关于Apache Maven您不知道的5件事-5个技巧
Maven 是为Java开发人员提供的一个极为优秀的构建工具，您也可以使用它来管理您的项目生命周期。作为一个生命周期管理工具，Maven是基于阶段操作的，而不像Ant是基于“任务”构建的。Maven 完成项目生命周期的所有阶段，包括验证、代码生成、编译、测试、打包、集成测试、安装、部署、以及项目网站创建和部署。
为了更好地理解Maven和传统构建工具的不同，我们来看看构建一个JAR文件和一个EAR文件的过程。使用Ant，您可能需要定义专有任务来组装每个工件。另一方面，Maven 可以为您完成大部分工作：您只需要告诉它是一个 JAR 文件还是一个 EAR 文件，然后指示它来完成 “打包” 过程。Maven 将会找到所需的资源，然后构建文件。
本文的5个技巧目的是帮助您解决即将出现的一些问题：使用Maven管理您的应用程序的生命周期时，将会出现的编程场景。
1. 可执行的JAR文件
使用 Maven 构建一个 JAR 文件比较容易：只要定义项目包装为 “jar”，然后执行包装生命周期阶段即可。但是定义一个可执行 JAR 文件却比较麻烦。采取以下步骤可以更高效：
在您定义可执行类的 JAR 的 MANIFEST.MF 文件中定义一个 main 类。(MANIFEST.MF 是包装您的应用程序时 Maven 生成的。)
找到您项目依赖的所有库。
在您的 MANIFEST.MF 文件中包含那些库，便于您的应用程序找到它们。
您可以手工进行这些操作，或者要想更高效，您可以使用两个 Maven 插件帮助您完成：maven-jar-plugin 和 maven-dependency-plugin。
maven-jar-plugin
maven-jar-plugin 可以做很多事情，但在这里，我们只对使用它来修改默认 MANIFEST.MF 文件的内容感兴趣。在您的 POM 文件的插件部分添加清单 1 所示代码：
清单 1. 使用 maven-jar-plugin 修改 MANIFEST.MF
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jar-plugin</artifactId> <configuration> <archive> <manifest> <addClasspath>true</addClasspath> <classpathPrefix>lib/</classpathPrefix> <mainClass>com.mypackage.MyClass</mainClass> </manifest> </archive> </configuration> </plugin>
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-dependency-plugin</artifactId> <executions> <execution> <id>copy</id> <phase>install</phase> <goals> <goal>copy-dependencies</goal> </goals> <configuration> <outputDirectory> $...{project.build.directory}/lib </outputDirectory> </configuration> </execution> </executions> </plugin><plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jar-plugin</artifactId> <configuration> <archive> <manifestFile> src/main/resources/META-INF/MANIFEST.MF </manifestFile> <manifest> <addClasspath>true</addClasspath> <classpathPrefix>lib/</classpathPrefix> <mainClass> </mainClass> </manifest> </archive> </configuration> </plugin>
<profiles> <profile> <id>deploywar</id> <build> <plugins> <plugin> <groupId>net.fpic</groupId> <artifactId>tomcat-deployer-plugin</artifactId> <version>1.0-SNAPSHOT</version> <executions> <execution> <id>pos</id> <phase>install</phase> <goals> <goal>deploy</goal> </goals> <configuration> <host>$...{deploymentManagerRestHost}</host> <port>$...{deploymentManagerRestPort}</port> <username>$...{deploymentManagerRestUsername}</username> <password>$...{deploymentManagerRestPassword}</password> <artifactSource> address/target/addressservice.war </artifactSource> </configuration> </execution> </executions> </plugin> </plugins> </build> </profile> </profiles><! Defines the development deployment information > <profile> <id>dev</id> <activation> <property> <name>env</name> <value>dev</value> </property> </activation> <properties> <deploymentManagerRestHost>10.50.50.52</deploymentManagerRestHost> <deploymentManagerRestPort>58090</deploymentManagerRestPort> <deploymentManagerRestUsername>myusername</deploymentManagerRestUsername> <deploymentManagerRestPassword>mypassword</deploymentManagerRestPassword> </properties> </profile> <! Defines the QA deployment information > <profile> <id>qa</id> <activation> <property> <name>env</name> <value>qa</value> </property> </activation> <properties> <deploymentManagerRestHost>10.50.50.50</deploymentManagerRestHost> <deploymentManagerRestPort>58090</deploymentManagerRestPort> <deploymentManagerRestUsername> myotherusername </deploymentManagerRestUsername> <deploymentManagerRestPassword> myotherpassword </deploymentManagerRestPassword> </properties> </profile>
package net.fpic.maven.plugins; import java.io.File; import java.util.StringTokenizer; import net.fpic.tomcatservice64.TomcatDeploymentServerClient; import org.apache.maven.plugin.AbstractMojo; import org.apache.maven.plugin.MojoExecutionException; import com.javasrc.server.embedded.CommandRequest; import com.javasrc.server.embedded.CommandResponse; import com.javasrc.server.embedded.credentials.Credentials; import com.javasrc.server.embedded.credentials.UsernamePasswordCredentials; import com.javasrc.util.FileUtils; /** *//** * Goal that deploys a web application to Tomcat * * @goal deploy * @phase install */ public class TomcatDeployerMojo extends AbstractMojo ...{ /** *//** * The host name or IP address of the deployment server * * @parameter alias="host" expression="${deploy.host}" @required */ private String serverHost; /** *//** * The port of the deployment server * * @parameter alias="port" expression="${deploy.port}" default-value="58020" */ private String serverPort; /** *//** * The username to connect to the deployment manager (if omitted then the plugin * attempts to deploy the application to the server without credentials) * * @parameter alias="username" expression="${deploy.username}" */ private String username; /** *//** * The password for the specified username * * @parameter alias="password" expression="${deploy.password}" */ private String password; /** *//** * The name of the source artifact to deploy, such as target/pos.war * * @parameter alias="artifactSource" expression=${deploy.artifactSource}" * @required */ private String artifactSource; /** *//** * The destination name of the artifact to deploy, such as ROOT.war. * If not present then the * artifact source name is used (without pathing information) * * @parameter alias="artifactDestination" * expression=${deploy.artifactDestination}" */ private String artifactDestination; public void execute() throws MojoExecutionException ...{ getLog().info( "Server Host: " + serverHost + ", Server Port: " + serverPort + ", Artifact Source: " + artifactSource + ", Artifact Destination: " + artifactDestination ); // Validate our fields ...{ throw new MojoExecutionException( "No deployment host specified, deployment is not possible" ); } ...{ throw new MojoExecutionException( "No source artifact is specified, deployment is not possible" ); } ... } }