maven基础及高级

## maven

## alias 配置别名

```bash
echo "alias mcp='mvn clean package'" >> ~/.bashrc
echo "alias mci='mvn clean install'" >> ~/.bashrc
source ~/.bashrc
```

#### 阿里云maven [settings.xml]

```xml
<mirror>
    <id>nexus-aliyun</id>
    <mirrorOf>*</mirrorOf>
    <name>Nexus aliyun</name>
    <url>http://maven.aliyun.com/nexus/content/groups/public</url>
</mirror>
```

#### 阿里云maven [pom.xml]

```xml
<repository>
    <id>maven-aliyun</id>
    <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
    <releases>
        <enabled>true</enabled>
    </releases>
    <snapshots>
        <enabled>true</enabled>
        <updatePolicy>always</updatePolicy>
        <checksumPolicy>fail</checksumPolicy>
    </snapshots>
</repository>
```

#### mirror 与 repository

- repository是仓库，说明要直连这个仓库获取jar。可被配置在pom.xml中
- mirror是镜像，会拦截对远程仓库的请求到配置的地址上

#### 反应堆

- https://juvenshun.iteye.com/blog/565240
- https://www.jianshu.com/p/29bb16755883
- http://maven.apache.org/guides/mini/guide-multiple-modules.html
- 说明 -pl (project list)，为要操作的模块，建议使用`groupId:artifactId`，以英文逗号分隔，-am(also make)参数把要操作的模块的依赖模块也进行处理
- 不建议在-pl的参数中使用pom的g:a而要使用它的子模块的g:a

`mvn clean package -pl groupId1:artifactId1,groupId2:artifactId2 -am`

####  一些命令

- 运行java类  `mvn exec:java -Dexec.mainClass=com.examples.Main`
- 显示依赖树  `mvn -X compile dependency:tree -Dverbose >a.log`
- 下载源代码jar  -DdownloadSources=true
- 下载javadoc包  -DdownloadJavadocs=true
- 跳过测试       -Dmaven.test.skip=true 或 -DskipTests
- 有时为了跳过测试，会使用参数-DskipTests和-Dmaven.test.skip=true，这两个参数的主要区别是：
  * -DskipTests，不执行测试用例，但编译测试用例类生成相应的class文件至target/test-classes下。
  * -Dmaven.test.skip=true，不执行测试用例，也不编译测试用例类。
- 确认未使用的依赖项 `mvn dependency:analyze`

#### 常用插件

```xml
    
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>2.3.2</version>
        <configuration>
            <source>1.7</source>
            <target>1.7</target>
            <encoding>utf8</encoding>
        </configuration>
    </plugin>

<plugin>
        <artifactId>maven-source-plugin</artifactId>
        <version>2.1</version>
        <configuration>
            <attach>true</attach>
        </configuration>
        <executions>
            <execution>
                <phase>compile</phase>
                <goals>
                    <goal>jar</goal>
                </goals>
            </execution>
        </executions>
    </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>lib</outputDirectory>
                </configuration>
            </execution>
        </executions>
    </plugin>

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>2.18.1</version>
        <configuration>
          <skipTests>true</skipTests>
        </configuration>
     </plugin>

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <version>2.4</version>
        <configuration>
            <archive>
                <manifest>
                    <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
                </manifest>
            </archive>
        </configuration>
    </plugin>

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <version>3.0.2</version>
        <configuration>
            <excludes>
                <exclude>com/project/MainApp*</exclude>
            </excludes>
        </configuration>
    </plugin>

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-antrun-plugin</artifactId>
        <version>1.1</version>
        <executions>
            <execution>
                <phase>validate</phase>
                <goals>
                    <goal>run</goal>
                </goals>
                <configuration>
                    <tasks>
                        <echo>
                        settings.localRepository = ${settings.localRepository}
                        </echo>
                        <echo>
                        project.build.directory = ${project.build.directory}
                        </echo>
                    </tasks>
                </configuration>
            </execution>
        </executions>
    </plugin>

<plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-deploy-plugin</artifactId>
        <version>2.8.2</version>
        <configuration>
            <skip>true</skip>
        </configuration>
    </plugin>
```

versions-maven-plugin
    https://maven.apache.org/maven-release/maven-release-plugin/index.html
    maven-release-plugin

#### pom.xml中使用属性

maven定义了很多变量属性,参考[这里](http://docs.codehaus.org/display/MAVENUSER/MavenPropertiesGuide)。

- 内置属性

```
${basedir} represents the directory containing pom.xml
${version} equivalent to ${project.version} or ${pom.version}
```

- Pom/Project properties

```
所有pom中的元素都可以用 'project.' 前缀进行引用，如${project.build.directory}，${project.build.finalName}
```

- 本地用户设定

```
所有用的的 settings.xml 中的设定都可以通过 'settings.' 前缀进行引用，如${settings.localRepository} refers to the path of the user's local repository.
```

- 环境变量

```
系统的环境变量通过 'env.' 前缀引用，如${env.M2_HOME}
```

- java系统属性

```
直接使用如${java.home}, ${java.version}, ${os.name}, ${file.separator}, ${path.separator}, ${line.separator}
```

- 用户在pom中定义的自定义属性（直接使用，此最常见）

```
<properties>
    <java.version>1.8</java.version>
</properties>
```

- 上级工程的变量

```
上级工程的pom中的变量用前缀 ${'project.parent.'} 引用.
```

#### 多环境配置

- 方法一 使用配置文件

```
常见的就是配置一个src/main/filters目录，里面有filter-dev.properties\filter-test.properties\filter-prod.properties等配置文件，每个文件里的key是相同的，只有Value不同
```

- 方法二 使用配置目录

这种方式也常见，配置多个类似的目录，在打包时指定使用哪一个，如下配置片段

```
        <resources>
            <resource>
                <directory>src/main/conf/${profiles.active}</directory>
            </resource>
        </resources>

<profiles>
           
           
           <profile>
               
               <id>development</id>
               <properties>
                   <profiles.active>dev</profiles.active>
               </properties>
               <activation>
                   <activeByDefault>true</activeByDefault>
               </activation>
           </profile>
           <profile>
               
               <id>production</id>
               <properties>
                   <profiles.active>production</profiles.active>
               </properties>
           </profile>
        </profiles>
```

#### 本地仓库无用文件清理

1. 使用cmd删除所有以.lastUpdate结尾的文件

切换到maven的本地仓库,在当前目录打开cmd命令行, 执行命令
`for /r %i in (*.lastUpdated) do del "%i"`

2. 清理空文件夹 for /f "delims=" %a in ('dir /ad /b /s E:\maven-repo\^|sort /r') do ( rd "%a">nul 2>nul && echo 空目录"%a"成功删除！)

#### 插件开发

#### using archetype

`mvn archetype:generate -DgroupId=com.billy.bigdata -DartifactId=bigdata-hadoop -DpackageName=com.billy.bigdata.hadoop -DarchetypeArtifactId=maven-archetype-quickstart -Dversion=1.0-SNAPSHOT -DinteractiveMode=false`

#### maven wrapper

使用 `mvn wrapper:wrapper`可以生成.mvn/wrapper/maven-wrapper.properties文件，大致内容如下（使用国内源）：

```text
#distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.0/apache-maven-3.6.0-bin.zip
distributionUrl=https://mirrors.huaweicloud.com/apache/maven/maven-3/3.6.3/binaries/apache-maven-3.6.3-bin.zip
#distributionUrl=http://mirrors.tuna.tsinghua.edu.cn/apache/maven/maven-3/3.6.3/binaries/apache-maven-3.6.3-bin.zip
#wrapperUrl=https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.1.1/maven-wrapper-3.1.1.jar
wrapperUrl=https://mirrors.huaweicloud.com/repository/maven/org/apache/maven/wrapper/maven-wrapper/3.1.1/maven-wrapper-3.1.1.jar
```

```bash
# maven wrapper可以使用如下（并未测试，因为使用的是settings.xml）
export MVNW_REPOURL=https://maven.aliyun.com/nexus/content/groups/public
# 指定.m2目录，默认是~/.m2
export MAVEN_USER_HOME=~/.m2_another_dir
```

## 并发编译/打包

`mvn clean package -DskipTests -T4`

### 私服

- nexus3
- reposilite

#### reposilite

<https://reposilite.com/>

##### what?

Lightweight repository manager for Maven artifacts.

##### why?

- Reduce usage of your resources to even 8MB of RAM
- 95%+ test coverage
- Easy to use

##### disadvantage against nexus3

- only support java, not support npm/docker

##### have a try

##### install

- download a jar named 'reposilite-VERSION.jar' from <https://github.com/dzikoysk/reposilite/releases>
- run `java -jar reposilite-VERSION.jar`
- visit <http://localhost:80/>

##### upload artifact

- generate token `keygen / user0 m`
- add alias and token into ~/.m2/settings.xml or $M2_HOME/conf/settings.xml
```xml
<server>
  <id>local-repo-release</id>
  <username>user0</username>
  <password>paste_token_here</password>
</server>
<server>
  <id>local-repo-snapshot</id>
  <username>user0</username>
  <password>paste_token_here</password>
</server>
```

- add below into pom.xml

```xml
<distributionManagement>
    <repository>
        <id>local-repo-release</id>
        <url>http://localhost:80/releases</url>
    </repository>
    <snapshotRepository>
        <id>local-repo-snapshot</id>
        <url>http://localhost:80/snapshots</url>
    </snapshotRepository>
</distributionManagement>
```
- `mvn clean deploy -DskipTests`
- code is attached.
[【附件】maven-reposilite-usage.zip](/media/attachment/2023/07/maven-reposilite-usage.zip)

##### conclusion

only use to publish jar to other users, can not be consider as private-server.

## mvnd

[mvn daemon](https://downloads.apache.org/maven/mvnd/)

## maven源码分析

- 版本3.6.3

可以修改$M2_HOME/conf/logging/simplelogger.properties
使日志内容更多（日志中显示时间/线程名/logger名
```
org.slf4j.simpleLogger.showDateTime=true
# 如下一行原simplelogger.properties中没有，看源码org.slf4j.impl.SimpleLoggerConfiguration#init才知道
org.slf4j.simpleLogger.dateTimeFormat=HH:mm:ss,SSS
org.slf4j.simpleLogger.showThreadName=true
org.slf4j.simpleLogger.showLogName=true
```

命令

```
# 打印info/warn/error日志
mvn clean package
# 打印debug/info/warn/error日志
mvn clean package -X
```

- 文件和类的对应
  * pom.xml --> ?
    - Project --> ?
    - Parent --> ?
    - Properties --> ?
- 对应一次请求：即一次mvn xxx命令，生命周期，Session MavenCli
  * 还有哪些类？