Maven 简明教程

Maven - Plugins

What are Maven Plugins?

Maven 实际上是一个插件执行框架，其中的每一项任务都是由插件执行。Maven 插件通常用于：-

Maven is actually a plugin execution framework where every task is actually done by plugins. Maven Plugins are generally used to −

  1. create jar file

  2. create war file

  3. compile code files

  4. unit testing of code

  5. create project documentation

  6. create project reports

一个插件通常提供一组目标，这些目标可以使用以下语法执行：-

A plugin generally provides a set of goals, which can be executed using the following syntax −

mvn [plugin-name]:[goal-name]

例如，可以通过运行以下命令，使用 maven-compiler-plugin 的 compile-goal 编译一个 Java 项目。

For example, a Java project can be compiled with the maven-compiler-plugin’s compile-goal by running the following command.

mvn compiler:compile

Plugin Types

Maven 提供了以下两种类型的插件：-

Maven provided the following two types of Plugins −

Sr.No.

Type & Description

1

Build plugins They execute during the build process and should be configured in the <build/> element of pom.xml.

2

Reporting plugins They execute during the site generation process and they should be configured in the <reporting/> element of the pom.xml.

以下是几个常见插件的列表：-

Following is the list of few common plugins −

Sr.No.

Plugin & Description

1

clean Cleans up target after the build. Deletes the target directory.

2

compiler Compiles Java source files.

3

surefire Runs the JUnit unit tests. Creates test reports.

4

jar Builds a JAR file from the current project.

5

war Builds a WAR file from the current project.

6

javadoc Generates Javadoc for the project.

7

antrun Runs a set of ant tasks from any phase mentioned of the build.

Example

我们在示例中大量使用 maven-antrun-plugin 在控制台上打印数据。参考构建配置文件章节。让我们进一步了解一下它，并在 C:\MVN\project 文件夹中创建一个 pom.xml。

We’ve used maven-antrun-plugin extensively in our examples to print data on console. Refer Build Profiles chapter. Let us understand it in a better way and create a pom.xml in C:\MVN\project folder.

<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>com.companyname.projectgroup</groupId>
   <artifactId>project</artifactId>
   <version>1.0</version>
   <build>
      <plugins>
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-antrun-plugin</artifactId>
            <version>1.1</version>
            <executions>
               <execution>
                  <id>id.clean</id>
                  <phase>clean</phase>
                  <goals>
                     <goal>run</goal>
                  </goals>
                  <configuration>
                     <tasks>
                        <echo>clean phase</echo>
                     </tasks>
                  </configuration>
               </execution>
            </executions>
         </plugin>
      </plugins>
   </build>
</project>

接下来，打开命令控制台并转到包含 pom.xml 的文件夹，然后执行以下 mvn 命令。

Next, open the command console and go to the folder containing pom.xml and execute the following mvn command.

C:\MVN\project>mvn clean

Maven 将开始处理并显示 clean 生命周期中的 clean phase。

Maven will start processing and displaying the clean phase of clean life cycle.

C:\MVN>mvn clean
[INFO] Scanning for projects...
[INFO]
[INFO] ----------------< com.companyname.projectgroup:project >----------------
[INFO] Building project 1.0
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ project ---
[INFO] Deleting C:\MVN\target
[INFO]
[INFO] --- maven-antrun-plugin:1.1:run (id.clean) @ project ---
[INFO] Executing tasks
     [echo] clean phase
[INFO] Executed tasks
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  1.266 s
[INFO] Finished at: 2021-12-13T13:58:10+05:30
[INFO] ------------------------------------------------------------------------

C:\MVN>

上述示例说明了以下几个关键概念：-

The above example illustrates the following key concepts −

  1. Plugins are specified in pom.xml using plugins element.

  2. Each plugin can have multiple goals.

  3. You can define phase from where plugin should starts its processing using its phase element. We’ve used clean phase.

  4. You can configure tasks to be executed by binding them to goals of plugin. We’ve bound echo task with run goal of maven-antrun-plugin.

  5. Maven will then download the plugin if not available in local repository and start its processing.