Maven常用插件

maven利用各种插件来管理构建项目，本文记录下工作中常用到的插件及使用方法。每个插件都会提供多个目标(goal)，用于标示任务。各插件配置在pom.xml里，如下：

<build>
  [...]
  <plugins>
    <plugin>
      ...
    </plugin>
  </plugins>
  [...]
</build>

常用插件见：http://maven.apache.org/plugins/index.html，http://www.mojohaus.org/plugins.html。

maven-compiler-plugin

用于编译源代码，默认在compile阶段被调用。两个goal，compiler:compile/compiler:testCompile

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.3</version>
    <configuration>
        <!--源码的Java版本-->
        <source>1.7</source>
        <!--运行环境的Java版本-->
        <target>1.7</target>
    </configuration>
</plugin>

maven-surefire-plugin

test阶段执行单元测试，路径src/test/java

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-surefire-plugin</artifactId>
  <version>2.18.1</version>
  <configuration>
    <!--不执行的单元测试文件-->
    <excludes>
      <exclude>bvt/*.java</exclude>
    </excludes>
    <!--并行运行-->
    <parallel>methods</parallel>
    <threadCount>10</threadCount>
  </configuration>
</plugin>

appassembler-maven-plugin

生成启动Java应用的脚本，命令 mvn package appassembler:assemble

<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>appassembler-maven-plugin</artifactId>
<version>1.10</version>
<configuration>
  <!-- Set the target configuration directory to be used in the bin scripts，默认路径是etc -->
  <configurationDirectory>configuration</configurationDirectory>
  <!-- 源配置文件目录，默认目录是src/main/config -->
  <configurationSourceDirectory>src/main/resources</configurationSourceDirectory>
  <!--Copy the contents from configurationSourceDirectory to the target configuration directory-->
  <copyConfigurationDirectory>true</copyConfigurationDirectory>
  <!-- Include the target configurationDirectory in the beginning of the classpath declaration in the bin scripts -->
  <includeConfigurationDirectoryInClasspath>true</includeConfigurationDirectoryInClasspath>
  <!--assemble the artifacts in and place the bin scripts-->
  <assembleDirectory>release</assembleDirectory>
  <!--jar存放目录-->
  <repositoryName>lib</repositoryName>
  <!--lib下直接存放jar，没有路径文件夹（如com/apache)-->
  <repositoryLayout>flat</repositoryLayout>
  <programs>
    <program>
      <!--指定主类，脚本名。会生成shell/bat两种类型,也可用platforms指定运行平台-->
      <mainClass>com.mycompany.app.App</mainClass>
      <name>startapp</name>
    </program>
  </programs>
</configuration>
</plugin>

maven-assembly-plugin

对项目的源码、jar包、依赖、文档、目录等文件归档生成分发包，支持jar/war/zip/tar/tar.gz等归档格式。如写mapreduce job时可以使用生成一个jar包，包含所有的依赖，便于上传job。
命令mvn assembly:single，也可以绑定到package阶段，自动执行。下面的配置会生成如下文件：target/sample-1.0-SNAPSHOT-jar-with-dependencies.jar

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-assembly-plugin</artifactId>
  <version>2.4</version>
  <configuration>
    <descriptorRefs>
      <!--使用插件提供的配置，包含jar和依赖-->
      <descriptorRef>jar-with-dependencies</descriptorRef>
    </descriptorRefs>
    <!--也可以自定义打包内容，使用descriptor指定路径-->
    <!--descriptor>src/main/assembly/assembly.xml</descriptor-->
  </configuration>
  <executions>
    <execution>
      <id>make-assembly</id>
      <!--目标single绑定到package阶段，package阶段自动被调用-->
      <phase>package</phase>
      <goals>
        <goal>single</goal>
      </goals>
    </execution>
  </executions>
</plugin>