摘要：Maven，生命周期，插件
Maven的生命周期是抽象的，其实际都是由插件完成的，生命周期和插件两者密不可分
三套生命周期
Maven有三套生命周期，分别是clean，default，site，clean的目的是清理项目，default的目的是构建项目，site的目的是建立项目站点。每个生命周期包含一些阶段，后面的阶段依赖于前面的阶段，三套生命周期是互相独立的，调用某个生命周期的阶段不会对其他生命周期产生任何影响。
clean阶段
clean生命周期的目的是清理项目，包含三个阶段
（1）pre-clean：执行一些清理前需要完成的工作
（2）clean：清理上一次构建生成的文件
（3）post-clean：执行一些清理后需要完成的工作
default生命周期
default是核心，是构建项目时需要用到的生命周期，它包含主要以下几个阶段
（1）validate
（2）initialize
（3）process-sources：将项目主资源文件src/main/resources复制到项目输出的主classpath目录中
（4）compile：编译项目的主源码，编译src/main/java下的java文件到输出的主classpath中
（5）process-test-sources：处理项目测试资源文件。将src/test/resources下的内容复制到测试classpath中
（6）test-compile：编译代码的测试代码，编译src/test/java下的java文件到输出的测试classpath中
（7）test：使用单元测试进行代码测试，测试代码不会被打包或部署
（8）package：接受编译好的代码，输出成可发布的格式如jar
（9）install：将包安装到本地仓库，提供其他Maven项目使用
（10）deploy：将包复制到远程仓库
site生命周期
site生命周期的目的是建立和发布项目站点
（1）pre-site：执行一些在生成项目站点之前需要完成的工作
（2）site：生成项目站点文档
（3）post-site：执行一些在生成项目站点之后需要完成的工作
（4）site-deploy：将生成的项目站点发布到服务器上
命令行与生命周期
从命令行执行Maven命令的主要任务就是调用Maven的生命周期，比如
- mvn clean：调用clean生命周期的clean阶段，实际执行clean生命周期的pre-clean和clean阶段
- mvn clean install：该命令调用clean生命周期的clean阶段，和default生命周期的install阶段，实际执行的是clean生命周期的pre-clean和clean阶段和default周期的从validate到install的阶段
运行命令行插件如下，可以看到插件执行的顺序，每个插件冒号后面的内容是目标（goal），目标就是插件的其中的一个功能
root@ubuntu:~/myproject/InstallTest# mvn clean install
[INFO] Scanning for projects...
[INFO]
[INFO] -------------------< org.mycom.example:InstallTest >--------------------
[INFO] Building My First APP InstallTest 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ InstallTest ---
[INFO] Deleting /home/myproject/InstallTest/target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ InstallTest ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.2:compile (default-compile) @ InstallTest ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /home/myproject/InstallTest/target/classes
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ InstallTest ---
[WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory /home/myproject/InstallTest/src/test/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.2:testCompile (default-testCompile) @ InstallTest ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /home/myproject/InstallTest/target/test-classes
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ InstallTest ---
[INFO] Surefire report directory: /home/myproject/InstallTest/target/surefire-reports
-------------------------------------------------------
T E S T S
-------------------------------------------------------
Running MainTest
Tests run: 0, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec
Results :
Tests run: 0, Failures: 0, Errors: 0, Skipped: 0
[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ InstallTest ---
[INFO] Building jar: /home/myproject/InstallTest/target/InstallTest-1.0-SNAPSHOT.jar
[INFO]
[INFO] --- maven-shade-plugin:2.3:shade (default) @ InstallTest ---
[INFO] Replacing original artifact with shaded artifact.
[INFO] Replacing /home/myproject/InstallTest/target/InstallTest-1.0-SNAPSHOT.jar with /home/myproject/InstallTest/target/InstallTest-1.0-SNAPSHOT-shaded.jar
[INFO]
[INFO] --- maven-install-plugin:2.4:install (default-install) @ InstallTest ---
[INFO] Installing /home/myproject/InstallTest/target/InstallTest-1.0-SNAPSHOT.jar to /home/.m2/repository/org/mycom/example/InstallTest/1.0-SNAPSHOT/InstallTest-1.0-SNAPSHOT.jar
[INFO] Installing /home/myproject/InstallTest/pom.xml to /home/.m2/repository/org/mycom/example/InstallTest/1.0-SNAPSHOT/InstallTest-1.0-SNAPSHOT.pom
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.852 s
[INFO] Finished at: 2020-12-07T16:02:30+08:00
[INFO] ------------------------------------------------------------------------
一些常用的插件
maven-compiler-plugin对 Java 代码编译，maven-compiler-plugin 默认的 JDK 版本为 1.5需要修改configuration下的source和target
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.2</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
maven-scala-plugin对 Scala 代码编译，其中每个execution可以执行一个配置，id是随便起的也可以不指定，phase是需要绑定到的生命周期阶段，goal是需要绑定的插件
<plugin>
<groupId>org.scala-tools</groupId>
<artifactId>maven-scala-plugin</artifactId>
<executions>
<execution>
<id>scala-compile-first</id>
<phase>process-resources</phase>
<goals>
<goal>add-source</goal>
<goal>compile</goal>
</goals>
</execution>
<execution>
<id>scala-test-compile</id>
<phase>process-test-resources</phase>
<goals>
<goal>testCompile</goal>
</goals>
</execution>
</executions>
<configuration>
<scalaVersion>${scala.version}</scalaVersion>
<args>
<arg>-target:jvm-1.5</arg>
</args>
</configuration>
</plugin>
maven-shade-plugin将依赖的jar包打包到当前jar包，该插件只有一个目标shade，将他绑定到package阶段，该插件会生成2个jar包，original开头的只包含工程的class文件，另一个是可执行jar包，包含class文件和依赖
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<configuration>
<artifactSet>
<includes>
<include>*:*</include>
</includes>
</artifactSet>
</configuration>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<finalName>${project.artifactId}-${project.version}</finalName>
<filters>
<filter>
<artifact>*:*</artifact>
<excludes>
<exclude>META-INF/*.SF</exclude>
<exclude>META-INF/*.DSA</exclude>
<exclude>META-INF/*.RSA</exclude>
</excludes>
</filter>
</filters>
</configuration>
</execution>
</executions>
</plugin>
可以在maven-shade-plugin插件中指定main方法
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>2.3</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<filters>
<filter>
<artifact>*:*</artifact>
<excludes>
<exclude>META-INF/*.SF</exclude>
<exclude>META-INF/*.DSA</exclude>
<exclude>META-INF/*.RSA</exclude>
</excludes>
</filter>
</filters>
<transformers>
<transformer
implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<!--可以指定mian方法 -->
<mainClass>com.myproject.Main</mainClass>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
网友评论