XSLT模板和递归

Question

我是XSLT的新手,在尝试格式化具有递归节点的XML文档时遇到了一些问题.

我的XML代码:

希望我的XML显示:

• 所有<item>都嵌套着<items>
• 项可以只有属性或子节点
• <item>嵌套节点的级别可能非常深

<?xml version="1.0" encoding="utf-8" ?> 
- <items>
  <item groupID="1" name="Home" url="//" /> 
- <item groupID="2" name="Guides" url="/Guides/">
- <items>
- <item groupID="26" name="Online-Poker-Guide" url="/Guides/Online-Poker-Guide/">
- <items>
- <item>
  <id>107</id> 
- <title>
- <![CDATA[ Poker Betting - Online Poker Betting Structures
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/online-poker-betting-structures
  ]]> 
  </url>
  </item>
- <item>
  <id>114</id> 
- <title>
- <![CDATA[ Beginners&#39; Poker - Poker Hand Ranking
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/online-poker-hand-ranking
  ]]> 
  </url>
  </item>
- <item>
  <id>115</id> 
- <title>
- <![CDATA[ Poker Terms - 4th Street and 5th Street
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/online-poker-poker-terms
  ]]> 
  </url>
  </item>
- <item>
  <id>116</id> 
- <title>
- <![CDATA[ Popular Poker - The Popularity of Texas Hold&#39;em
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/online-poker-popularity-texas-holdem
  ]]> 
  </url>
  </item>
- <item>
  <id>364</id> 
- <title>
- <![CDATA[ The Impact of Traditional Poker on Online Poker (and vice versa)
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/online-poker-tradional-vs-online
  ]]> 
  </url>
  </item>
- <item>
  <id>365</id> 
- <title>
- <![CDATA[ The Ultimate, Absolute Online Poker Scandal
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/online-poker-scandal
  ]]> 
  </url>
  </item>
  </items>
- <items>
- <item groupID="27" name="Beginners-Poker" url="/Guides/Online-Poker-Guide/Beginners-Poker/">
- <items>
+ <item>
  <id>101</id> 
- <title>
- <![CDATA[ Poker Betting - All-in On the Flop
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/poker-betting-all-in-on-the-flop
  ]]> 
  </url>
  </item>
+ <item>
  <id>102</id> 
- <title>
- <![CDATA[ Beginners&#39; Poker - Choosing an Online Poker Room
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/beginners-poker-choosing-a-room
  ]]> 
  </url>
  </item>
+ <item>
  <id>105</id> 
- <title>
- <![CDATA[ Beginners&#39; Poker - Choosing What Type of Poker to Play
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/beginners-poker-choosing-type-to-play
  ]]> 
  </url>
  </item>
+ <item>
  <id>106</id> 
- <title>
- <![CDATA[ Online Poker - Different Types of Online Poker
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/online-poker
  ]]> 
  </url>
  </item>
+ <item>
  <id>109</id> 
- <title>
- <![CDATA[ Online Poker - Opening an Account at an Online Poker Site
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/online-poker-opening-an-account
  ]]> 
  </url>
  </item>
+ <item>
  <id>111</id> 
- <title>
- <![CDATA[ Beginners&#39; Poker - Poker Glossary
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/beginners-poker-glossary
  ]]> 
  </url>
  </item>
+ <item>
  <id>117</id> 
- <title>
- <![CDATA[ Poker Betting - What is a Blind?
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/poker-betting-what-is-a-blind
  ]]> 
  </url>
  </item>
- <item>
  <id>118</id> 
- <title>
- <![CDATA[ Poker Betting - What is an Ante?
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/poker-betting-what-is-an-ante
  ]]> 
  </url>
  </item>
+ <item>
  <id>119</id> 
- <title>
- <![CDATA[ Beginners Poker - What is Bluffing?
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/online-poker-what-is-bluffing
  ]]> 
  </url>
  </item>
- <item>
  <id>120</id> 
- <title>
- <![CDATA[ Poker Games - What is Community Card Poker?
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/online-poker-what-is-community-card-poker
  ]]> 
  </url>
  </item>
- <item>
  <id>121</id> 
- <title>
- <![CDATA[ Online Poker - What is Online Poker?
  ]]> 
  </title>
- <url>
- <![CDATA[ /Guides/Online-Poker-Guide/Beginners-Poker/online-poker-what-is-online-poker
  ]]> 
  </url>
  </item>
  </items>
  </item>
  </items>
  </item>
  </items>
  </item>
  </items>

XSL代码:

<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="html" indent="yes"/>

    <xsl:template name="loop">
        <xsl:for-each select="items/item">
            <ul>
            <li><xsl:value-of select="@name" /></li>
            <xsl:if test="@name and child::node()">
                <ul>
                    <xsl:for-each select="items/item">
                        <li><xsl:value-of select="@name" />test</li>
                    </xsl:for-each>
                </ul>
                <xsl:call-template name="loop" />
            </xsl:if>
            <xsl:if test="child::node() and not(@name)">
                <xsl:for-each select="/items">
                    <li><xsl:value-of select="id" /></li>
                </xsl:for-each>
            </xsl:if>
            </ul>
        </xsl:for-each>
        <xsl:for-each select="item/items/item">
            <li>hi</li>
        </xsl:for-each>
    </xsl:template>

    <xsl:template match="/" name="test">
            <xsl:call-template name="loop" />
    </xsl:template>

</xsl:stylesheet>

我试图编写XSL,以便每个<items>节点都渲染一个<ul>,每个<items>节点都会呈现一个<li>.

XSL需要递归,因为我无法知道嵌套节点的深度.

有人可以帮忙吗？

此致,Al

Answer 1

这很简单.XSLT处理器为您完成所有递归和循环,您需要做的就是为要处理的节点指定模板.

<xsl:stylesheet 
  version="1.0" 
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
>
  <!-- <items> with <item> children becomes <ul> -->
  <xsl:template match="items[item]">
    <ul>
      <xsl:apply-templates select="item" />
    </ul>
  </xsl:template>

  <!-- <items> without <item> children is not handled -->
  <xsl:template match="items[not(item)]" />

  <!-- <item> with @name becomes <li> -->
  <xsl:template match="item[@name]">
    <li>
      <xsl:value-of select ="@name" />
      <xsl:apply-templates select="items" />
    </li>
  </xsl:template>

  <!-- <item> without @name becomes <li>, too -->
  <xsl:template match="item[not(@name)]">
    <li>
      <xsl:value-of select ="id" />
      <xsl:apply-templates select="items" />
    </li>
  </xsl:template>
</xsl:stylesheet>

该<xsl:apply-templates>总是在XSLT递归/迭代步.它需要适合其select表达式的任何节点并为它们找到模板.

你的工作就是制作一个合适的select表达式,为你想要处理的每个节点提供一个模板,否则就会让它失控.;-)抵制将所有东西塞进一个大模板的冲动,或<xsl:for-each>仅仅因为感觉方便而使用 - 事实并非如此.单独的模板创建了更多可重用且可维护,嵌套程度较低的代码,并且XSLT处理器针对模板处理进行了优化,因此这甚至可能是更有效的方法.

Answer 2

如果我正确理解您的需求，您应该能够在不编写循环的情况下执行此操作。

通常最好使用更具声明性的样式，在这种情况下，编写一个与<items>标签匹配的模板并将其转换为 a <ul>，另一个匹配<item>将其转换为 a <li>。<xsl:apply-templates/>两个模板内的调用将提供递归。