica, Arial, sans-serif; font-size: 1.2em; color: #333333;">DOM解析器</h2>
<p style="text-indent: 2em;">DOM 是具有平台和语言无关性。它是表示 XML 文档的官方 W3C 标准。 DOM解析器在实现方式是预加载整个文档，并把XML文档转化为一个包含其内容的树。 这个树结构方便开发人员在其中寻找特定信息，并可以调用树的一些操作很容易的添加和修改树中的元素。</p>
<p style="text-indent: 2em;">在PHP中，它在形式上是基于对象的存储，然而在本质上是存储在一堆结构体中， 在对象与对象的之间是以一种类似于父子的概念关系存在，从而在整体上构成了一个树的结构。</p>
<p style="text-indent: 2em;">由于DOM解析器是预加载的，所以整个文档的结构在内存中是持久存在的。因此可以在其生命周期中随时修改它，以便应用程序能对数据和结构作出更改。 它还可以在任何时候在整个树结构中上下导航，并且DOM解析器使用起来比较简单。 但是，同样因为是预加载的方式，需要处理整个 XML 文档，所以对性能和内存的要求比较高。 当遇到特别大的文档时，解析和加载整个文档可能会很慢且很耗资源， 此时我们就需要另外一种方式，比如一边读取一边处理，又或者类似于SAX基于事件的模型。</p>
<p style="text-indent: 2em;">在PHP中使用DOM解析器是基于DOMDocument类来实现。具体的实现请移步之前的文章： <a style="color: #1299da; text-decoration: underline;" href="http://www.phppan.com/2009/10/phps-five-methods-of-xml-parseing/">&lt;&lt;PHP中的XML解析的5种方法&gt;&gt;</a></p>
<h2 style="font-weight: bold; font-family: 'Microsoft YaHei', Helvetica, Arial, sans-serif; font-size: 1.2em; color: #333333;">SAX解析器</h2>
<p style="text-indent: 2em;">SAX是simple API for XML的简写，与DOM不同，它并不进行预加载操作，而是一边扫描文档，一边解析。 SAX解析器 采用了基于事件的模型，它在解析 XML 文档的时候可以触发一系列的事件， 当发现给定的tag的时候，它可以激活一个回调函数，告诉该函数指定的标签已经找到。 SAX解析器 对内存的要求通常会比较低，因为它让开发人员自己来决定所要处理的tag。 特别是当开发人员只需要处理文档中所包含的部分数据时，SAX解析器 这种扩展能力得到了更好的体现。 但用 SAX 解析器的时候编码工作会比较困难，而且很难同时访问同一个文档中的多处不同数据。 　　 看一个PHP中使用SAX解析器的例子。我们使用Google天气API的XML文档。</p>
<p style="text-indent: 2em;">API地址：http://www.google.com/ig/api?weather=shenzhen</p>
<pre style="background-color: #333333; color: #ffffff; font: normal normal normal 13px/normal 'Bitstream Vera Sans Mono', 'DejaVu Sans Mono', 'Courier New', monospace; overflow-x: auto; overflow-y: auto; padding: 10px;"><span style="color: #cc7833;">&lt;?php</span>
<span style="color: #cccccc; font-style: italic;">/**
 * 简单的Google天气SAX解析器
 * 解析http://www.google.com/ig/api?weather=shenzhen中将来几天的天所情况
 */</span>
<span style="color: #cc7833;">class</span> weatherSaxParser <span style="color: #ffffff;">{</span>

    <span style="color: #cc7833;">private</span> <span style="color: #6d9cbe;">$_parser</span><span style="color: #e0882f;">;</span>
    <span style="color: #cc7833;">private</span> <span style="color: #6d9cbe;">$_xmlData</span><span style="color: #e0882f;">;</span>
    <span style="color: #cccccc; font-style: italic;">/**
     * 当前的Tag
     * @var &lt;type&gt;
     */</span>
    <span style="color: #cc7833;">private</span> <span style="color: #6d9cbe;">$_tag</span><span style="color: #e0882f;">;</span>
    <span style="color: #cc7833;">private</span> <span style="color: #6d9cbe;">$_weather</span><span style="color: #e0882f;">;</span>
    <span style="color: #cccccc; font-style: italic;">/**
     * 保存天气的数组的key
     * @var &lt;type&gt;
     */</span>
    <span style="color: #cc7833;">private</span> <span style="color: #6d9cbe;">$_key</span><span style="color: #e0882f;">;</span>
    <span style="color: #cc7833;">private</span> <span style="color: #6d9cbe;">$_attributes</span><span style="color: #e0882f;">;</span>
    <span style="color: #cccccc; font-style: italic;">/**
     *需要解析的标签集合
     * @var &lt;type&gt;
     */</span>
    <span style="color: #cc7833;">private</span> <span style="color: #6d9cbe;">$_parseTags</span> <span style="color: #e0882f;">=</span> <a style="color: #1299da; text-decoration: none;" href="http://www.php.net/array"><span style="color: #e2392d;">array</span></a><span style="color: #ffffff;">(</span><span style="color: #56db3a;">'low'</span><span style="color: #e0882f;">,</span> <span style="color: #56db3a;">'day_of_week'</span><span style="color: #e0882f;">,</span> <span style="color: #56db3a;">'high'</span><span style="color: #e0882f;">,</span> <span style="color: #56db3a;">'condition'</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>

    <span style="color: #cc7833;">public</span> <span style="color: #cc7833;">function</span> __construct<span style="color: #ffffff;">(</span><span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>
        <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_key <span style="color: #e0882f;">=</span> <span style="color: #1299da;">0</span><span style="color: #e0882f;">;</span>
        <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_parser <span style="color: #e0882f;">=</span> <a style="color: #1299da; text-decoration: none;" href="http://www.php.net/xml_parser_create"><span style="color: #e2392d;">xml_parser_create</span></a><span style="color: #ffffff;">(</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>

        <a style="color: #1299da; text-decoration: none;" href="http://www.php.net/xml_set_object"><span style="color: #e2392d;">xml_set_object</span></a><span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_parser<span style="color: #e0882f;">,</span> <span style="color: #6d9cbe;">$this</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>
        <a style="color: #1299da; text-decoration: none;" href="http://www.php.net/xml_set_element_handler"><span style="color: #e2392d;">xml_set_element_handler</span></a><span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_parser<span style="color: #e0882f;">,</span> <span style="color: #56db3a;">'tagStart'</span><span style="color: #e0882f;">,</span> <span style="color: #56db3a;">'tagEnd'</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>
        <a style="color: #1299da; text-decoration: none;" href="http://www.php.net/xml_set_character_data_handler"><span style="color: #e2392d;">xml_set_character_data_handler</span></a><span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_parser<span style="color: #e0882f;">,</span> <span style="color: #56db3a;">'tagContent'</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>
    <span style="color: #ffffff;">}</span>

    <span style="color: #cc7833;">public</span> <span style="color: #cc7833;">function</span> setXmlData<span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$xml</span><span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>
        <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_xmlData <span style="color: #e0882f;">=</span> <span style="color: #6d9cbe;">$xml</span><span style="color: #e0882f;">;</span>
    <span style="color: #ffffff;">}</span>

    <span style="color: #cccccc; font-style: italic;">/**
     * 执行解析操作
     */</span>
    <span style="color: #cc7833;">public</span> <span style="color: #cc7833;">function</span> run<span style="color: #ffffff;">(</span><span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>
        <a style="color: #1299da; text-decoration: none;" href="http://www.php.net/xml_parse"><span style="color: #e2392d;">xml_parse</span></a><span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_parser<span style="color: #e0882f;">,</span> <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_xmlData<span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>
    <span style="color: #ffffff;">}</span>

    <span style="color: #cccccc; font-style: italic;">/**
     * 标签开始回调函数
     * @param &lt;type&gt; $parser
     * @param &lt;type&gt; $tagName
     * @param &lt;type&gt; $attributes
     */</span>
    <span style="color: #cc7833;">public</span> <span style="color: #cc7833;">function</span> tagStart<span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$parser</span><span style="color: #e0882f;">,</span> <span style="color: #6d9cbe;">$tagName</span><span style="color: #e0882f;">,</span> <span style="color: #6d9cbe;">$attributes</span> <span style="color: #e0882f;">=</span> <span style="color: #cc7833;">NULL</span> <span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>
        <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_tag <span style="color: #e0882f;">=</span> <a style="color: #1299da; text-decoration: none;" href="http://www.php.net/strtolower"><span style="color: #e2392d;">strtolower</span></a><span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$tagName</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>
        <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_attributes <span style="color: #e0882f;">=</span> <span style="color: #6d9cbe;">$attributes</span><span style="color: #e0882f;">;</span>

        <span style="color: #ff8400;">if</span> <span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_tag <span style="color: #e0882f;">==</span> <span style="color: #56db3a;">'forecast_conditions'</span><span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>
            <span style="color: #6d9cbe;">$item</span> <span style="color: #e0882f;">=</span> <a style="color: #1299da; text-decoration: none;" href="http://www.php.net/array"><span style="color: #e2392d;">array</span></a><span style="color: #ffffff;">(</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>
            <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_weather<span style="color: #ffffff;">[</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_key<span style="color: #ffffff;">]</span> <span style="color: #e0882f;">=</span> <span style="color: #6d9cbe;">$item</span><span style="color: #e0882f;">;</span>
            <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_key<span style="color: #e0882f;">++;</span>
        <span style="color: #ffffff;">}</span>

        <span style="color: #ff8400;">if</span> <span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span><span style="color: #ffffff;">checkTag</span><span style="color: #ffffff;">(</span><span style="color: #ffffff;">)</span><span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>
            <span style="color: #ff8400;">if</span> <span style="color: #ffffff;">(</span><a style="color: #1299da; text-decoration: none;" href="http://www.php.net/empty"><span style="color: #e2392d;">empty</span></a><span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_weather<span style="color: #ffffff;">[</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_key <span style="color: #e0882f;">-</span> <span style="color: #1299da;">1</span><span style="color: #ffffff;">]</span><span style="color: #ffffff;">[</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_tag<span style="color: #ffffff;">]</span><span style="color: #ffffff;">)</span><span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>
                <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_weather<span style="color: #ffffff;">[</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_key <span style="color: #e0882f;">-</span> <span style="color: #1299da;">1</span><span style="color: #ffffff;">]</span><span style="color: #ffffff;">[</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_tag<span style="color: #ffffff;">]</span> <span style="color: #e0882f;">=</span> <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_attributes<span style="color: #ffffff;">[</span><span style="color: #56db3a;">'DATA'</span><span style="color: #ffffff;">]</span><span style="color: #e0882f;">;</span>
            <span style="color: #ffffff;">}</span>
        <span style="color: #ffffff;">}</span>
    <span style="color: #ffffff;">}</span>

    <span style="color: #cc7833;">public</span> <span style="color: #cc7833;">function</span> tagEnd<span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$parser</span><span style="color: #e0882f;">,</span> <span style="color: #6d9cbe;">$tagName</span> <span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>

        <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_tag <span style="color: #e0882f;">=</span> <span style="color: #cc7833;">NULL</span><span style="color: #e0882f;">;</span>
        <span style="color: #6d9cbe;">$htis</span><span style="color: #e0882f;">-&gt;</span>_attributes <span style="color: #e0882f;">=</span> <span style="color: #cc7833;">NULL</span><span style="color: #e0882f;">;</span>
    <span style="color: #ffffff;">}</span>

    <span style="color: #cc7833;">public</span> <span style="color: #cc7833;">function</span> tagContent<span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$parser</span><span style="color: #e0882f;">,</span> <span style="color: #6d9cbe;">$content</span> <span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>

        <span style="color: #ff8400;">if</span> <span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span><span style="color: #ffffff;">checkTag</span><span style="color: #ffffff;">(</span><span style="color: #ffffff;">)</span><span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>
            <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_weather<span style="color: #ffffff;">[</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_key <span style="color: #e0882f;">-</span> <span style="color: #1299da;">1</span><span style="color: #ffffff;">]</span><span style="color: #ffffff;">[</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_tag<span style="color: #ffffff;">]</span> <span style="color: #e0882f;">=</span> <span style="color: #6d9cbe;">$content</span><span style="color: #e0882f;">;</span>
        <span style="color: #ffffff;">}</span>
    <span style="color: #ffffff;">}</span>

    <span style="color: #cc7833;">public</span> <span style="color: #cc7833;">function</span> __destruct<span style="color: #ffffff;">(</span><span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>
        <a style="color: #1299da; text-decoration: none;" href="http://www.php.net/xml_parser_free"><span style="color: #e2392d;">xml_parser_free</span></a><span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_parser<span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>
    <span style="color: #ffffff;">}</span>

    <span style="color: #cc7833;">public</span> <span style="color: #cc7833;">function</span> checkTag<span style="color: #ffffff;">(</span><span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>
        <span style="color: #ff8400;">return</span> <a style="color: #1299da; text-decoration: none;" href="http://www.php.net/in_array"><span style="color: #e2392d;">in_array</span></a><span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_tag<span style="color: #e0882f;">,</span> <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_parseTags<span style="color: #ffffff;">)</span> <span style="color: #e0882f;">&amp;&amp;</span> <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_key <span style="color: #e0882f;">&gt;</span> <span style="color: #1299da;">0</span><span style="color: #e0882f;">;</span>
    <span style="color: #ffffff;">}</span>

    <span style="color: #cc7833;">public</span> <span style="color: #cc7833;">function</span> getWeather<span style="color: #ffffff;">(</span><span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>
        <span style="color: #ff8400;">return</span> <span style="color: #6d9cbe;">$this</span><span style="color: #e0882f;">-&gt;</span>_weather<span style="color: #e0882f;">;</span>
    <span style="color: #ffffff;">}</span>

<span style="color: #ffffff;">}</span>

<span style="color: #6d9cbe;">$fp</span> <span style="color: #e0882f;">=</span> <a style="color: #1299da; text-decoration: none;" href="http://www.php.net/fopen"><span style="color: #e2392d;">fopen</span></a><span style="color: #ffffff;">(</span><span style="color: #56db3a;">'weather.xml'</span><span style="color: #e0882f;">,</span> <span style="color: #56db3a;">'r'</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>

<span style="color: #6d9cbe;">$saxParser</span> <span style="color: #e0882f;">=</span> <span style="color: #cc7833;">new</span> weatherSaxParser<span style="color: #ffffff;">(</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>

<span style="color: #ff8400;">while</span> <span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$data</span> <span style="color: #e0882f;">=</span> <a style="color: #1299da; text-decoration: none;" href="http://www.php.net/fread"><span style="color: #e2392d;">fread</span></a><span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$fp</span><span style="color: #e0882f;">,</span> <span style="color: #1299da;">4096</span><span style="color: #ffffff;">)</span><span style="color: #ffffff;">)</span> <span style="color: #ffffff;">{</span>
    <span style="color: #6d9cbe;">$saxParser</span><span style="color: #e0882f;">-&gt;</span><span style="color: #ffffff;">setXmlData</span><span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$data</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>
    <span style="color: #6d9cbe;">$saxParser</span><span style="color: #e0882f;">-&gt;</span><span style="color: #ffffff;">run</span><span style="color: #ffffff;">(</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>
<span style="color: #ffffff;">}</span>

<a style="color: #1299da; text-decoration: none;" href="http://www.php.net/print_r"><span style="color: #e2392d;">print_r</span></a><span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$saxParser</span><span style="color: #e0882f;">-&gt;</span><span style="color: #ffffff;">getWeather</span><span style="color: #ffffff;">(</span><span style="color: #ffffff;">)</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span>

<a style="color: #1299da; text-decoration: none;" href="http://www.php.net/unset"><span style="color: #e2392d;">unset</span></a><span style="color: #ffffff;">(</span><span style="color: #6d9cbe;">$saxParser</span><span style="color: #ffffff;">)</span><span style="color: #e0882f;">;</span></pre>
<p style="text-indent: 2em;">以上针对XML文档中&#8217;low&#8217;, &#8216;day_of_week&#8217;, &#8216;high&#8217;, &#8216;condition&#8217;, &#8216;forecast_conditions&#8217;等标签进行处理。 在SAX解析器中，对于文档的遍历也是依赖于文件的行读取操作。</p>
<p style="text-indent: 2em;">从上面的例子我们也可以看出SAX解析器的一些缺点：</p>
<ul>
<li>SAX解释器不允许对XML文件随机存取，只能顺序读取</li>
<li>SAX解释器中元素之间的遍历困难，在多个标签间移动比较困难</li>
<li>SAX是解析一个节点后回调一个方法，把该节点相关信息传送个调用者，然后丢弃这些信息，继续解析下一个节点。它不会预存储整个XML文档，也不会在解析后保存任何解析结果。</li>
<li>SAX的修改XML能力差</li>
</ul>
<h2 style="font-weight: bold; font-family: 'Microsoft YaHei', Helvetica, Arial, sans-serif; font-size: 1.2em; color: #333333;">结论</h2>
<p style="text-indent: 2em;">DOM 采用建立树形结构的方式访问 XML 文档，它体现了预处理的编程优化思想。这对于一次获取多次查询或修改的情况较适用，并且DOM具有良好的接口定义，编程较方便，一般来说，选择DOM会舒服很多。 但是SAX也有其存在的理由，SAX 采用的事件模型，它体现了只取所需的优化思想。这对于只处理一次或数据量巨大导致无法预加载时有更好的性能。</p>
<p style="text-indent: 2em;">DOM与SAX有点类似于PHP中读取文件操作file_get_contents和fopen/fread/feof的组合。 file_get_contents的使用比较方便，并且可以一次性将所有数据取出来，仅以后调用。 fopen/fread/feof组合操作则是打开文件可以一段一段的处理。而在SAX中可能也会调用fopen/fread/feof组合。</p>
<p style="text-indent: 2em;"><strong>正所谓有得有失，重点在一个平衡和取舍，根据实际情况使用合适的技术。</strong></p>
<p style="text-indent: 2em;"><strong><br />
</strong></p>
<h2 style="font-weight: bold; font-family: 'Microsoft YaHei', Helvetica, Arial, sans-serif; font-size: 1.2em; color: #333333;">参考资料</h2>
<p style="text-indent: 2em;">http://www.ibm.com/developerworks/cn/opensource/os-xmldomphp/      http://hannoi2009.blog.163.com/blog/static/12282842820097157152651/</p>
]]></content:encoded>
			<wfw:commentRss>https://www.phppan.com/2011/03/xml-parse-dom-sax/feed/</wfw:commentRss>
		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>PHP中的XML解析的5种方法</title>
		<link>https://www.phppan.com/2009/10/phps-five-methods-of-xml-parseing/</link>
		<comments>https://www.phppan.com/2009/10/phps-five-methods-of-xml-parseing/#comments</comments>
		<pubDate>Sun, 11 Oct 2009 08:37:59 +0000</pubDate>
		<dc:creator><![CDATA[admin]]></dc:creator>
				<category><![CDATA[PHP]]></category>
		<category><![CDATA[DOM]]></category>
		<category><![CDATA[DOMDocument]]></category>
		<category><![CDATA[DOMXPath]]></category>
		<category><![CDATA[PHP应用]]></category>
		<category><![CDATA[Simplexml]]></category>
		<category><![CDATA[xml]]></category>
		<category><![CDATA[XMLReader]]></category>
		<category><![CDATA[xml_parse_into_struct]]></category>
		<category><![CDATA[xml解析]]></category>

		<guid isPermaLink="false">http://www.phppan.com/?p=306</guid>
		<description><![CDATA[【前言】 不管是桌面软件开发，还是WEB应用，XML无处不在！ 然而在平时的工作中，仅仅是使用一些已经封装好的 [&#8230;]]]></description>
				<content:encoded><![CDATA[<p>【前言】<br />
不管是桌面软件开发，还是WEB应用，XML无处不在！<br />
然而在平时的工作中，仅仅是使用一些已经封装好的类对XML对于处理，包括生成，解析等。假期有空，于是将PHP中的几种XML解析方法总结如下：</p>
<p>以解析Google API 接口提供的天气情况为例，我们取今天的天气及气温。<br />
API地址：http://www.google.com/ig/api?weather=shenzhen</p>
<p>【XML文件内容】</p>

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</pre></td><td class="code"><pre class="xml" style="font-family:monospace;"><span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;?xml</span> <span style="color: #000066;">version</span>=<span style="color: #ff0000;">&quot;1.0&quot;</span><span style="color: #000000; font-weight: bold;">?&gt;</span></span>
<span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;xml_api_reply</span> <span style="color: #000066;">version</span>=<span style="color: #ff0000;">&quot;1&quot;</span><span style="color: #000000; font-weight: bold;">&gt;</span></span>
    <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;weather</span> <span style="color: #000066;">module_id</span>=<span style="color: #ff0000;">&quot;0&quot;</span> <span style="color: #000066;">tab_id</span>=<span style="color: #ff0000;">&quot;0&quot;</span> <span style="color: #000066;">mobile_row</span>=<span style="color: #ff0000;">&quot;0&quot;</span> <span style="color: #000066;">mobile_zipped</span>=<span style="color: #ff0000;">&quot;1&quot;</span> <span style="color: #000066;">row</span>=<span style="color: #ff0000;">&quot;0&quot;</span> <span style="color: #000066;">section</span>=<span style="color: #ff0000;">&quot;0&quot;</span> <span style="color: #000000; font-weight: bold;">&gt;</span></span>
        <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;forecast_information<span style="color: #000000; font-weight: bold;">&gt;</span></span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;city</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;Shenzhen, Guangdong&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;postal_code</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;shenzhen&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;latitude_e6</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;longitude_e6</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;forecast_date</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;2009-10-05&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;current_date_time</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;2009-10-04 05:02:00 +0000&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;unit_system</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;US&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
        <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;/forecast_information<span style="color: #000000; font-weight: bold;">&gt;</span></span></span>
        <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;current_conditions<span style="color: #000000; font-weight: bold;">&gt;</span></span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;condition</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;Sunny&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;temp_f</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;88&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;temp_c</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;31&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;humidity</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;Humidity: 49%&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;icon</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;/ig/images/weather/sunny.gif&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
            <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;wind_condition</span> <span style="color: #000066;">data</span>=<span style="color: #ff0000;">&quot;Wind:  mph&quot;</span><span style="color: #000000; font-weight: bold;">/&gt;</span></span>
        <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;/current_conditions<span style="color: #000000; font-weight: bold;">&gt;</span></span></span>
    <span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;/weather<span style="color: #000000; font-weight: bold;">&gt;</span></span></span>
<span style="color: #009900;"><span style="color: #000000; font-weight: bold;">&lt;/xml_api_reply<span style="color: #000000; font-weight: bold;">&gt;</span></span></span></pre></td></tr></table></div>

<p>【使用DomDocument解析】</p>

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</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #000000; font-weight: bold;">&lt;?PHP</span>
<span style="color: #990000;">header</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;Content-type:text/html; Charset=utf-8&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$url</span> <span style="color: #339933;">=</span> <span style="color: #0000ff;">&quot;http://www.google.com/ig/api?weather=shenzhen&quot;</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #666666; font-style: italic;">//  加载XML内容</span>
<span style="color: #000088;">$content</span> <span style="color: #339933;">=</span> <span style="color: #990000;">file_get_contents</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$url</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$content</span> <span style="color: #339933;">=</span> get_utf8_string<span style="color: #009900;">&#40;</span><span style="color: #000088;">$content</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$dom</span> <span style="color: #339933;">=</span> DOMDocument<span style="color: #339933;">::</span><span style="color: #004000;">loadXML</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$content</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #666666; font-style: italic;">/*
此处也可使用如下所示的代码，
$dom = new DOMDocument();
$dom-&gt;load($url);
 */</span>
&nbsp;
<span style="color: #000088;">$elements</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$dom</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">getElementsByTagName</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;current_conditions&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$element</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$elements</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">item</span><span style="color: #009900;">&#40;</span><span style="color: #cc66cc;">0</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$condition</span> <span style="color: #339933;">=</span> get_google_xml_data<span style="color: #009900;">&#40;</span><span style="color: #000088;">$element</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">&quot;condition&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$temp_c</span> <span style="color: #339933;">=</span> get_google_xml_data<span style="color: #009900;">&#40;</span><span style="color: #000088;">$element</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">&quot;temp_c&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">echo</span> <span style="color: #0000ff;">'天气：'</span><span style="color: #339933;">,</span> <span style="color: #000088;">$condition</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'&lt;br /&gt;'</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">echo</span> <span style="color: #0000ff;">'温度：'</span><span style="color: #339933;">,</span> <span style="color: #000088;">$temp_c</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'&lt;br /&gt;'</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #000000; font-weight: bold;">function</span> get_utf8_string<span style="color: #009900;">&#40;</span><span style="color: #000088;">$content</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>    <span style="color: #666666; font-style: italic;">//  将一些字符转化成utf8格式</span>
    <span style="color: #000088;">$encoding</span> <span style="color: #339933;">=</span> <span style="color: #990000;">mb_detect_encoding</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$content</span><span style="color: #339933;">,</span> <span style="color: #990000;">array</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'ASCII'</span><span style="color: #339933;">,</span><span style="color: #0000ff;">'UTF-8'</span><span style="color: #339933;">,</span><span style="color: #0000ff;">'GB2312'</span><span style="color: #339933;">,</span><span style="color: #0000ff;">'GBK'</span><span style="color: #339933;">,</span><span style="color: #0000ff;">'BIG5'</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
    <span style="color: #b1b100;">return</span>  <span style="color: #990000;">mb_convert_encoding</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$content</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'utf-8'</span><span style="color: #339933;">,</span> <span style="color: #000088;">$encoding</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span>
&nbsp;
<span style="color: #000000; font-weight: bold;">function</span> get_google_xml_data<span style="color: #009900;">&#40;</span><span style="color: #000088;">$element</span><span style="color: #339933;">,</span> <span style="color: #000088;">$tagname</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
    <span style="color: #000088;">$tags</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$element</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">getElementsByTagName</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$tagname</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>   <span style="color: #666666; font-style: italic;">//  取得所有的$tagname</span>
&nbsp;
    <span style="color: #000088;">$tag</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$tags</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">item</span><span style="color: #009900;">&#40;</span><span style="color: #cc66cc;">0</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>  <span style="color: #666666; font-style: italic;">//  获取第一个以$tagname命名的标签</span>
    <span style="color: #b1b100;">if</span> <span style="color: #009900;">&#40;</span><span style="color: #000088;">$tag</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">hasAttributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>    <span style="color: #666666; font-style: italic;">//  获取data属性</span>
        <span style="color: #000088;">$attribute</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$tag</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">getAttribute</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;data&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
        <span style="color: #b1b100;">return</span> <span style="color: #000088;">$attribute</span><span style="color: #339933;">;</span>
    <span style="color: #009900;">&#125;</span><span style="color: #b1b100;">else</span> <span style="color: #009900;">&#123;</span>
        <span style="color: #b1b100;">return</span> <span style="color: #009900; font-weight: bold;">false</span><span style="color: #339933;">;</span>
    <span style="color: #009900;">&#125;</span>
<span style="color: #009900;">&#125;</span>
<span style="color: #000000; font-weight: bold;">?&gt;</span></pre></td></tr></table></div>

<p>这只是一个简单的示例，仅包括了loadXML, item, getAttribute,getElementsByTagName等方法，还有一些有用的方法，这个依据你的实际需要。</p>
<p>【XMLReader】<br />
 当我们要用php解读xml的内容时，有很多物件提供函式，让我们不用一个一个字元去解析，而只要根据标签和属性名称，就能取出文件中的属性与内容了，相较之下方便许多。其中XMLReader循序地浏览过xml档案的节点，可以想像成游标走过整份文件的节点，并抓取需要的内容。</p>

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</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #000000; font-weight: bold;">&lt;?PHP</span>
<span style="color: #990000;">header</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;Content-type:text/html; Charset=utf-8&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$url</span> <span style="color: #339933;">=</span> <span style="color: #0000ff;">&quot;http://www.google.com/ig/api?weather=shenzhen&quot;</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #666666; font-style: italic;">//  加载XML内容</span>
<span style="color: #000088;">$xml</span> <span style="color: #339933;">=</span> <span style="color: #000000; font-weight: bold;">new</span> XMLReader<span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">open</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$url</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #000088;">$condition</span> <span style="color: #339933;">=</span> <span style="color: #0000ff;">''</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$temp_c</span> <span style="color: #339933;">=</span> <span style="color: #0000ff;">''</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">while</span> <span style="color: #009900;">&#40;</span><span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">read</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
<span style="color: #666666; font-style: italic;">//      echo $xml-&gt;name, &quot;==&gt;&quot;, $xml-&gt;depth, &quot;&lt;br&gt;&quot;;</span>
      <span style="color: #b1b100;">if</span> <span style="color: #009900;">&#40;</span><span style="color: #339933;">!</span><span style="color: #990000;">empty</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$condition</span><span style="color: #009900;">&#41;</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #339933;">!</span><span style="color: #990000;">empty</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$temp_c</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
          <span style="color: #b1b100;">break</span><span style="color: #339933;">;</span>
      <span style="color: #009900;">&#125;</span>
      <span style="color: #b1b100;">if</span> <span style="color: #009900;">&#40;</span><span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">name</span> <span style="color: #339933;">==</span> <span style="color: #0000ff;">'condition'</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #990000;">empty</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$condition</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>  <span style="color: #666666; font-style: italic;">//  取第一个condition</span>
            <span style="color: #000088;">$condition</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">getAttribute</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'data'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
      <span style="color: #009900;">&#125;</span>
&nbsp;
      <span style="color: #b1b100;">if</span> <span style="color: #009900;">&#40;</span><span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">name</span> <span style="color: #339933;">==</span> <span style="color: #0000ff;">'temp_c'</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #990000;">empty</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$temp_c</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>    <span style="color: #666666; font-style: italic;">//  取第一个temp_c</span>
          <span style="color: #000088;">$temp_c</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">getAttribute</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'data'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
      <span style="color: #009900;">&#125;</span>
&nbsp;
      <span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">read</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span>
&nbsp;
<span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">close</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">echo</span> <span style="color: #0000ff;">'天气：'</span><span style="color: #339933;">,</span> <span style="color: #000088;">$condition</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'&lt;br /&gt;'</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">echo</span> <span style="color: #0000ff;">'温度：'</span><span style="color: #339933;">,</span> <span style="color: #000088;">$temp_c</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'&lt;br /&gt;'</span><span style="color: #339933;">;</span></pre></td></tr></table></div>

<p>我们只是需要取第一个condition和第一个temp_c,于是遍历所有的节点，将遇到的第一个condition和第一个temp_c写入变量，最后输出。</p>
<p>【DOMXPath】<br />
这种方法需要使用DOMDocument对象创建整个文档的结构，</p>

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</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #000000; font-weight: bold;">&lt;?PHP</span>
<span style="color: #990000;">header</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;Content-type:text/html; Charset=utf-8&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$url</span> <span style="color: #339933;">=</span> <span style="color: #0000ff;">&quot;http://www.google.com/ig/api?weather=shenzhen&quot;</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #666666; font-style: italic;">//  加载XML内容</span>
<span style="color: #000088;">$dom</span> <span style="color: #339933;">=</span> <span style="color: #000000; font-weight: bold;">new</span> DOMDocument<span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$dom</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">load</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$url</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #000088;">$xpath</span> <span style="color: #339933;">=</span> <span style="color: #000000; font-weight: bold;">new</span> DOMXPath<span style="color: #009900;">&#40;</span><span style="color: #000088;">$dom</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$element</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$xpath</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">query</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;/xml_api_reply/weather/current_conditions&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">item</span><span style="color: #009900;">&#40;</span><span style="color: #cc66cc;">0</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$condition</span> <span style="color: #339933;">=</span> get_google_xml_data<span style="color: #009900;">&#40;</span><span style="color: #000088;">$element</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">&quot;condition&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$temp_c</span> <span style="color: #339933;">=</span> get_google_xml_data<span style="color: #009900;">&#40;</span><span style="color: #000088;">$element</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">&quot;temp_c&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">echo</span> <span style="color: #0000ff;">'天气：'</span><span style="color: #339933;">,</span> <span style="color: #000088;">$condition</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'&lt;br /&gt;'</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">echo</span> <span style="color: #0000ff;">'温度：'</span><span style="color: #339933;">,</span> <span style="color: #000088;">$temp_c</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'&lt;br /&gt;'</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #000000; font-weight: bold;">function</span> get_google_xml_data<span style="color: #009900;">&#40;</span><span style="color: #000088;">$element</span><span style="color: #339933;">,</span> <span style="color: #000088;">$tagname</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
    <span style="color: #000088;">$tags</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$element</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">getElementsByTagName</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$tagname</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>   <span style="color: #666666; font-style: italic;">//  取得所有的$tagname</span>
&nbsp;
    <span style="color: #000088;">$tag</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$tags</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">item</span><span style="color: #009900;">&#40;</span><span style="color: #cc66cc;">0</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>  <span style="color: #666666; font-style: italic;">//  获取第一个以$tagname命名的标签</span>
    <span style="color: #b1b100;">if</span> <span style="color: #009900;">&#40;</span><span style="color: #000088;">$tag</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">hasAttributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>    <span style="color: #666666; font-style: italic;">//  获取data属性</span>
        <span style="color: #000088;">$attribute</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$tag</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">getAttribute</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;data&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
        <span style="color: #b1b100;">return</span> <span style="color: #000088;">$attribute</span><span style="color: #339933;">;</span>
    <span style="color: #009900;">&#125;</span><span style="color: #b1b100;">else</span> <span style="color: #009900;">&#123;</span>
        <span style="color: #b1b100;">return</span> <span style="color: #009900; font-weight: bold;">false</span><span style="color: #339933;">;</span>
    <span style="color: #009900;">&#125;</span>
<span style="color: #009900;">&#125;</span>
<span style="color: #000000; font-weight: bold;">?&gt;</span></pre></td></tr></table></div>

<p>【xml_parse_into_struct】<br />
说明：int xml_parse_into_struct ( resource parser, string data, array &#038;values [, array &#038;index] )</p>
<p>该函数将 XML 文件解析到两个对应的数组中，index 参数含有指向 values 数组中对应值的指针。最后两个数组参数可由指针传递给函数。<br />
注意:  xml_parse_into_struct() 失败返回 0，成功返回 1。这和 FALSE 与 TRUE 不同，使用例如 === 的运算符时要注意。</p>

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</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #000000; font-weight: bold;">&lt;?PHP</span>
<span style="color: #990000;">header</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;Content-type:text/html; Charset=utf-8&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$url</span> <span style="color: #339933;">=</span> <span style="color: #0000ff;">&quot;http://www.google.com/ig/api?weather=shenzhen&quot;</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #666666; font-style: italic;">//  加载XML内容</span>
<span style="color: #000088;">$content</span> <span style="color: #339933;">=</span> <span style="color: #990000;">file_get_contents</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$url</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$p</span> <span style="color: #339933;">=</span> <span style="color: #990000;">xml_parser_create</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #990000;">xml_parse_into_struct</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$p</span><span style="color: #339933;">,</span> <span style="color: #000088;">$content</span><span style="color: #339933;">,</span> <span style="color: #000088;">$vals</span><span style="color: #339933;">,</span> <span style="color: #000088;">$index</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #990000;">xml_parser_free</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$p</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #b1b100;">echo</span> <span style="color: #0000ff;">'天气：'</span><span style="color: #339933;">,</span> <span style="color: #000088;">$vals</span><span style="color: #009900;">&#91;</span><span style="color: #000088;">$index</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'CONDITION'</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#91;</span><span style="color: #cc66cc;">0</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'attributes'</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'DATA'</span><span style="color: #009900;">&#93;</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'&lt;br /&gt;'</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">echo</span> <span style="color: #0000ff;">'温度：'</span><span style="color: #339933;">,</span> <span style="color: #000088;">$vals</span><span style="color: #009900;">&#91;</span><span style="color: #000088;">$index</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'TEMP_C'</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#91;</span><span style="color: #cc66cc;">0</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'attributes'</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'DATA'</span><span style="color: #009900;">&#93;</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'&lt;br /&gt;'</span><span style="color: #339933;">;</span></pre></td></tr></table></div>

<p>【Simplexml】<br />
此方法在PHP5中可用<br />
这个在google的官方文档中有相关的例子，如下：</p>

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</pre></td><td class="code"><pre class="php" style="font-family:monospace;"><span style="color: #666666; font-style: italic;">// Charset: utf-8</span>
<span style="color: #009933; font-style: italic;">/**
  * 用php Simplexml 调用google天气预报api,和g官方的例子不一样
  * google 官方php domxml 获取google天气预报的例子
  * http://www.google.com/tools/toolbar/buttons/intl/zh-CN/apis/howto_guide.html
  *
  * @copyright Copyright (c) 2008 &lt;cmpan(at)qq.com&gt;
  * @license New BSD License
  * @version 2008-11-9
  */</span>
&nbsp;
<span style="color: #666666; font-style: italic;">// 城市，用城市拼音</span>
<span style="color: #000088;">$city</span> <span style="color: #339933;">=</span> <span style="color: #990000;">empty</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$_GET</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'city'</span><span style="color: #009900;">&#93;</span><span style="color: #009900;">&#41;</span> ? <span style="color: #0000ff;">'shenzhen'</span> <span style="color: #339933;">:</span> <span style="color: #000088;">$_GET</span><span style="color: #009900;">&#91;</span><span style="color: #0000ff;">'city'</span><span style="color: #009900;">&#93;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$content</span> <span style="color: #339933;">=</span> <span style="color: #990000;">file_get_contents</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;http://www.google.com/ig/api?weather=<span style="color: #006699; font-weight: bold;">$city</span>&amp;hl=zh-cn&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$content</span> <span style="color: #339933;">||</span> <span style="color: #990000;">die</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">&quot;No such city's data&quot;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$content</span> <span style="color: #339933;">=</span> <span style="color: #990000;">mb_convert_encoding</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$content</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'UTF-8'</span><span style="color: #339933;">,</span> <span style="color: #0000ff;">'GBK'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$xml</span> <span style="color: #339933;">=</span> <span style="color: #990000;">simplexml_load_string</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$content</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #000088;">$date</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">weather</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">forecast_information</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">forecast_date</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$html</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$date</span><span style="color: #339933;">.</span> <span style="color: #0000ff;">&quot;&lt;br&gt;<span style="color: #000099; font-weight: bold;">\r</span><span style="color: #000099; font-weight: bold;">\n</span>&quot;</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #000088;">$current</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">weather</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">current_conditions</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #000088;">$condition</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$current</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">condition</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$temp_c</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$current</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">temp_c</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$humidity</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$current</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">humidity</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$icon</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$current</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">icon</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$wind</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$current</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">wind_condition</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #000088;">$condition</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #000088;">$condition</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">weather</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">forecast_conditions</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">condition</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #000088;">$icon</span> <span style="color: #339933;">&amp;&amp;</span> <span style="color: #000088;">$icon</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">weather</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">forecast_conditions</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">icon</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #000088;">$html</span><span style="color: #339933;">.=</span> <span style="color: #0000ff;">&quot;当前: <span style="color: #006699; font-weight: bold;">{$condition}</span>, <span style="color: #006699; font-weight: bold;">{$temp_c}</span>°C,&lt;img src='http://www.google.com/ig<span style="color: #006699; font-weight: bold;">{$icon}</span>'/&gt; <span style="color: #006699; font-weight: bold;">{$humidity}</span> <span style="color: #006699; font-weight: bold;">{$wind}</span> &lt;br /&gt;<span style="color: #000099; font-weight: bold;">\r</span><span style="color: #000099; font-weight: bold;">\n</span>&quot;</span><span style="color: #339933;">;</span>
&nbsp;
<span style="color: #b1b100;">foreach</span><span style="color: #009900;">&#40;</span><span style="color: #000088;">$xml</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">weather</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">forecast_conditions</span> <span style="color: #b1b100;">as</span> <span style="color: #000088;">$forecast</span><span style="color: #009900;">&#41;</span> <span style="color: #009900;">&#123;</span>
    <span style="color: #000088;">$low</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$forecast</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">low</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
    <span style="color: #000088;">$high</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$forecast</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">high</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
    <span style="color: #000088;">$icon</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$forecast</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">icon</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
    <span style="color: #000088;">$condition</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$forecast</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">condition</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
    <span style="color: #000088;">$day_of_week</span> <span style="color: #339933;">=</span> <span style="color: #000088;">$forecast</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">day_of_week</span><span style="color: #339933;">-&gt;</span><span style="color: #004000;">attributes</span><span style="color: #009900;">&#40;</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
    <span style="color: #000088;">$html</span><span style="color: #339933;">.=</span> <span style="color: #0000ff;">&quot;<span style="color: #006699; font-weight: bold;">{$day_of_week}</span> : <span style="color: #006699; font-weight: bold;">{$high}</span> / <span style="color: #006699; font-weight: bold;">{$low}</span> °C, <span style="color: #006699; font-weight: bold;">{$condition}</span> &lt;img src='http://www.google.com/ig<span style="color: #006699; font-weight: bold;">{$icon}</span>' /&gt;&lt;br /&gt;<span style="color: #000099; font-weight: bold;">\r</span><span style="color: #000099; font-weight: bold;">\n</span>&quot;</span><span style="color: #339933;">;</span>
<span style="color: #009900;">&#125;</span>
&nbsp;
<span style="color: #990000;">header</span><span style="color: #009900;">&#40;</span><span style="color: #0000ff;">'Content-type: text/html; Charset: utf-8'</span><span style="color: #009900;">&#41;</span><span style="color: #339933;">;</span>
<span style="color: #b1b100;">print</span> <span style="color: #000088;">$html</span><span style="color: #339933;">;</span>
<span style="color: #000000; font-weight: bold;">?&gt;</span></pre></td></tr></table></div>

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