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<td width="90%"><font size="4" face="Verdana, Arial, Helvetica"><b>使用 XDoclet 的 webdoclet 任务来创建定制标记 TLD</b></font></td><td width="200" align="right"><font size="1" face="Verdana, Arial, Helvetica"><nobr> 第 1 页（共4 页）</nobr></font></td>
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<td width="90%"><font size="4" face="Verdana, Arial, Helvetica"><b>定制标记的类级别 JavaDoc 标记</b></font></td><td width="200" align="right"><font size="1" face="Verdana, Arial, Helvetica"><nobr> 第 1 页（共4 页）</nobr></font></td>
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<p>
与前面相似，映射是很自然的。第一步是定义 jsp 标记（使用 jsp.tag 并传递定制标记的名称），如下所示：
<pre>
<code style="font-family: Courier New, Courier, monospace; font-size: 12">
* @jsp.tag name="BasicTag"
</code>
</pre>
这段代码生成 TLD 文件中的以下代码：
<pre>
<code style="font-family: Courier New, Courier, monospace; font-size: 12">
<tag>
<name>BasicTag</name>
<tag-class>tomcatbook.customtag.BasicTag</tag-class>
...
</tag>
</code>
</pre>
别忘了，XDoclet 使用 JavaDoc API 来获取定制标记处理程序的完整的类名。接着，您定义使用定制标记的 JSP 页面可用的任何变量。在这个示例中，您定义三个变量。其中一个变量被用于开始标记后，另一个仅用于结束标记后，还有一个仅用于主体中，如下所示：</p>
<p>
<pre>
<code style="font-family: Courier New, Courier, monospace; font-size: 12">
* @jsp.variable name-given="currentIter"
* class="java.lang.Integer" scope="NESTED"
* @jsp.variable name-given="atBegin"
* class="java.lang.Integer" scope="AT_BEGIN"
* @jsp.variable name-given="atEnd"
* class="java.lang.Integer" scope="AT_END"
</code>
</pre>
</p>
<p>XDoclet 的另一个好处是它使这个定制标记构成的所有东西被保存在一个文件中。此外，它也很适合于记录构成这个定制标记的东西。想想如果不用 XDoclet，您必须在长长的 TLD 文件中寻找正确的条目（<i>struts-html.tld</i> 文件长达 3000 行！）才能了解这个标记定义的变量。</p>
<p>这段代码在 TLD 文件的基本标记定义中生成以下代码：
<pre>
<code style="font-family: Courier New, Courier, monospace; font-size: 12">
</p><p>
<variable>
<name-given>currentIter</name-given>
<variable-class>java.lang.Integer</variable-class>
<scope>NESTED</scope>
</variable>
<variable>
<name-given>atBegin</name-given>
<variable-class>java.lang.Integer</variable-class>
<scope>AT_BEGIN</scope>
</variable>
<variable>
<name-given>atEnd</name-given>
<variable-class>java.lang.Integer</variable-class>
<scope>AT_END</scope>
</variable>
</code>
</pre>
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