自定义maven插件 Hello, mojo.

• 参考文档：https://maven.apache.org/guides/plugin/guide-java-plugin-development.html

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>cn.go</groupId>
    <artifactId>plugin_demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>maven-plugin</packaging>


    <dependencies>
        <dependency>
            <groupId>org.apache.maven</groupId>
            <artifactId>maven-plugin-api</artifactId>
            <version>3.0</version>
        </dependency>

        <!-- dependencies to annotations -->
        <dependency>
            <groupId>org.apache.maven.plugin-tools</groupId>
            <artifactId>maven-plugin-annotations</artifactId>
            <version>3.4</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>


</project>

GreetingMojo.java

package cn.go;

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

@Mojo(name = "go")
public class GreetingMojo extends AbstractMojo {
    public void execute() throws MojoExecutionException {
        getLog().info("Hello, mojo.");
    }
}

运行 install

install 报错

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-plugin-plugin:3.2:descriptor (default-descriptor) on project plugin_demo: Execution default-descriptor of goal org.apache.maven.plugins:maven-plugin-plugin:3.2:descriptor failed: Plugin org.apache.maven.plugins:maven-plugin-plugin:3.2 or one of its dependencies could not be resolved: The following artifacts could not be resolved: org.apache.maven.plugin-tools:maven-plugin-tools-annotations:jar:3.2, org.apache.maven.plugin-tools:maven-plugin-tools-api:jar:3.2, org.apache.maven.plugin-tools:maven-plugin-tools-generators:jar:3.2, org.apache.maven.plugin-tools:maven-plugin-tools-java:jar:3.2, org.apache.maven.plugin-tools:maven-plugin-tools-beanshell:jar:3.2, org.apache.maven.plugin-tools:maven-plugin-tools-model:jar:3.2: Failure to find org.apache.maven.plugin-tools:maven-plugin-tools-annotations:jar:3.2 in http://10.129.2.106:8081/nexus/content/groups/public/ was cached in the local repository, resolution will not be reattempted until the update interval of nexus-private has elapsed or updates are forced -> [Help 1]

• 错误原因是 ，构建时缺失依赖

• 上图是一个构建的标准生命周期，报错的阶段是图中圈出的节点；
• 解决方法（2个方法任意一个都行，不是两个步骤）：
  • 1、手动下载对应依赖，可参考我的这篇博客：https://blog.csdn.net/wwq921220/article/details/106918751
  • 2、禁用 settings.xml 文件中的私服配置，使maven连接到默认的中心仓库；如果连接不上可配置代理（前提是可以连接公网）

配置代理

<proxies>
    <!-- proxy
     | Specification for one proxy, to be used in connecting to the network.
     |
    <proxy>
      <id>optional</id>
      <active>true</active>
      <protocol>http</protocol>
      <username>proxyuser</username>
      <password>proxypass</password>
      <host>proxy.host.net</host>
      <port>80</port>
      <nonProxyHosts>local.net|some.host.com</nonProxyHosts>
    </proxy>
    -->
	
	
	 <!-- <proxy> -->
        <!-- id 代理的名称（随便设） -->
        <!-- <id>optional</id> -->
        <!-- true 表示生效 -->
        <!-- <active>true</active> -->
        <!-- 协议 -->
        <!-- <protocol>http</protocol> -->
        <!-- 本机上网用户名及密码，如果没有，请注释或者是删除 -->
        <!-- <username>*******.ex</username> -->
        <!-- <password>a*169646</password> -->
        <!-- 公司上网使用ip及端口，即代理，这里替换成相对应的ip和端口 -->
        <!-- <host>127.0.0.1</host> -->
        <!-- <port>8888</port> -->
        <!-- 填写不用代理的地址，以竖线|分割多个地址，一般填写本地Maven仓库地址 -->
        <!-- <nonProxyHosts>local.net</nonProxyHosts> -->
    <!-- </proxy> -->
	
	 <proxy>
        <id>optional</id>
        <active>true</active>
        <protocol>http</protocol>
        <host>127.0.0.1</host>
        <port>8888</port>
        <nonProxyHosts>local.net</nonProxyHosts>
    </proxy>
  </proxies>

pom.xml 中添加配置

<build>
        <plugins>
            <plugin>
                <groupId>cn.go</groupId>
                <artifactId>plugin_demo</artifactId>
                <version>1.0-SNAPSHOT</version>
            </plugin>
        </plugins>
    </build>

• 刷新项目，可以看到如下效果：

• 运行 goal mvn cn.go:plugin_demo:1.0-SNAPSHOT:go ；效果如图：