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java1234初学maven

Maven 初学
2023-09-14 08:58:30 时间

 

第一讲：

maven
    maven是基于项目对象模型（POM），可以通过一小段描述信息来管理项目的构建，报告和文档的软件项目管理工具。
maven安装与下载：
    1、确定jdk已经安装并且配置
    2、安装maven
    3、配置maven环境变量：M2_HOME D:\maven\apache-maven-3.3.9 （就是maven的安装目录）
    
HelloWorld的实现
    modelVersion:POM模型版本4.0.0固定
    groupId：一般指某个公司或者某个组织的某个项目，比如org.springframework
    artifactId：一般指某个具体项目的某个具体模块，比如spring-context
    Version：项目的版本
    Maven常见命令：
        complie 编译
        clean 清空
        test 测试
        package 打包
        install 将项目安装到本地仓库
    Mvn远程仓库地址：http://mvnrepository.com/

 

第二讲，我的实践：

使用idea创建helloWorld的maven项目：

Mvn远程仓库地址：http://mvnrepository.com/ 这个很重要，我们的需要什么jar包都可以在上面搜寻坐标
idea的时候文件夹的颜色标识这个也重要，不然可能无法new出想要的file

然后就是测试各个maven命令：

第三讲：

maven仓库的概念：

Maven远程仓库配置文件：
$M2_HOME/lib/maven-model-builder-3.3.9jar
下的文件：org/apache/maven/model/pom-4.0.0.xml

-<repositories>

-<repository>

<id>central</id>

<name>Central Repository</name>

<url>https://repo.maven.apache.org/maven2</url>

<layout>default</layout>


-<snapshots>

<enabled>false</enabled>

</snapshots>

</repository>

</repositories>

 

maven依赖：
我们可以将一个项目install到本地仓库，然后本地其他项目引用这个项目，就是引用这个项目的下标，如：
<dependencies>
<dependency>
<groupId>com.java1234.user</groupId>
<artifactId>user-dao</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
</dependencies>
我们做个例子：
使用maven创建ssm项目的各个模块并且成功运行：
关键代码：

其实没有什么关键代码，就是ssm的整合搭建

 

依赖的特性：

　　最短路径原则和最先声明原则。就是如果A项目中引用了B和C项目，B中间接引用了F，C直接引用了F，那么A中引用F依赖是通过C来达到的，就近原则。当两边路径相等的时候，哪个项目被先引用就使用哪个项目得到依赖。

 

第四讲：

maven的聚合与继承：
聚合：
新的maven项目中，这样聚合其他项目：

<modules>
<module>../user-dao</module>
<module>../user-service</module>
</modules>
注意该项目中package只能为pom：
<packaging>pom</packaging>

作用：方便统一管理

继承：
继承实现：
新建父项目，然后在子项目坐标前加上继承描述：

<parent>
<groupId>com.java1234.user</groupId>
<artifactId>user-parent</artifactId>
<version>1.0-SNAPSHOT</version>
<relativePath>../user-parent/pom.xml</relativePath>
</parent>

relativePath一定要加上。

注意：一定要在子项目坐标前，然后就可以使用继承了。
方便版本版本管理与依赖管理
使用了继承子项目的groupId可以删掉了，默认使用的是父项目的groupId。默认状况下 version和packing也是继承父项目的，适当情况下可以省略不写。webapp项目注意packing不要省略，因为父项目一般是jar形式打包，webapp是war包
每个子项目中都有好多jar，它们可能太多的时候导致版本混乱，这样的话我们可以将这些依赖都假如到父类的dependency里面，然后子模块继承父模块可以省略子模块中的版本和scope。都使用父类的版本其他。

注意是放在dependencyManagement里面的dependencies里面添加依赖

<dependencyManagement>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
</dependencies>


可以在pom里面声明版本属性，然后在dependency里面应用它，我们常用来管理版本，使用方式看例子：

<properties>
<spring.version>4.3.5.RELEASE</spring.version>
<mybatis.version>3.4.1</mybatis.version>
</properties>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>

我再父项目中装载了其他的子项目，便于管理。使用的idea，感觉还是新建一个项目和新建其他模块比较好一点。虽然效果好像差不多。

 

最终的项目各模块的pom：
<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.java1234.user</groupId>
        <artifactId>user-parent</artifactId>
        <version>1.0-SNAPSHOT</version>
        <relativePath>../user-parent/pom.xml</relativePath>
    </parent>

  <artifactId>user-web</artifactId>
  <packaging>war</packaging>

  <name>user-web Maven Webapp</name>
  <url>http://maven.apache.org</url>

  <dependencies>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
    </dependency>

    <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
    </dependency>


    <!-- https://mvnrepository.com/artifact/javax.servlet.jsp/jsp-api -->
    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>jsp-api</artifactId>
    </dependency>



    <!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
    </dependency>



    <dependency>
      <groupId>com.java1234.user</groupId>
      <artifactId>user-service</artifactId>
      <version>1.0-SNAPSHOT</version>
    </dependency>


  </dependencies>

  <build>
    <finalName>user-web</finalName>
  </build>


</project>
user-web的pom
<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.java1234.user</groupId>
    <artifactId>user-parent</artifactId>
    <version>1.0-SNAPSHOT</version>
    <relativePath>../user-parent/pom.xml</relativePath>
  </parent>

  <artifactId>user-dao</artifactId>
  <packaging>jar</packaging>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
    </dependency>

    <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
    </dependency>
</dependencies>
</project>
user-dao的web
<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.java1234.user</groupId>
    <artifactId>user-parent</artifactId>
    <version>1.0-SNAPSHOT</version>
    <relativePath>../user-parent/pom.xml</relativePath>
  </parent>

  <artifactId>user-service</artifactId>
  <packaging>jar</packaging>


  <dependencies>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-context-support -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context-support</artifactId>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-aop -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aop</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-aspects -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aspects</artifactId>
    </dependency>


    <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
    </dependency>

    <dependency>
      <groupId>com.java1234.user</groupId>
      <artifactId>user-dao</artifactId>
      <version>1.0-SNAPSHOT</version>
    </dependency>



  </dependencies>



</project>
user-service的web
<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.java1234.user</groupId>
    <artifactId>user-parent</artifactId>
    <version>1.0-SNAPSHOT</version>
    <relativePath>../user-parent/pom.xml</relativePath>
  </parent>

  <artifactId>user-service</artifactId>
  <packaging>jar</packaging>


  <dependencies>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-context-support -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context-support</artifactId>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-aop -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aop</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-aspects -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aspects</artifactId>
    </dependency>


    <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
    </dependency>

    <dependency>
      <groupId>com.java1234.user</groupId>
      <artifactId>user-dao</artifactId>
      <version>1.0-SNAPSHOT</version>
    </dependency>



  </dependencies>



</project>
user-aggregator的pom
<?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.java1234.user</groupId>
    <artifactId>user-parent</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>

    <properties>
        <spring.version>4.3.5.RELEASE</spring.version>
        <mybatis.version>3.4.1</mybatis.version>
    </properties>

    <modules>
        <module>../user-dao</module>
        <module>../user-service</module>
        <module>../user-web</module>
    </modules>


    <dependencyManagement>
        <dependencies>
            <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <!-- https://mvnrepository.com/artifact/org.springframework/spring-context-support -->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context-support</artifactId>
                <version>${spring.version}</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-core</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-beans</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-web</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-webmvc</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-jdbc</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <!-- https://mvnrepository.com/artifact/org.springframework/spring-aop -->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-aop</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-tx</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <!-- https://mvnrepository.com/artifact/org.springframework/spring-aspects -->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-aspects</artifactId>
                <version>${spring.version}</version>
            </dependency>


            <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis-spring</artifactId>
                <version>1.3.0</version>
            </dependency>




            <!-- https://mvnrepository.com/artifact/junit/junit -->
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
            </dependency>


            <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>${mybatis.version}</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.36</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
            <dependency>
                <groupId>javax.servlet</groupId>
                <artifactId>javax.servlet-api</artifactId>
                <version>3.1.0</version>
            </dependency>


            <!-- https://mvnrepository.com/artifact/javax.servlet.jsp/jsp-api -->
            <dependency>
                <groupId>javax.servlet.jsp</groupId>
                <artifactId>jsp-api</artifactId>
                <version>2.2</version>
            </dependency>



            <!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->
            <dependency>
                <groupId>javax.servlet</groupId>
                <artifactId>jstl</artifactId>
                <version>1.2</version>
            </dependency>


        </dependencies>

    </dependencyManagement>


</project>
user-parent的pom

 

 

 

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