xslt - 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文档时遇到一些问题。

我的XML代码：

希望我的XML显示：


所有<item>都嵌套有<items>
一个项目可以仅具有属性，也可以具有子节点
嵌套<item>节点的级别可以无限深

<?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>节点将呈现一个 <ul>，而每个 <items>节点将呈现一个 <li>。

XSL需要是递归的，因为我无法告诉嵌套节点的深度。

有人可以帮忙吗？

问候，
铝

Answer 1

这很简单。 XSLT处理器为您完成所有递归和循环，您所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>

<xsl:apply-templates>始终是XSLT中的递归/迭代步骤。它采用适合其 select表达式的所有节点并为其找到模板。

您的工作是制作一个合适的 select表达式，为您要处理的每个节点提供一个模板，否则就避免了。 ;-)抵制将所有内容塞入一个大模板或使用 <xsl:for-each>只是因为感觉很方便的冲动-事实并非如此。单独的模板可创建更多可重用和可维护的，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。