喜欢Ant不喜欢Maven的有福了

1. Ant+Ivy VS. Maven

Maven是一个比Ant更强大的工具，除了构建项目它还可以管理项目的依赖，甚至可以一键生成项目网站；

但是，对于一般的企业应用，Maven太过复杂难用了：

• Maven脚本是配置式的风格，其构建过程已固化在工具内部不可改变，只能通过修改配置来改变Maven的构建行为，学习难度和使用难度都很高；
• Maven对项目工程结构有严格要求，对遗留系统不友好；

上述两点恰好是Ant的优势，同时Ant借助Ivy也可以获得跟Maven一样的依赖管理能力（其实Ivy依赖管理比Maven做的更好，配置也更简洁）。

2. Ivy的安装

下载Ivy的最新发布包（http://apache.dataguru.cn/ant/ivy/），解压后将其中的jar包（例如ivy-2.3.0.jar）copy到ant_home/lib下即可；

3. Ant集成Ivy

如果你的工程已经在用Ant构建，那么只需以下几部操作即可为工程添加Ivy依赖管理能力：

• 在工程根目录创建ivysettings.xml，如下：

xml version = "1.0" encoding = "ISO-8859-1" ?>
< ivysettings >
    < ivy:configure >
        < credentials host = "192.168.1.234" realm = "Sonatype Nexus Repository Manager" username = "deployment" passwd = "deployment123" />
    ivy:configure >
    < settings defaultResolver = "defaultChain" defaultConflictManager = "latest-revision" />
    < caches defaultCacheDir = "d:/.ivy2" />
    < property name = "nexus-public" value = "http://192.168.1.234:8081/nexus/content/groups/public" />
    < property name = "nexus-releases" value = "http://192.168.1.234:8081/nexus/content/repositories/releases" />
    < property name = "nexus-snapshots" value = "http://192.168.1.234:8081/nexus/content/repositories/snapshots" />
    < resolvers >
        < chain name = "defaultChain" checkmodified = "true" changingPattern = ".*SNAPSHOT" >

            < ibiblio name = "public" m2compatible = "true" usepoms = "true" />


        chain >
    resolvers >
ivysettings >

• 在工程根目录创建ivy.xml，如下：

< ivy-module version = "1.0" >
    < info organisation = "com.abc" module = "project17" />
    < configurations >
        < conf name = "default" visibility = "public" extends = "runtime,master" />
        < conf name = "master" visibility = "public" />
        < conf name = "compile" visibility = "public" />
        < conf name = "provided" visibility = "public" />
        < conf name = "runtime" visibility = "public" extends = "compile" />
        < conf name = "test" visibility = "private" extends = "runtime" />
    configurations >
    < dependencies defaultconfmapping="compile->compile(*),master(*);runtime->master(*),compile(*),runtime(*)">

        < dependency org = "org.slf4j" name = "slf4j-api" rev = "1.7.3" conf = "compile;runtime" />
        < dependency org = "org.slf4j" name = "slf4j-log4j12" rev = "1.7.3" conf = "compile;runtime" />

        < dependency org = "javax.servlet" name = "servlet-api" rev = "2.5" conf="provided->default" />

        < dependency org = "junit" name = "junit" rev = "4.8.2" conf="test->default" />
    dependencies >
ivy-module >

• 修改工程的build.xml，如下：

< property name = "publish.version" value = "0.01" />
< property name = "ivy.report.todir" value = "build" />

< ivy:settings file = "ivysettings.xml" />

< target name = "resolve" description = "-- parse ivy.xml" >
    < ivy:resolve file = "ivy.xml" conf = "*" useCacheOnly = "true" />
    < ivy:cachepath pathid = "ivy.libs.compile" type = "jar,bundle" conf = "compile,provided" />
    < ivy:cachepath pathid = "ivy.libs.test" type = "jar,bundle" conf = "test,provided" />
    < ivy:cachepath pathid = "ivy.libs.runtime" type = "jar,bundle" conf = "runtime" />
target >

< target name = "compile" depends = "resolve" >
        < mkdir dir = "${classes.dir}" />
        < javac target = "1.6" encoding = "utf-8" srcdir = "src" destdir = "${classes.dir}" debug = "${build.debug}" includeantruntime = "false" >
            < compilerarg value = "-Xlint:unchecked" />
            < classpath >
                < path refid = "ivy.libs.compile" />
                < path refid = "ivy.libs.test" />
            classpath >
        javac >
target >

< target name = "report" depends = "resolve" description="--> resolve and retrieve dependencies with ivy">
        < ivy:report />
target >

OK！至此，你已经为蚂蚁插上了Ivy的翅膀，原来直接堆在工程lib目录下的杂乱的jar可以删掉了，

执行ant resolve target，Ivy会按照ivy.xml中声明的dependency自动为你下载所需的所有jar包，

你会发现下载的jar比你声明的dependency个数要多，那是因为ivy会自动下载间接依赖的jar；

下载的jar会被整齐有序的存放在d:/.ivy2，并且可以被多个项目复用；

4. Eclipse集成Ivy

Ant集成Ivy只是解决了在命令行工具中进行工程打包时的依赖管理问题，

而实际工作中开发人员主要在Eclipse中进行编译、调试以及调用Ant构建工程，也需要解决依赖包管理问题；

好在Ivy提供的Eclipse插件来解决这个问题，安装配置如下：

• Window－＞preference－＞ant－＞RunTime－＞Classpath－＞Ant Home Entries，右边Add External Jars，添加ivy-2.3.0.jar，这样就完成了Eclipse中的Ant与Ivy集成；
• 安装Ivy插件:Help－＞Install new software－＞add，Name: IvyDE，Location: http://www.apache.org/dist/ant/ivyde/updatesite ；安装成功后重启eclipse；
• 重启eclipse后，Window－＞preference－＞ivy－＞settings；Ivy settings path设为${ivyproject_loc}/ivysettings.xml (eclipse3.7 Indigo)

至此Eclipse的ivy插件配置好了，然后就可以为你的项目classpath添加ivy依赖了：

• 选中项目->右键 属性－＞Java Build Path－＞Libraries->Add Library...->IvyIDE Managed Dependencies->finish->OK
• 然后神奇的事情就出现了——虽然你工程目录下一个jar包也有，只是在ivy.xml里面声明了一下，你的项目就可以编译通过了，如下图：