J2EE—— 第 7 章 Extensible Stylesheet Language Transformations (XSL

T)

XSL 、 XSLT 和 XPath 简介 XSL-FO: 字体大小、页面布局、对象显示 XSLT: 从 XML 到某种其它格式的转换 XPath: 指定通向某个元素的路径 javax.xml.transform javax.xml.transform.dom javax.xml.transform.sax javax.xml.transform.stream

XPath 如何工作 XPath 规范定义了一个抽象文档模型，该

文档模型定义了几种类型的节点： Root, Element,Text, Attribute,Comment Processing instruction, Namespace

XSLT/XPath 数据模型 : 包含各种节点的树<xsl:template match="//LIST"> ... </xsl:template>

基本 XPath 寻址 正斜杠 (/) 用作路径分隔符 从文档的根开始的绝对路径以 / 开始 从指定位置开始的相对路径可以以任何

其它符号开始 双句点 (..) 表示当前节点的父节点 单句点 (.) 表示当前节点

基本 XPath 表达式 PROJECT[.=“MyProject”] PROJECT[STATUS] PROJECT[STATUS=“Critical”] LIST[@type=“ordered”][3] LIST[3][@type=“ordered”] * 匹配任何 Element 节点 node() 匹配任何类型的任何节点 @* 匹配任何属性节点 /HEAD/LIST//PARA

XPath 数据类型和运算符

元素的字符串值<PARA>This paragraph contains a <B>bold</B>

word</PARA> PARA/text() This paragraph contains a bold word

XPath 函数 节点集函数

id(…) 位置函数

last() ：如 /HEAD[last()] position() ：如 /HEAD[position()<=5] count(…) ：如 /HEAD[count(HEAD)=0]

字符串函数 concat(string, string, ...): contains(string1, string2 substring-before(string1, string2) substring-after(string1, string2) substring(string, idx) substring(string, idx, len) string-length() string-length(string) normalize-space() normalize-space(string) translate(string1, string2, string3):

其它函数 Boolean 函数

not(...) true() false() lang(string)

数值函数 sum(…) floor(N) ceiling(N) round(N)

其它函数 转换函数

string(…) boolean(…) number(…)

名称空间函数 local-name(), local-name(…) namespace-uri(), namespace-uri(..) name(), name(…)

把 DOM 作为 XML 文件写出import javax.xml.transform.Transformer; import javax.xml.transform.TransformerFactory;import javax.xml.transform.TransformerException; import javax.xml.transform.TransformerConfigurationExceptio

n; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult;

TransformerFactory tFactory =TransformerFactory.newInstance();

Transformer transformer = tFactory.newTransformer(); DOMSource source = new DOMSource(document);StreamResult result = new StreamResult(System.out);transformer.transform(source, result);

写出 DOM 的子树import org.w3c.dom.Node;import org.w3c.dom.NodeList;NodeList list = document.getElementsByTagName("sl

ide");Node node = list.item(0);DOMSource source = new DOMSource(node);

<?xml version="1.0" encoding="UTF-8"?> <slide type="all">

<title>Wake up to WonderWidgets!</title> </slide>

从任一数据结构生成 XMLxmozillanickname: Fredmail: Fred@barneys.housexmozillausehtmlmail: TRUEgivenname: Fredsn: Flintstonetelephonenumber: 999-Quarryhomephone: 999-BedrockLanefacsimiletelephonenumber: 888-Squawkpagerphone: 777-pagercellphone: 555-cell

准备工作import org.xml.sax.*;import org.xml.sax.helpers.AttributesImpl;public class AddressBookReader implements XMLReader {

ContentHandler handler; String nsu = ""; // NamespaceURIAttributes atts = new AttributesImpl(); String rootElement = "addressbook"; String indent = "\n "; // for readability! public void parse (InputSource input) throws IOException, SAXExcepti

on{java.io.Reader r = input.getCharacterStream(); BufferedReader br = new BufferedReader(r);

生成 SAX 事件if (handler==null) {

throw new SAXException("No content handler"); } handler.startDocument(); handler.startElement(nsu, rootElement, rootElement, atts); output("nickname", "xmozillanickname", line);line = br.readLine();...output("cell", "cellphone", line);handler.ignorableWhitespace("\n".toCharArray(), 0, 1); handler.endElement(nsu, rootElement, rootElement);handler.endDocument();

元素 SAX 事件void output(String name, String prefix, String line) throws SAXExceptio

n {int startIndex = prefix.length() + 2; // 2=length of ": " String text = line.substring(startIndex); int textLength = line.length() - startIndex; handler.ignorableWhitespace(indent.toCharArray(), 0, indent.lengt

h());handler.startElement(nsu, name, name /*"qName"*/, atts); handler.characters(text.toCharArray(), startIndex, textLength);handler.endElement(nsu, name, name);

}

把解析器用作 SAXSourceimport org.xml.sax.ContentHandler;import org.xml.sax.InputSource;import javax.xml.transform.sax.SAXSource; AddressBookReader saxReader = new AddressBookReader(); Transformer transformer = tFactory.newTransformer();FileReader fr = new FileReader(f);BufferedReader br = new BufferedReader(fr);InputSource inputSource = new InputSource(br);SAXSource source = new SAXSource(saxReader, inputSource);StreamResult result = new StreamResult(System.out);transformer.transform(source, result);

用 XSLT 转换 XML 数据<?xml version="1.0"?> <ARTICLE>

<TITLE>A Sample Article</TITLE><SECT>The First Major Section

<PARA>This section will introduce a subsection.</PARA>

<SECT>The Subsection Heading<PARA>This is the text of the subsection. </PARA>

</SECT></SECT>

</ARTICLE>

编写 XSLT 转换<?xml version="1.0" encoding="ISO-8859-1"?> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"version="1.0">

<xsl:output method="html"/><xsl:template match="/"> <html><body>

<xsl:apply-templates/> </body></html> </xsl:template> …

</xsl:stylesheet> 使用 html 输出方式时 , &lt; 将输出为 <

处理 <TITLE> 和 <SECT><xsl:template match="/ARTICLE/TITLE">

<h1 align="center"><xsl:apply-templates/></h1> </xsl:template> <xsl:template match="/ARTICLE/SECT">

<h2><xsl:apply-templates select="text()|B|I|U|DEF|LINK"/></h2> <xsl:apply-templates select="SECT|PARA|LIST|NOTE"/>

</xsl:template> <xsl:template match="/ARTICLE/SECT/SECT">

<h3><xsl:apply-templates select="text()|B|I|U|DEF|LINK"/></h3> <xsl:apply-templates select="SECT|PARA|LIST|NOTE"/>

</xsl:template></xsl:stylesheet>

处理过深嵌套错误和 <PARA><xsl:template match="/ARTICLE/SECT/SECT/SECT">

<xsl:message terminate="yes">Error: Sections can only be nested 2 deep.</xsl:message>

</xsl:template><xsl:template match="PARA">

<p><xsl:apply-templates/></p></xsl:template></xsl:stylesheet>

编写基本的程序import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamSource; import javax.xml.transform.stream.StreamResult;File stylesheet = new File(argv[0]);File datafile = new File(argv[1]);DocumentBuilder builder = factory.newDocumentBuilder(); document = builder.parse(datafile); StreamSource stylesource = new StreamSource(stylesheet); Transformer transformer = Factory.newTransformer(stylesource);DOMSource source = new DOMSource(document);StreamResult result = new StreamResult(System.out);transformer.transform(source, result);

转换结果<html><body>

<h1 align="center">A Sample Article</h1><h2>The First Major Section

</h2><p>This section will introduce a subsection.</p><h3>The Subsection Heading

</h3><p>This is the text of the subsection.

</p>

</body></html>

剪裁空白<xsl:strip-space elements="SECT"/> <xsl:template match="text()">

<xsl:value-of select="normalize-space()"/></xsl:template>

<html><body><h1 align="center">A Sample Article</h1><h2>The First Major Section</h2><p>This section will introduce a subsection.</p><h3>The Subsection Heading</h3><p>This is the text of the subsection.</p></body></html>

处理其余的结构元素<?xml version="1.0"?> <ARTICLE>

<TITLE>A Sample Article</TITLE><SECT>The First Major Section...</SECT><SECT>The Second Major Section

<PARA>This section adds a LIST and a NOTE. </PARA><PARA>Here is the LIST:

<LIST type="ordered"><ITEM>Pears</ITEM><ITEM>Grapes</ITEM>

</LIST></PARA><PARA>And here is the NOTE:

<NOTE>Don't forget to go to the hardware store on your way to the grocery!

</NOTE> </PARA>

</SECT> </ARTICLE>

修改 XSLT<xsl:template match="PARA">

<p><xsl:apply-templates select="text()|B|I|U|DEF|LINK"/></p><xsl:apply-templates select="PARA|LIST|NOTE"/>

</xsl:template><xsl:template match="LIST">

<xsl:if test="@type='ordered'"> <ol>

<xsl:apply-templates/></ol>

</xsl:if> <xsl:if test="@type='unordered'">

<ul><xsl:apply-templates/>

</ul></xsl:if>

</xsl:template></xsl:stylesheet>

处理 <ITEM> 和 <NOTE><xsl:template match="ITEM">

<li><xsl:apply-templates/> </li>

</xsl:template> <xsl:template match="NOTE">

<blockquote><b>Note:</b><br/> <xsl:apply-templates/>

</blockquote> </xsl:template> 当多个模板都匹配时，最后出现的模板优先

运行结果…<h2>The Second Major Section</h2><p>This section adds a LIST and a NOTE.</p><p>Here is the LIST:</p><ol><li>Pears</li><li>Grapes</li></ol><p>And here is the NOTE:</p><blockquote><b>Note:</b><br>Don't forget to go to the hardware store on your way to thegrocery!</blockquote>

处理内联 ( 内容 ) 元素<SECT>The <I>Third</I> Major Section

<PARA>In addition to the inline tag in the heading, this section defines the term <DEF>inline</DEF>, which literally means "no line break". It also adds a simple link to the main page for the Java platform (<LINK>http://java.sun.com</LINK>), as well as a link to the <LINK target="http://java.sun.com/xml">XML</LINK> page.

</PARA></SECT>

修改 XSLT<xsl:template match="DEF">

<i><xsl:apply-templates/></i></xsl:template>

<xsl:template match="B|I|U"><xsl:element name="{name()}"><xsl:apply-templates/></xsl:element>

</xsl:template>

处理 <LINK><xsl:template name="htmLink">

<xsl:param name="dest" select="UNDEFINED"/><xsl:element name="a">

<xsl:attribute name="href"> <xsl:value-of select="$dest"/>

</xsl:attribute><xsl:apply-templates/>

</xsl:element></xsl:template>

调用命名模板<xsl:template match="LINK">

<xsl:if test="@target"><xsl:call-template name="htmLink">

<xsl:with-param name="dest" select="@target"/></xsl:call-template></xsl:if><xsl:if test="not(@target)">

<xsl:call-template name="htmLink"><xsl:with-param name="dest">

<xsl:apply-templates/></xsl:with-param>

</xsl:call-template></xsl:if>

</xsl:template>

运行结果...<h2>The <I>Third</I> Major Section</h2>

<p>In addition to the inline tag in the heading, this section defines the term <i>inline</i>, which literally means "no line break". It also adds a simple link to the main page for the Java platform (<a href="http://java. sun.com">http://java.sun.com</a>), as well as a link to the <a href="http://java.sun.com/xml">XML</a> page.

</p>

XSLT 的其它功能 include, import for-each 生成编号 格式化编号 输出排序 基于模式的模板<apply-template mode=“…”>

用 Xalan 从命令行转换java org.apache.xalan.xslt.Process-IN article3.xml -XSL article3.xsl-OUT article3.html

用过滤器链连接转换File stylesheet1 = new File(argv[0]);File stylesheet2 = new File(argv[1]);File datafile = new File(argv[2]);BufferedInputStream bis = new BufferedInputStream(newFileInputStream(dataf

ile));InputSource input = new InputSource(bis);SAXParserFactory.newInstance(); spf.setNamespaceAware(true);SAXParser parser = spf.newSAXParser();XMLReader reader = parser.getXMLReader();SAXTransformerFactory stf = (SAXTransformerFactory) TransformerFactory.newI

nstance(); XMLFilter filter1 = stf.newXMLFilter( new StreamSource(stylesheet1)); XMLFilter filter2 = stf.newXMLFilter( new StreamSource(stylesheet2));filter1.setParent(reader);filter2.setParent(filter1);StreamResult result = new StreamResult(System.out); Transformer transformer = stf.newTransformer(); SAXSource transformSource = new SAXSource(filter2, input);transformer.transform(transformSource, result);

了解过滤器如何工作

测试程序<?xml version="1.0"?><Article>

<ArtHeader><Title>Title of my (Docbook) article</Title>

</ArtHeader><Sect1>

<Title>Title of Section 1.</Title><Para>This is a paragraph.</Para>

</Sect1></Article>

作为 filter1 的 xsl 文件<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform“ v

ersion="1.0“><xsl:output method="xml"/><xsl:template match="/">

<ARTICLE><xsl:apply-templates/>

</ARTICLE></xsl:template><xsl:template match="/Article/ArtHeader/Title">

<TITLE> <xsl:apply-templates/> </TITLE></xsl:template> <xsl:template match="//Sect1">

<SECT><xsl:apply-templates/></SECT></xsl:template> <xsl:template match="Para">

<PARA><xsl:apply-templates/></PARA></xsl:template>

</xsl:stylesheet>

过滤器链连接转换结果<html><body><h1 align="center">Title of my (Docbook) article</h1><h2>Title of Section 1.</h2><p>This is a paragraph.</p></body></html>