maven plugin 简单介绍和实战 (2021-05-29)

Posted master-dragon

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了maven plugin 简单介绍和实战 (2021-05-29)相关的知识，希望对你有一定的参考价值。

目录

maven plugin 开发： https://maven.apache.org/plugin-developers/index.html

什么是plugin?

“Maven” is really just a core framework for a collection of Maven Plugins. In other words, plugins are where much of the real action is performed, plugins are used to: create jar files, create war files, compile code, unit test code, create project documentation, and on and on. Almost any action that you can think of performing on a project is implemented as a Maven plugin.

  • plugin的作用

    1. create jar files (创建jar)
    2. create war files(创建war)
    3. compile code (编译源代码)
    4. unit test code (单元测试)
    5. create project documentation (创建项目文档)
    6. on and on（等等…）

什么是Mojo？

A Mojo is really just a goal in Maven, and plug-ins consist of any number of goals (Mojos). Mojos can be defined as annotated Java classes or Beanshell script. A Mojo specifies metadata about a goal: a goal name, which phase of the lifecycle it fits into, and the parameters it is expecting.

MOJO is a play on POJO (Plain-old-Java-object), substituting “Maven” for “Plain”. Mojo is also an interesting word (see definition). From Wikipedia, a “mojo” is defined as: “…a small bag worn by a person under the clothes (also known as a mojo hand). Such bags were thought to have supernatural powers, such as protecting from evil, bringing good luck, etc.”

mojo理解为一个执行目标，maven本身就是很多mojo组成的。mojo实现plugin，让用户自已在compile，process-classed,test,package,install, deploy等阶段实现特定的执行逻辑

maven plugin 的几个标准阶段

阶段含义
compileCompiles the Java code for the plugin
process-classesExtracts data to build the plugin descriptor
testRuns the plugin’s unit tests
packageBuilds the plugin jar
installInstalls the plugin jar in the local repository
deployDeploys the plugin jar to the remote repository

@Mojo的使用参考：https://maven.apache.org/developers/mojo-api-specification.html#The_Descriptor_and_Annotations

简单的定义plugin和使用plugin

如下就能简单的定义一个plugin的逻辑

package sample.plugin;
 
import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugins.annotations.Mojo;
 
/**
 * Says "Hi" to the user.
 *
 */
@Mojo( name = "sayhi")
public class GreetingMojo extends AbstractMojo
{
    public void execute() throws MojoExecutionException
    {
        getLog().info( "Hello, world." );
    }
}

plugin的pom依赖

<dependencies>
  <!-- https://mvnrepository.com/artifact/org.apache.maven/maven-plugin-api -->
    <dependency>
        <groupId>org.apache.maven</groupId>
        <artifactId>maven-plugin-api</artifactId>
        <version>3.8.1</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.apache.maven.plugin-tools/maven-plugin-annotations -->
    <dependency>
        <groupId>org.apache.maven.plugin-tools</groupId>
        <artifactId>maven-plugin-annotations</artifactId>
        <version>3.6.1</version>
        <scope>provided</scope>
    </dependency>
</dependencies>

在另一个工程模块中的pom.xml引入，然后就能使用该plugin了

 <build>
      <plugins>
           <plugin>
               <groupId>org.example</groupId>
               <artifactId>hello-maven-plugin</artifactId>
               <version>1.0-SNAPSHOT</version>
           </plugin>
       </plugins>
   </build>

参考：https://maven.apache.org/guides/plugin/guide-java-report-plugin-development.html

plugin重要功能之parameter

  • 可以自定义一些丰富的parameter：比如做生成jar和后续解析jar的操作，来适应丰富的变化。

关于参数的使用介绍：https://maven.apache.org/guides/plugin/guide-java-plugin-development.html#parameters

It is unlikely that a mojo will be very useful without parameters. Parameters provide a few very important functions:

  1. It provides hooks to allow the user to adjust the operation of the plugin to suit their needs.
  2. It provides a means to easily extract the value of elements from the POM without the need to navigate the objects.

使用例子：

/**
   * The greeting to display.
    */
   @Parameter( property = "sayhi.greeting", defaultValue = "Hello World!" )
   private String greeting;

<plugin>
  <groupId>sample.plugin</groupId>
  <artifactId>hello-maven-plugin</artifactId>
  <version>1.0-SNAPSHOT</version>
  <configuration>
  	<!--定义greeting参数的值-->
    <greeting>Welcome</greeting>
  </configuration>
</plugin>

需要说明的是，可以在plugin中使用getLog() 来打印 log 已方便调试或观察plugin执行阶段情况

parameter的类型是丰富的，eg:

boolean、Numbers、Dates、Files and Directories、URLs、Plain Text、Enums,Types With Multiple Values、
Other Object Classes

即我们可以自己定义参数类型来极大的方便了我们在构建jar的灵活性

指定plugin执行的阶段

例如指定默认deploy阶段完成某个Mojo：

@Mojo(name = "deploy", defaultPhase = LifecyclePhase.DEPLOY,
    requiresDependencyResolution = ResolutionScope.RUNTIME)
public class DeployMojo extends AbstractMojo {
	//...
}

参考：https://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html

实际例子编写

plugin 编写

package org.example;

import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugins.annotations.Mojo;

/**
 * Says "Hi" to the user.
 *
 */
@Mojo( name = "sayhi")
public class GreetingMojo extends AbstractMojo
{
    public void execute() throws MojoExecutionException
    {
        getLog().info( "plugin greeting" );
    }
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>hello-maven-plugin</artifactId>
    <version>1.0-SNAPSHOT</version>

    <packaging>maven-plugin</packaging>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.apache.maven/maven-plugin-api -->
        <dependency>
            <groupId>org.apache.maven</groupId>
            <artifactId>maven-plugin-api</artifactId>
            <version>3.8.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.apache.maven.plugin-tools/maven-plugin-annotations -->
        <dependency>
            <groupId>org.apache.maven.plugin-tools</groupId>
            <artifactId>maven-plugin-annotations</artifactId>
            <version>3.6.1</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>

    </dependencies>

</project>

然后mvn clean install -Dmaven.test.skip=true安装到本地

plugin使用

工程的pom.xml引入上述plugin

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>mvn-hello</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.apache.maven/maven-plugin-api -->
        <dependency>
            <groupId>org.apache.maven</groupId>
            <artifactId>maven-plugin-api</artifactId>
            <version>3.8.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.apache.maven.plugin-tools/maven-plugin-annotations -->
        <dependency>
            <groupId>org.apache.maven.plugin-tools</groupId>
            <artifactId>maven-plugin-annotations</artifactId>
            <version>3.6.1</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.example</groupId>
                <artifactId>hello-maven-plugin</artifactId>
                <version>1.0-SNAPSHOT</version>
                <executions>
                    <execution>
                        <phase>clean</phase>
                        <goals>
                            <goal>sayhi</goal>
                        </goals>
                        <configuration>
                            <tasks>
                                <echo>clean phase</echo>
                            </tasks>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>


</project>

通过mvn clean -Dmaven.test.skip=true就能在clean阶段执行

以上是关于maven plugin 简单介绍和实战 (2021-05-29)的主要内容，如果未能解决你的问题，请参考以下文章

Maven实战（七，八）——经常使用Maven插件介绍

Jboot使用appassembler-maven-plugin插件生成启动脚本

Maven实战之初识MavenMaven的简单介绍

Maven实战技巧「插件使用专题」Maven-Archetype插件创建自定义maven项目骨架

Maven实战与原理分析：Maven插件运行原理 + 常见插件汇总

#私藏项目实操分享#Maven实战技巧「插件使用专题」Maven-Archetype插件创建自定义maven项目骨架