build-helper-maven-plugin的使用

build-helper-maven-plugin 插件主要的作用就是用来指定额外的源码路径和资源路径。它总共有15个goal：

• build-helper:add-source Add more source directories to the POM.
• build-helper:add-test-source Add test source directories to the POM.
• build-helper:add-resource Add more resource directories to the POM.
• build-helper:add-test-resource Add test resource directories to the POM.
• build-helper:attach-artifact Attach additional artifacts to be installed and deployed.
• build-helper:maven-version Set a property containing the current version of maven.
• build-helper:parse-version Set properties containing the parsed components of a version string.
• build-helper:regex-property Sets a property by applying a regex replacement rule to a supplied value.
• build-helper:regex-properties Sets a property by applying a regex replacement rule to a supplied value.
• build-helper:released-version Resolve the latest released version of this project.
• build-helper:remove-project-artifact Remove project's artifacts from local repository.
• build-helper:reserve-network-port Reserve a list of random and unused network ports.
• build-helper:local-ip Retrieve current host IP address.
• build-helper:cpu-count Retrieve number of available CPU.
• build-helper:timestamp-property Sets a property based on the current date and time.

这里重点介绍一下attach-artifact这个goal，它的作用就是在安装或部署artifact的时候，附加的安装或部署一些其他资源或文件。

 

要使用 build-helper-maven-plugin，首先添加插件声明：

  <build>
  	<plugins>
  		<plugin>
  			<groupId>org.codehaus.mojo</groupId>
  			<artifactId>build-helper-maven-plugin</artifactId>
  			<version>1.9</version>
  		</plugin>
  	</plugins>
  </build>

然后和其他插件一样，定义它的phase和goal。

 

attach-artifact默认的phase是package：

	<build>
		<plugins>
			<plugin>
				<groupId>org.codehaus.mojo</groupId>
				<artifactId>build-helper-maven-plugin</artifactId>
				<version>1.8</version>
				<executions>
					<execution>
						<phase>package</phase>
						<goals>
							<goal>attach-artifact</goal>
						</goals>
					</execution>
				</executions>
			</plugin>
		</plugins>
	</build>

剩下的就是configuratino配置了。

 

attach-artifact可用的配置如下：

必选

Name Type Since Description

artifacts	Artifact[]	1.0	Attach an array of artifacts to the project.

可选

Name Type Since Description

basedir	String	1.5	This project's base directory. Default value is: ${basedir}.
runOnlyAtExecutionRoot	boolean	1.5	This will cause the execution to be run only at the top of a given module tree. That is, run in the project contained in the same folder where the mvn execution was launched. Default value is: false. User property is: buildhelper.runOnlyAtExecutionRoot.
skipAttach	boolean	1.6	This allows to skip the attach execution in case it is known that the corresponding file does not exists. For exemple, when the previous ant-run task is skipped with a unless. Default value is: false. User property is: buildhelper.skipAttach.

这里只有artifacts是必选的；artifacts的说明如下：

artifacts:

Attach an array of artifacts to the project.

• Type: org.codehaus.mojo.buildhelper.Artifact[]
• Since: 1.0
• Required: Yes

其中的每个artifact是类型org.codehaus.mojo.buildhelper.Artifact。根据Artifact Doc说明，它只有三个可配置项：

• file：指定欲附加的文件
• type：指定文件类型
• classifier：指定文件的附属信息

最后生成的文件名会是：

${artifactId}-${version}-${classifier}.${type}

例如，想在安装或部署的时候附加 etc/a.properties 文件，则配置如下：

				<configuration>
					<artifacts>
						<artifact>
							<file>etc/a.properties</file>
							<type>properties</type>
							<classifier>org.liugang.settings</classifier>
						</artifact>
					</artifacts>
				</configuration>

假设当前pom的groupId/artifactId/version为： org.liugang.maven.resources/BuilderHelperTester/0.0.1-SNAPSHOT

 

则运行完 mvn clean install 之后，到本地Maven库的目录：

${M2Repository}\org\liugang\maven\resources\BuilderHelperTester\0.0.1-SNAPSHOT

下就可以看到除了生成对应的jar文件，还会生成一个文件：

BuilderHelperTester-0.0.1-SNAPSHOT-org.liugang.settings.properties

这个文件的内容即 etc/a.properties 里的内容。

然后如果要引用这个properties文件，需要指定具体的type和classifier，例如：

 

			<groupId>org.liugang.maven.resources</groupId>
			<artifactId>BuilderHelperTester</artifactId>
			<version>0.0.1-SNAPSHOT</version>
		 	<type>properties</type> 
		 	<classifier>org.liugang.settings</classifier> 

像在karaf里就可以通过这种方式读取一些bundle的额外设置：

<configfile finalname="/etc/org.liugang.settings.cfg">mvn:org.liugang.maven.resources/BuilderHelperTester/0.0.1-SNAPSHOT/properties/org.liugang.settings</configfile> 

其中路径的格式为：

mvn:${groupId}/${artifactId}/${version}/${type}/${classifier}