XSLT:reocurring xpath的缩写

时间:2012-08-31 20:00:00

标签: xslt xpath xslt-1.0

在XSL转换中,我有一个相当冗长的XPath(大约20个不同节点的联合)。因为经常需要这条路径,所以它的缩写会很好。

缩写必须以在当前上下文中进行评估的方式进行,因此使用全局变量或某些东西将无效。

目标版本是带有EXSLT扩展的XSLT 1.0。

谢谢,
斯特

2 个答案:

答案 0 :(得分:3)

如果您不能拥有全局变量,那么function可能就是解决方案。

答案 1 :(得分:1)

您可以使用实体提供冗长的XPath的缩写

XSLT是一个XML文件,因此可以在XSLT中的任何位置使用XML实体。在解析XSLT时,将扩展和解析实体。

使用全局XSLT变量无法实现的实体可以使用XPath中的实体并匹配表达式。

例如,您可以为长XPath语句创建一个实体,并在多个位置重复使用它,如下所示:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE stylesheet [
<!ENTITY lengthyXPath "elem1 | elem2 | elem3 | elem4 | elem5 | elem6 | elem7 | elem8 | elem9 | elem10 | elem11 | elem12 | elem13 | elem14 | elem15 | elem16 | elem17 | elem18 | elem19 | elem20">
]>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    version="1.0">
    <xsl:output indent="yes"/>
    <xsl:template match="/">
        <output>
           <xsl:apply-templates select="/*/*"/>     
        </output>
    </xsl:template>

    <xsl:template match="foo">
            <xsl:comment>mached foo child elements from: &lengthyXPath;</xsl:comment>
            <xsl:apply-templates select="&lengthyXPath;"/>
    </xsl:template>

    <xsl:template match="bar">
            <xsl:comment>mached bar child elements from: &lengthyXPath;</xsl:comment>
            <xsl:apply-templates select="&lengthyXPath;"/>
    </xsl:template>

    <xsl:template match="baz">
            <xsl:comment>mached baz child elements from: &lengthyXPath;</xsl:comment>
            <xsl:apply-templates select="&lengthyXPath;"/>
    </xsl:template>

    <xsl:template match="&lengthyXPath;">
        <xsl:copy-of select="."/>
    </xsl:template>

</xsl:stylesheet>

应用于此XML时:

 <doc>
    <foo>
        <elem>no match</elem>
        <elem1>1</elem1>
        <elem>no match</elem>
        <elem3>3</elem3>
        <elem>no match</elem>
        <elem5>5</elem5>
    </foo>
    <bar>
        <elem>no match</elem>
        <elem7>7</elem7>
        <elem>no match</elem>
        <elem9>9</elem9>
        <elem>no match</elem>
        <elem10>10</elem10>
    </bar>
    <baz>
        <elem>no match</elem>
        <elem11>11</elem11>
        <elem>no match</elem>
        <elem13>13</elem13>
        <elem>no match</elem>
        <elem15>15</elem15>
    </baz>
</doc>

产生以下输出:

<?xml version="1.0" encoding="UTF-8"?>
<output><!--mached foo child elements from: elem1 | elem2 | elem3 | elem4 | elem5 | elem6 | elem7 | elem8 | elem9 | elem10 | elem11 | elem12 | elem13 | elem14 | elem15 | elem16 | elem17 | elem18 | elem19 | elem20--><elem1>1</elem1>
   <elem3>3</elem3>
   <elem5>5</elem5>
   <!--mached bar child elements from: elem1 | elem2 | elem3 | elem4 | elem5 | elem6 | elem7 | elem8 | elem9 | elem10 | elem11 | elem12 | elem13 | elem14 | elem15 | elem16 | elem17 | elem18 | elem19 | elem20--><elem7>7</elem7>
   <elem9>9</elem9>
   <elem10>10</elem10>
   <!--mached baz child elements from: elem1 | elem2 | elem3 | elem4 | elem5 | elem6 | elem7 | elem8 | elem9 | elem10 | elem11 | elem12 | elem13 | elem14 | elem15 | elem16 | elem17 | elem18 | elem19 | elem20--><elem11>11</elem11>
   <elem13>13</elem13>
   <elem15>15</elem15>
</output>