MAVEN 简单介绍

浅浅的花香味﹌ 2022-02-03 03:49 258阅读 0赞

** 基本结构**

**基本命令**

mvn -v 查看版本，检查是否按照成功
    mvn compile 编译Java文件，生成.class
    mvn test 执行测试用例
    mvn package 打包
    mvn clean 清除编译打包信息
    mvn install 安装当前项目到本地仓库中
    
    
    mvn install -DskipTests 跳过测试打包
    mvn clean package 先清除在打包

**相关特性**

传递依赖：项目中引用了一个jar包，jar中又引用了其他jar。编译时，maven会把直接引用和间接引用的jar都下载到本地。

排除依赖：

<dependency>
                <groupId>com.google.code.gson</groupId>
                <artifactId>gson</artifactId>
                <version>2.8.5</version>
                <exclusions>
                    <exclusion>
                        <groupId>commons-logging</groupId>
                        <artifactId>commons-logging</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>

**多模块聚合**

父模块的配置：（packaging 类型必须是pom）
    <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
         <version>2.1.4.RELEASE</version>
    </parent>
    
    子模块聚合
    <modules>
         <module>ad-eureka</module>
         <module>imooc-ad-service</module>
    </modules>
    
    父模块统一管理依赖包版本dependencyManagement
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot</artifactId>
                <version>2.1.4.RELEASE</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-test</artifactId>
                <version>2.1.4.RELEASE</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

**依赖冲突**

短路优先：(会使用k里面的m)
        x.jar->b.jar->m.jar
        k.jar->m.jar
    
    声明优先:(会使用前面x的m)
        x.jar->m.jar
        k.jar->m.jar
    
    这里处理的是相同版本的依赖，不同版本依赖，必须手动去排除

例子：spring cloud父类

<?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>com.stude</groupId>
        <artifactId>advertisement</artifactId>
        <version>1.0.0-SNAPSHOT</version>
    
        <name>advertisement</name>
        <description>Project for Imooc Ad SpringCloud</description>
    
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.1.4.RELEASE</version>
        </parent>
    
    
        <properties>
            
            <java.version>1.8</java.version>
            <spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.16.18</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
        </dependencies>
    
        
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud.dependencies</artifactId>
                    <version>${spring-cloud.version}}</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
    
        
        <repositories>
            <repository>
                <id>spring-milestones</id>
                <name>Spring Milestones</name>
                <url>https://repo.spring.io/milestone</url>
                <snapshots>
                    <enabled>false</enabled> 
                </snapshots>
            </repository>
        </repositories>
        
    </project>