XPath的运算符需要转义吗？

<blockquote>XPath运算符无需转义，直接使用+、-、*、=、and、or等；但在XML属性中需对、&等字符进行XML实体转义，如、&；字符串引号冲突时用单双引号互避，或concat()函数拼接。</blockquote><p><img src="https://img.php.cn/upload/article/001/221/864/175544532686015.jpg" alt="xpath的<和>运算符需要转义吗？"></p><p>XPath的运算符本身，在XPath表达式内部使用时，通常不需要“转义”。它们是语言的组成部分，直接书写即可，比如<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">+</pre>

</div>、<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">-</pre>

</div>、<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">*</pre>

</div>、<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">=</pre>

</div>、<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">and</pre>

</div>、<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">or</pre>

</div>等等。但如果你的XPath表达式字符串本身被嵌入到其他语言环境（例如XML属性值、编程语言的<a style="color:#f60; text-decoration:underline;" title="字符串常量" href="https://www.php.cn/zt/81514.html" target="_blank">字符串常量</a>）中，那么这些外部语言的规则可能会要求你对XPath字符串中的特定字符进行转义，这与XPath运算符本身无关，而是外部语言的语法要求。真正的挑战往往出现在字符串字面量中的引号处理，以及当XPath表达式作为XML属性值时对XML特殊字符的转义。</p><h3>解决方案</h3><p>我们在写XPath的时候，直观上会觉得某些符号是不是得特别处理一下，尤其当你从其他编程语言的背景看过来。但对于XPath的核心运算符，比如加减乘除、逻辑判断（<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">and</pre>

</div>, <div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">or</pre>

</div>, <div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">not</pre>

</div>）、比较运算符（<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">=</pre>

</div>, <div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">!=</pre>

</div>, <div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;"><</pre>

</div>, <div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">></pre>

</div>, <div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;"><=</pre>

</div>, <div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">>=</pre>

</div>），它们就是直接用的。你写<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">price > 10</pre>

</div>，那个<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">></pre>

</div>就是<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">></pre>

</div>，不需要写成<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">\></pre>

</div>或者别的什么。</p><p>真正的“陷阱”或者说需要“变通”的地方，主要集中在两个方面：</p><ol><li><p><strong>XPath字符串字面量中的引号处理</strong>：这是最常见的问题。如果你想在XPath中匹配一个包含引号的字符串，比如<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">"It’s a test"</pre>

</div>，你就不能简单地用单引号包围它，因为字符串内部的单引号会提前结束你的字符串。XPath本身没有像大多数编程语言那样的反斜杠转义机制（例如<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">\’</pre>

</div>或<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">\"</pre>

</div>）。它的解决方式是：</p><ul><li>如果你的字符串内容包含单引号（<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">’</pre>

</div>），就用双引号（<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">"</pre>

</div>）来包围整个字符串。例如：<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">//item[text()="It’s a great day"]</pre>

</div>。</li><li>如果你的字符串内容包含双引号（<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">"</pre>

</div>），就用单引号（<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">’</pre>

</div>）来包围整个字符串。例如：<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">//item[text()=’He said "Hello!"’]</pre>

</div>。</li><li>如果你的字符串内容既包含单引号又包含双引号，或者你需要匹配的字符串正好是当前字符串定界符的类型，那就需要使用<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">concat()</pre>

</div>函数来拼接字符串。这是XPath 1.0时代最常用的策略，虽然有点啰嗦，但非常可靠。例如，要匹配字符串<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">It’s "really" good</pre>

</div>，你可以这样写：<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">concat(‘It’, "’", ‘s "really" good’)</pre>

</div>。</li></ul></li><li><p><strong>XPath表达式作为XML/HTML属性值时的XML实体转义</strong>：当你把一个XPath表达式放在XML或HTML标签的属性里时，比如在一个XSLT样式表的<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">select</pre>

</div>属性中，XML解析器会先处理这个属性值。XML有它自己的特殊字符，例如<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;"><</pre>

</div>、<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">></pre>

</div>、<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">&</pre>

</div>、<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">"</pre>

</div>、<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false;">’</pre>

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;。如果你的XPath表达式中包含了这些字符，它们必须按照XML的规则进行实体转义，否则XML解析会报错。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;ul&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;li&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;<&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; 代替 &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; (小于号)&amp;amp;amp;amp;amp;lt;/li&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;li&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;>&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; 代替 &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; (大于号)&amp;amp;amp;amp;amp;lt;/li&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;li&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; 代替 &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; (和号)&amp;amp;amp;amp;amp;lt;/li&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;li&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; 代替 &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; (双引号，当属性值用双引号包围时，如果内容也需要双引号)&amp;amp;amp;amp;amp;lt;/li&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;li&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;apos;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; 代替 &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;’&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; (单引号，当属性值用单引号包围时，如果内容也需要单引号)最常见的是比较运算符&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;和&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;。比如，&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;select=&amp;amp;amp;amp;amp;quot;a[@id &amp;amp;amp;amp;amp;lt; 10]&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;在XML属性中就是错误的，必须写成&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;select=&amp;amp;amp;amp;amp;quot;a[@id < 10]&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;。&amp;amp;amp;amp;amp;lt;/li&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;/ul&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;/li&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;/ol&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;理解这两点，基本就能解决XPath中所有关于“转义”的困惑了。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;h3&amp;amp;amp;amp;amp;gt;XPath字符串中引号的处理方法&amp;amp;amp;amp;amp;lt;/h3&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;处理XPath字符串中的引号，其实就是个“避让”的策略，而不是传统意义上的字符转义。我个人觉得，这地方是很多初学者最容易卡壳的地方，因为大家习惯了编程语言里用反斜杠&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;\&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;来转义的模式。但XPath它就是这么设计的，简单粗暴但有效。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;aritcle_card&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;a class=&amp;amp;amp;amp;amp;quot;aritcle_card_img&amp;amp;amp;amp;amp;quot; href=&amp;amp;amp;amp;amp;quot;/ai/839&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;img src=&amp;amp;amp;amp;amp;quot;https://img.php.cn/upload/ai_manual/000/000/000/175680126275698.png&amp;amp;amp;amp;amp;quot; alt=&amp;amp;amp;amp;amp;quot;QoQo&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;/a&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;aritcle_card_info&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;a href=&amp;amp;amp;amp;amp;quot;/ai/839&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;QoQo&amp;amp;amp;amp;amp;lt;/a&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;QoQo是一款专注于UX设计的AI工具，可以帮助UX设计师生成用户角色卡片、用户旅程图、用户访谈问卷等。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;img src=&amp;amp;amp;amp;amp;quot;/static/images/card_xiazai.png&amp;amp;amp;amp;amp;quot; alt=&amp;amp;amp;amp;amp;quot;QoQo&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;span&amp;amp;amp;amp;amp;gt;172&amp;amp;amp;amp;amp;lt;/span&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;a href=&amp;amp;amp;amp;amp;quot;/ai/839&amp;amp;amp;amp;amp;quot; class=&amp;amp;amp;amp;amp;quot;aritcle_card_btn&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;span&amp;amp;amp;amp;amp;gt;查看详情&amp;amp;amp;amp;amp;lt;/span&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;img src=&amp;amp;amp;amp;amp;quot;/static/images/cardxiayige-3.png&amp;amp;amp;amp;amp;quot; alt=&amp;amp;amp;amp;amp;quot;QoQo&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;/a&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; &amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;当你需要匹配的文本内容本身包含引号时，你得灵活选择用来包围整个字符串的引号类型。比如，你有一个XML节点，其文本内容是&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;It’s a beautiful day!&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;。如果你想匹配它，你不能写&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;//someNode[text()=’It’s a beautiful day!’]&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;。因为第一个单引号后面的&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;s&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;会让XPath认为字符串已经结束了，然后&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;s&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;就成了语法错误。这时候，你得用双引号来包围整个字符串：&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;//someNode[text()=&amp;amp;amp;amp;amp;quot;It’s a beautiful day!&amp;amp;amp;amp;amp;quot;]&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;反过来也一样。如果文本内容是&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;He said &amp;amp;amp;amp;amp;quot;Hello!&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;，你就得用单引号：&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;//anotherNode[text()=’He said &amp;amp;amp;amp;amp;quot;Hello!&amp;amp;amp;amp;amp;quot;’]&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;那如果文本内容是&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;It’s &amp;amp;amp;amp;amp;quot;really&amp;amp;amp;amp;amp;quot; good!&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;呢？既有单引号又有双引号，这时候就没法简单地用一种引号来包围了。这正是&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;concat()&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;函数大显身手的时候。&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;concat()&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;函数可以接受任意数量的参数，并将它们连接成一个字符串。所以，你可以把字符串拆分成几部分，然后用&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;concat()&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;拼接起来。例如：&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;//item[text()=concat(‘It’, &amp;amp;amp;amp;amp;quot;’&amp;amp;amp;amp;amp;quot;, ‘s &amp;amp;amp;amp;amp;quot;really&amp;amp;amp;amp;amp;quot; good!’)]&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;。这里，&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;’&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;是一个包含单引号的字符串，&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;’s &amp;amp;amp;amp;amp;quot;really&amp;amp;amp;amp;amp;quot; good!’&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;是另一个。这样，XPath就能正确解析你的意图了。这种方法虽然看起来有点笨拙，但它在XPath 1.0中是处理复杂字符串字面量的标准且唯一的方式。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;h3&amp;amp;amp;amp;amp;gt;XPath表达式在XML属性中如何书写？&amp;amp;amp;amp;amp;lt;/h3&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;当我们将XPath表达式嵌入到XML或HTML文档的属性值中时，比如在XSLT的&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;xsl:value-of select=&amp;amp;amp;amp;amp;quot;…&amp;amp;amp;amp;amp;quot;/&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;或者&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;web.xml&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;配置文件的某个XPath表达式，就必须遵守XML的属性值规则。这意味着，任何在XPath表达式中出现的XML保留字符（&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;, &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;, &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;, &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;, &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;’&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;）都必须被替换为它们对应的XML实体。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;这是一个非常常见的错误点，因为XPath本身可能没问题，但XML解析器会先对整个文档进行解析。比如，你想选择所有&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;id&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;小于10的元素：&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;//element[@id &amp;amp;amp;amp;amp;lt; 10]&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;。如果你直接把这个放到XML属性里，比如&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;select=&amp;amp;amp;amp;amp;quot;//element[@id &amp;amp;amp;amp;amp;lt; 10]&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;，XML解析器一看到&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;就会认为这是标签的开始，然后报错。所以，你必须将其转义为&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;<&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;：&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;select=&amp;amp;amp;amp;amp;quot;//element[@id < 10]&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;同理，大于号&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;需要写成&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;>&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;。逻辑与&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;and&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;操作符的&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;符号也需要转义成&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;，尽管XPath中更常用的是直接写&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;and&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;这个关键字，而不是&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;符号。例如，一个更复杂的例子：&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;select=&amp;amp;amp;amp;amp;quot;items/item[price > 100 and @category=’electronics’]&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;这里，&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;被转义了，而&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;@category=’electronics’&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;中的单引号因为属性值是双引号包围的，所以不需要额外转义。但如果你的XPath字符串内部需要双引号，并且你的XML属性也是用双引号包围的，那么内部的双引号就得用&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;来表示。例如：&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;select=’items/item[@description=&amp;amp;amp;amp;amp;quot;He said &amp;amp;amp;amp;amp;quot;Hello&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;quot;]’&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;（注意这里XML属性本身用单引号包围，所以XPath字符串内部的双引号需要转义）。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;总而言之，记住一点：当XPath表达式成为XML属性值的一部分时，它首先是一个XML属性值，然后才是一个XPath表达式。所以，XML的语法规则优先级更高。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;h3&amp;amp;amp;amp;amp;gt;XPath运算符的优先级与括号使用&amp;amp;amp;amp;amp;lt;/h3&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;XPath中的运算符，就像大多数编程语言一样，有它们固定的优先级规则。理解这些优先级对于编写复杂且行为正确的XPath表达式至关重要，否则你可能会得到意想不到的结果。这不是“转义”的问题，而是确保表达式按照你的意图被计算的问题。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;比如，数学运算符的优先级通常是乘除高于加减。在XPath中也是如此。&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;1 + 2 * 3&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; 结果是 &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;7&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; (先算 &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;2 * 3 = 6&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;，再加 &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;1&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;)如果你想要先执行加法，再执行乘法，就必须使用括号&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;()&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;来明确指定运算顺序。&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;(1 + 2) * 3&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; 结果是 &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;9&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt; (先算 &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;1 + 2 = 3&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;，再乘 &amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;3&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;)&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;逻辑运算符也有优先级。&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;and&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;通常比&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;or&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;的优先级高。&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;//item[category=’book’ and price &amp;amp;amp;amp;amp;gt; 50 or stock &amp;amp;amp;amp;amp;lt; 10]&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;这个表达式的实际含义是：&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;//item[(category=’book’ and price &amp;amp;amp;amp;amp;gt; 50) or stock &amp;amp;amp;amp;amp;lt; 10]&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;它会先判断&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;category=’book’ and price &amp;amp;amp;amp;amp;gt; 50&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;这个条件，然后将结果与&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;stock &amp;amp;amp;amp;amp;lt; 10&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;进行或运算。这意味着，即使&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;category&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;不是&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;book&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;且&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;price&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;不高，只要&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;stock &amp;amp;amp;amp;amp;lt; 10&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;，这个&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;item&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;也会被选中。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;如果你希望的是：&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;//item[category=’book’ and (price &amp;amp;amp;amp;amp;gt; 50 or stock &amp;amp;amp;amp;amp;lt; 10)]&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;也就是，必须是&amp;amp;amp;amp;amp;lt;div class=&amp;amp;amp;amp;amp;quot;code&amp;amp;amp;amp;amp;quot; style=&amp;amp;amp;amp;amp;quot;position:relative; padding:0px; margin:0px;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;pre class=&amp;amp;amp;amp;amp;quot;brush:php;toolbar:false;&amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;gt;book&amp;amp;amp;amp;amp;lt;/pre&amp;amp;amp;amp;amp;gt;

&amp;amp;amp;amp;amp;lt;/div&amp;amp;amp;amp;amp;gt;类别，并且满足价格大于50 &amp;amp;amp;amp;amp;lt;em&amp;amp;amp;amp;amp;gt;或者&amp;amp;amp;amp;amp;lt;/em&amp;amp;amp;amp;amp;gt; 库存小于10这两个条件中的一个。这时候，括号就是不可或缺的，它能强制XPath按照你期望的逻辑顺序进行计算。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;lt;p&amp;amp;amp;amp;amp;gt;所以，当你的XPath表达式变得复杂，涉及到多个运算符和条件时，不要吝啬使用括号。括号不仅能确保表达式的正确性，也能大大提高表达式的可读性，让其他人（包括未来的你自己）更容易理解你的意图。这是一种良好的编程习惯，在XPath中同样适用。&amp;amp;amp;amp;amp;lt;/p&amp;amp;amp;amp;amp;gt;

以上就是XPath的运算符需要转义吗？的详细内容，更多请关注创想鸟其它相关文章！