xsl本身就是一个构型良好的xml，它能够把一个xml文档转换成另外一个xml文档，或者转换成文本文件、html文件等等。这里就是利用xsl来动态的生成我们想要的java文件（从某种角度看，java代码其实也就是一个文本文件），希望能够通过这篇文章，看到xml以及相关的技术所具有的强大能力！

这里首先给一个xml例子，我们将通过一个xsl从该xml文件中抽取有用的信息来生成java代码（实际上是一个javabean）：

以下内容为程序代码: <?xml version="1.0" encoding="ISO-8859-1" ?> <bean> <name>Product</name> <comments>This bean represents a product that the company offers to its customers</comments> <property> <name>code</name> <type>int</type> <comments>the product inventory code</comments> </property> <property> <name>name</name> <type>String</type> <comments>the product name</comments> </property> <property> <name>testedOnAnimals</name> <type>boolean</type> <comments>the flag that indicates if the product was tested on animals</comments> </property> <property> <name>availableSince</name> <type>java.util.Date</type> <comments>the date when the company started offering this product to its customers</comments> </property> </bean>

下面我就直接给出转换的xsl，如果大家对xsl不是很了解的话，可以先看一些资料，了解之后就会明白了。我在里面稍微做了些注释：

以下内容为程序代码: <?xml version="1.0"?> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"  xmlns:java="http://xml.apache.org/xslt/java" exclude-result-prefixes="java"> <!--这里就是指定通过这个xsl所转换的结果的类型，是text格式--> <xsl:output method = "text"/> <!--xslt使用模版来处理xml中的节点--> <xsl:template match="bean"> /** * <xsl:value-of select="comments"/>//这里是获取xml文档中的节点值 * This class has been generated by the XSLT processor from the metadata */ public class <xsl:value-of select="name"/> { /**  * Creates a new instance of the <xsl:value-of select="name"/> bean  */ public <xsl:value-of select="name"/>() {}   <xsl:apply-templates select="property"/> } </xsl:template> <xsl:template match="property"> private <xsl:value-of select="type"/> <xsl:text> </xsl:text>//输出文本，这里是输出一个空格 <xsl:value-of select="name"/>; <xsl:variable name="name" select="name"/>//定义xsl中要使用的变量 <xsl:variable name="cname" select="java:Capitalizer.capitalize($name)"/>//这里使用了xslt extensions，它可以允许在xslt中直接引用java中方法，非常方便。 /**  * Sets <xsl:value-of select="comments"/>  * @param <xsl:value-of select="name"/> is <xsl:value-of select="comments"/>  */ public void set<xsl:value-of select="$cname"/>(<xsl:value- of select="type"/> <xsl:text> </xsl:text><xsl:value- of select="name"/>) { this.<xsl:value-of select="name"/> = <xsl:value-of select="name"/>; } /**  * Returns <xsl:value-of select="comments"/>  * @return <xsl:value-of select="comments"/>  */ public <xsl:value-of select="type"/><xsl:text></xsl:text> <xsl:apply-templates select="type"/><xsl:value-of select="$cname"/>() { return <xsl:value-of select="name"/>; } </xsl:template> <xsl:template match="type"> <xsl:variable name="type" select="."/> <xsl:choose> <xsl:when test="$type='boolean'">is</xsl:when> <xsl:otherwise>get</xsl:otherwise> </xsl:choose> </xsl:template> </xsl:stylesheet>

好了，完成以上工作之后，只要在cmd中，输入如下的命令行，就可以获得我们想要的结果了：
java org.apache.xalan.xslt.Process -in xmlSource-xsl stylesheet -out outputfile

这里列出结果：

以下内容为程序代码: /** * This bean represents a product that the company offers to its customers * This class has been generated by the XSLT processor from the metadata */ public class Product { /**  * Creates a new instance of the Product bean  */ public Product() {}     private int code;   /**  * Sets the product inventory code  * @param code is the product inventory code  */ public void setCode(int code) { this.code = code; } /**  * Returns the product inventory code  * @return the product inventory code  */ public int getCode() { return code; } private String name;   /**  * Sets the product name  * @param name is the product name  */ public void setName(String name) { this.name = name; } /**  * Returns the product name  * @return the product name  */ public String getName() { return name; } private boolean testedOnAnimals;   /** * Sets the flag that indicates if the product was tested on animals * @param testedOnAnimals is the flag that indicates if the product was tested on animals */ public void setTestedOnAnimals(boolean testedOnAnimals) { this.testedOnAnimals = testedOnAnimals; } /**  * Returns the flag that indicates if the product was tested on animals  * @return the flag that indicates if the product was tested on animals  */ public boolean isTestedOnAnimals() { return testedOnAnimals; } private java.util.Date availableSince;   /**  * Sets the date when the company started offering this product to its customers  * @param availableSince is the date when the company started offering this product to its customers  */ public void setAvailableSince(java.util.Date availableSince) { this.availableSince = availableSince; } /**  * Returns the date when the company started offering this product to its customers  * @return the date when the company started offering this product to its customers  */ public java.util.Date getAvailableSince() { return availableSince; } }

总结：
1. 在熟悉了xsl的基本使用之后，理解以上的内容并不是困难；
2. 这样做是比较适合预先知道了某些逻辑功能，但由于某种原因，需要动态生成，或者是为了节省不必要的重复工作，可以通过它自动生成代码；
3. 修改这个xsl比较方便。

sjoy