【0】README1）本文旨在 给出 利用ant构建 jsp->servlet->class->jar 的分析；2）本文部分内容转自：/blog/757919
【1】ant脚本内容 及其分析1）build.xml
<?xml version="1.0" encoding="UTF-8"?><project name="webNews" basedir="." default="servlet2class"><property file="build.properties" /><target name="all" depends="jsp2servlet,servlet2class,class2jar" /><target name="help"><echo message="显示功能列表" /><echo message="jsp2java 通过JspC将JSP转换成Java源代码" /><echo message="java2class 将转换后的Java源代码进行编译成class文件" /><echo message="class2jar 将编译后的class文件打包" /><echo message="clear 清理现场" /></target><target name="jsp2servlet"><taskdef classname="org.apache.jasper.JspC" name="jsp2java"><classpath id="jsp2servlet.classpath"><fileset dir="${tomcat.home}/bin"><include name="*.jar" /></fileset><fileset dir="${tomcat.home}/lib"><include name="*.jar" /></fileset></classpath></taskdef><jsp2javaclasspath="jsp2java.classpath" javaEncoding="UTF-8" validateXml="false" uriroot="${webapp.path}/WebRoot" webXmlFragment="${webapp.path}/WebRoot/WEB-INF/webJSP.xml"webXml="${webapp.path}/WebRoot/WEB-INF/web.xml"outputDir="${webapp.path}/WebRoot/WEB-INF/JspC/src" /></target><target name="servlet2class"><mkdir dir="${webapp.path}/WebRoot/WEB-INF/JspC/classes" /><javac srcdir="${webapp.path}/WebRoot/WEB-INF/JspC/src" destdir="${webapp.path}/Webroot/WEB-INF/JspC/classes" encoding="utf-8" optimize="off" debug="on" failοnerrοr="false" excludes="**/*.smap"><classpath id="java2class.classpath"><fileset dir="${webapp.path}/WebRoot/WEB-INF/lib"><include name="*.jar" /></fileset><fileset dir="${tomcat.home}/lib"><include name="*.jar" /></fileset><fileset dir="${tomcat.home}/bin"><include name="*.jar" /></fileset><pathelement location="${webapp.path}/WebRoot/WEB-INF/classes" /></classpath></javac></target><target name="class2jar"><!-- <mkdir dir="${webapp.path}/WebRoot/WEB-INF/lib" /> --><jar jarfile="${webapp.path}/WebRoot/WEB-INF/lib/${webapp.name}JSP.jar" basedir="${webapp.path}/Webroot/WEB-INF/JspC/classes" /></target><target name="clear"><delete dir="${webapp.path}/WebRoot/WEB-INF/JspC/src" /><delete dir="${webapp.path}/Webroot/WEB-INF/JspC/classes" /><delete dir="${webapp.path}/WebRoot/WEB-INF/lib/${webapp.name}JSP.jar"></delete></target></project>
2）build.properties
#tomcat hometomcat.home=D:\\Development\\Tomcat\\apache-tomcat-8.0.36webapp.path=E:\\bench-cluster\\spring_in_action_eclipse\\precompileJSPwebapp.name=precompileJSP
对以上ant 脚本的分析（Analysis）
A1）jsp->servlet：（将jsp 转换为 servlet——特殊的java类）
<target name="jsp2servlet"><taskdef classname="org.apache.jasper.JspC" name="jsp2java"><classpath id="jsp2servlet.classpath"><fileset dir="${tomcat.home}/bin"><include name="*.jar" /></fileset><fileset dir="${tomcat.home}/lib"><include name="*.jar" /></fileset></classpath></taskdef><jsp2javaclasspath="jsp2java.classpath" javaEncoding="UTF-8" validateXml="false" uriroot="${webapp.path}/WebRoot" webXmlFragment="${webapp.path}/WebRoot/WEB-INF/webJSP.xml"webXml="${webapp.path}/WebRoot/WEB-INF/web.xml"outputDir="${webapp.path}/WebRoot/WEB-INF/JspC/src" /></target>org.apache.jasper.JspC 的属性设置，参见 /tomcat-8.0-doc/api/org/apache/jasper/JspC.html；
Attention）注意上述目录生成的 web.xml， 该文件设置了 servlet 到 uri 的 映射
<?xml version="1.0" encoding="ISO-8859-1"?><!DOCTYPE web-appPUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN""/dtd/web-app_2_3.dtd"><!--Automatically created by Apache Tomcat JspC.--><web-app><servlet><servlet-name>org.apache.jsp.home_jsp</servlet-name><servlet-class>org.apache.jsp.home_jsp</servlet-class></servlet><servlet><servlet-name>org.apache.jsp.views.home_jsp</servlet-name><servlet-class>org.apache.jsp.views.home_jsp</servlet-class></servlet><servlet-mapping><servlet-name>org.apache.jsp.home_jsp</servlet-name><url-pattern>/home.jsp</url-pattern></servlet-mapping><servlet-mapping><servlet-name>org.apache.jsp.views.home_jsp</servlet-name><url-pattern>/views/home.jsp</url-pattern></servlet-mapping></web-app>A2）servlet->class：（将 servlet 文件编译为 class文件）
<target name="servlet2class"><mkdir dir="${webapp.path}/WebRoot/WEB-INF/JspC/classes" /><javac srcdir="${webapp.path}/WebRoot/WEB-INF/JspC/src" destdir="${webapp.path}/Webroot/WEB-INF/JspC/classes" encoding="utf-8" optimize="off" debug="on" failοnerrοr="false" excludes="**/*.smap"><classpath id="java2class.classpath"><fileset dir="${webapp.path}/WebRoot/WEB-INF/lib"><include name="*.jar" /></fileset><fileset dir="${tomcat.home}/lib"><include name="*.jar" /></fileset><fileset dir="${tomcat.home}/bin"><include name="*.jar" /></fileset><pathelement location="${webapp.path}/WebRoot/WEB-INF/classes" /></classpath></javac></target>A3）class->jar：（将 上述编译得到的 class 文件打包为 jar）
<target name="class2jar"><!-- <mkdir dir="${webapp.path}/WebRoot/WEB-INF/lib" /> --><jar jarfile="${webapp.path}/WebRoot/WEB-INF/lib/${webapp.name}JSP.jar" basedir="${webapp.path}/Webroot/WEB-INF/JspC/classes" /></target>
A4）清理临时文件工作
<target name="clear"><delete dir="${webapp.path}/WebRoot/WEB-INF/JspC/src" /><delete dir="${webapp.path}/Webroot/WEB-INF/JspC/classes" /><delete dir="${webapp.path}/WebRoot/WEB-INF/lib/${webapp.name}JSP.jar"></delete></target>
【2】windows 下执行上述命令的 console info
E:\bench-cluster\spring_in_action_eclipse\precompileJSP>ant jsp2servletBuildfile: E:\bench-cluster\spring_in_action_eclipse\precompileJSP\build.xmljsp2servlet:[jsp2java] 七月 08, 2:31:24 下午 org.apache.jasper.servlet.TldScanner scanJars[jsp2java] 信息: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.BUILD SUCCESSFULTotal time: 0 secondsE:\bench-cluster\spring_in_action_eclipse\precompileJSP>ant servlet2classBuildfile: E:\bench-cluster\spring_in_action_eclipse\precompileJSP\build.xmlservlet2class:[mkdir] Created dir: E:\bench-cluster\spring_in_action_eclipse\precompileJSP\WebRoot\WEB-INF\JspC\classes[javac] E:\bench-cluster\spring_in_action_eclipse\precompileJSP\build.xml:45: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable builds[javac] Compiling 2 source files to E:\bench-cluster\spring_in_action_eclipse\precompileJSP\Webroot\WEB-INF\JspC\classesBUILD SUCCESSFULTotal time: 0 secondsE:\bench-cluster\spring_in_action_eclipse\precompileJSP>ant class2jarBuildfile: E:\bench-cluster\spring_in_action_eclipse\precompileJSP\build.xmlclass2jar:[jar] Building jar: E:\bench-cluster\spring_in_action_eclipse\precompileJSP\WebRoot\WEB-INF\lib\precompileJSPJSP.jarBUILD SUCCESSFULTotal time: 0 seconds
