原文地址：http://reason2003.iteye.com/blog/1627353
之前做一个项目，主程序打包成一个jar文件，因为用到了很多第三方的lib包，所以直接通过java命令运行jar比较烦琐，通过研究jar中的MANIFEST.MF文件，我们发现其中一个Class-Path属性，但这个属性值比较奇怪，不支持正则。所以要配置使用到的第三方包，必须明确相对路径和包名。如果手写MANIFEST.MF，工作量会比较大。幸好ant可以帮我们自动生成Class-Path属性。具体的请看下面的ant的执行脚本
第一步，定义一些属性
1 <!-- name of the output .jar file -->
2 <property name="jar.name" value="ourjarfile.jar" />
3 <!-- base directory for distribution target -->
4 <property name="dist.home" value="dist" />
5 <!-- base directory for compilation targets -->
6 <property name="build.home" value="target" />
7 <!-- The base directory for all libraries (jar) files -->
8 <property name="lib.home" value="lib" />
9
第二步，创建主程序的jar文件，这里会创建Class-Path的属性，并生成相应的MANIFEST.MF
1 <target name="jar" depends="compile" description="Create jar and MANIFEST.MF">
2
3
4
5 <!-- create a property containing all .jar files, prefix lib/, and seperated with a space -->
6
7 <pathconvert property="libs.project" pathsep=" ">
8
9 <mapper>
10
11 <chainedmapper>
12 <!-- remove absolute path -->
13 <flattenmapper />
14 <!-- add lib/ prefix -->
15 <globmapper from="*" to="lib/*" />
16 </chainedmapper>
17 </mapper>
18 <path>
19 <!-- lib.home contains all jar files, in several subdirectories -->
20 <fileset dir="${lib.home}">
21 <include name="**/*.jar" />
22 </fileset>
23 </path>
24 </pathconvert>
25 <!-- create the jar -->
26 <jar jarfile="${build.home}/${jar.name}" basedir="${build.home}/classes">
27 <!-- define MANIFEST.MF -->
28 <manifest>
29 <attribute name="Built-By" value="${user.name}" />
30 <attribute name="Main-Class" value="my.path.to.the.main.Application" />
31 <section name="common">
32 <attribute name="Specification-Title" value="${component.name}" />
33 <attribute name="Specification-Version" value="${component.version}" />
34 <attribute name="Specification-Vendor" value="${component.vendor}" />
35 <attribute name="Implementation-Title" value="${component.name}" />
36 <attribute name="Implementation-Version" value="${component.version} ${TODAY}" />
37 <attribute name="Implementation-Vendor" value="${component.vendor}" />
38 </section>
39 <!-- finally, use the magically generated libs path -->
40 <attribute name="Class-Path" value="${libs.project}" />
41 </manifest>
42 </jar>
43 </target>
44