maven学习（5）-Maven 聚合与继承特性

接着上面的项目，

继承和聚合为了统一管理；
聚合：
有些项目中有很多小模块，可以合并到一起，将多个子项目可以统一管理，可以对user-dao，user-service进行统一管理（maven clean等。。），编译，测试等；使用modules把多个模块写进去；
继承：
可以看到user-service和user-web这两个项目里面pom添加的jar包，spring的jar包很多一样，版本一样，
很多重复了；
版本号都一样了，可以搞一个父类，然后将这些版本信息统一管理；不然项目多的话，版本多起来也是挺复杂；
 
新建user-parent项目，对user-dao和user-service统一管理（聚合），同时对user-dao和user-service、user-web中的jar进行统一版本管理：
新建user-parent，只要有一个pom.xml就行了，所以new maven project，create a simple project（跳过一些骨架选项）；
group id： com.cy.user
artifact id：user-parent
version：0.0.1-SNAPSHOT
packaging：pom
 
user-parent项目下，只有一个pom.xml就行了：
 
将user-dao、user-service、user-web中的依赖包都复制到user-parent中来，统一定义版本；user-dao、service、web项目pom.xml就不需要写版本号了；
 
 
pom.xml:
<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.cy.user</groupId>
  <artifactId>user-parent</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>pom</packaging>
  
  <modules>
      <module>../user-dao</module>
      <module>../user-service</module>
  </modules>
  
  <properties>
      <spring.version>4.1.7.RELEASE</spring.version>
      <junit.version>4.12</junit.version>
      <log4j.version>1.2.17</log4j.version>
  </properties>
  
  <dependencyManagement>
      <dependencies>
          <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.3.0</version>
        </dependency>
          
          <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.22</version>
        </dependency>
        
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        
        <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>${junit.version}</version>
          <scope>test</scope>
        </dependency>
        
        <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-core</artifactId>
              <version>${spring.version}</version>
          </dependency>
          <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-beans</artifactId>
              <version>${spring.version}</version>
          </dependency>
          <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-tx</artifactId>
             <version>${spring.version}</version>
            </dependency>
          <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-context</artifactId>
              <version>${spring.version}</version>
          </dependency>
          <dependency>
              <groupId>org.springframework</groupId>
              <artifactId>spring-context-support</artifactId>
              <version>${spring.version}</version>
          </dependency>
          <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
          <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>1.2.3</version>
        </dependency>
        
        <!-- 添加Servlet支持 -->
          <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
        </dependency>
          
          <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>javax.servlet.jsp-api</artifactId>
            <version>2.3.1</version>
        </dependency>
        
        <!-- 添加jstl支持 -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
      </dependencies>
      
  </dependencyManagement>
  
</project>

user-dao/pom.xml:

<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>
    
  <parent>
      <groupId>com.cy.user</groupId>
     <artifactId>user-parent</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <relativePath>../user-parent/pom.xml</relativePath>
  </parent>        
    
  <artifactId>user-dao</artifactId>
  <packaging>jar</packaging>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
      <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
    </dependency>
      
      <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
    
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
    </dependency>
    
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>
</project>

user-service/pom.xml就变成了：

<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>
    
  <parent>
      <groupId>com.cy.user</groupId>
     <artifactId>user-parent</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <relativePath>../user-parent/pom.xml</relativePath>
  </parent>        
    
  <artifactId>user-service</artifactId>
  <packaging>jar</packaging>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-core</artifactId>
      </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-beans</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-tx</artifactId>
        </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context</artifactId>
      </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context-support</artifactId>
      </dependency>
      <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
    </dependency>
      <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aspects</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
    </dependency>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis-spring</artifactId>
    </dependency>
  
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <scope>test</scope>
    </dependency>
    
    <dependency>
        <groupId>com.cy.user</groupId>
        <artifactId>user-dao</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </dependency>
  </dependencies>
</project>

user-web/pom.xml就变成了：

<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/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  
  <parent>
      <groupId>com.cy.user</groupId>
     <artifactId>user-parent</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <relativePath>../user-parent/pom.xml</relativePath>
  </parent>    
  
  <artifactId>user-web</artifactId>
  <packaging>war</packaging><!-- 默认是jar，web项目是war -->

  <dependencies>
      <!-- 添加Servlet支持 -->
      <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
    </dependency>
      
      <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>javax.servlet.jsp-api</artifactId>
    </dependency>
    
    <!-- 添加jstl支持 -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
    </dependency>
      
      <!-- 添加Spring支持 -->
    <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-core</artifactId>
      </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-beans</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework</groupId>
         <artifactId>spring-tx</artifactId>
        </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context</artifactId>
      </dependency>
      <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context-support</artifactId>
      </dependency>
      
      <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
    </dependency>
    
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
    </dependency>
  
      <dependency>
          <groupId>com.cy.user</groupId>
          <artifactId>user-service</artifactId>
          <version>0.0.1-SNAPSHOT</version>
      </dependency>
  
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>
  <build>
    <finalName>user-web</finalName>
  </build>
</project>
查看项目下的maven dependencies依赖jar包，版本都是从user-parent继承下来的；
 
运行项目，http://localhost:8080/user-web/index.jsp，正常访问ok；
 
tips：
运行项目出了点问题，把user-dao下面的com.cy.user.mappers包移到src/main/resources下面去了；因为xml不是java文件，编译的时候没编译进去，插件支持的不是很好；
 
 
 
 
 
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原文地址：https://www.cnblogs.com/tenWood/p/8638434.html