maven学习（3）-Maven 核心技术

2022-01-20 00:09:14

第一节：Maven 仓库概念

Maven 远程仓库配置文件：

$M2_HOME/lib/maven-model-builder-3.3.3.jar

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>

可以看到是从这里找的：

https://repo.maven.apache.org/maven2/

第二节：Maven 依赖特性

依赖传递和依赖选择：

user-service依赖于spring-core,spring-core依赖于commons-logging,user-service也就依赖于commons-logging

A->B->-C->X，A依赖X，路径为三层，A->D->X，A也依赖X，路径为两层，这时只会下载A->D->X中的X jar包，不然jar包就重复了；

但是假设路径都一样，A->B->X和A->C->X,最先声明原则，只会下载A->B->X的Xjar包，后面A->C->X就不会再下载X了；

三、下面是一个例子

我们构建一个user项目（这里还是java项目jar，不是web），user项目分为两个模块，user-dao和user-service，

后面user-service中要使用到user-dao中的类等。

1.先建user-dao项目:

使用mybatis，log4j等，工程结构：

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-dao</artifactId>

  <version>0.0.1-SNAPSHOT</version>

  <packaging>jar</packaging>

  <properties>

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

  </properties>

  <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>1.2.17</version>

    </dependency>

    <dependency>

      <groupId>junit</groupId>

      <artifactId>junit</artifactId>

      <version>4.12</version>

      <scope>test</scope>

    </dependency>

  </dependencies>

</project>

UserDao.java:

package com.cy.user.dao;

import com.cy.user.entity.User;

public interface UserDao {

    public User login(User user);

}

User.java:

package com.cy.user.entity;

/**

 * 用户实体

 * @author Administrator

 *

 */

public class User {

    private Integer id; // 编号

    private String userName; // 用户名

    private String password; // 密码

    public Integer getId() {

        return id;

    }

    public void setId(Integer id) {

        this.id = id;

    }

    public String getUserName() {

        return userName;

    }

    public void setUserName(String userName) {

        this.userName = userName;

    }

    public String getPassword() {

        return password;

    }

    public void setPassword(String password) {

        this.password = password;

    }

}

UserMapper.xml:

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE mapper

PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.cy.user.dao.UserDao">

    <select id="login" parameterType="User" resultType="User">

        select * from t_user where userName=#{userName} and password=#{password}

    </select>

</mapper>

log4j.properties:

log4j.rootLogger=DEBUG, Console  

#Console

log4j.appender.Console=org.apache.log4j.ConsoleAppender

log4j.appender.Console.layout=org.apache.log4j.PatternLayout

log4j.appender.Console.layout.ConversionPattern=%d [%t] %-5p [%c] - %m%n  

log4j.logger.java.sql.ResultSet=INFO

log4j.logger.org.apache=INFO

log4j.logger.java.sql.Connection=DEBUG

log4j.logger.java.sql.Statement=DEBUG

log4j.logger.java.sql.PreparedStatement=DEBUG

mybatis-config.xml:

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE configuration

PUBLIC "-//mybatis.org//DTD Config 3.0//EN"

"http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>

    <!-- 别名 -->

    <typeAliases>

        <package name="com.cy.user.entity"/>

    </typeAliases>

</configuration>

因为后面user-service中要使用user-dao这个模块，所以，将user-dao发布到本地仓库，pom.xml上右击Run as --》Maven install, 发布完之后，在targe下可以看到：

/user-dao/target/user-dao-0.0.1-SNAPSHOT.jar

2.新建user-service项目

工程结构：

pom.xml:

因为和user-dao集成，要使用user类，UserDao等，所以将user-dao添加到依赖；

可以在Maven Dependencies下面看到user-dao作为一个jar被引进来了。

<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>

  <groupId>com.cy.user</groupId>

  <artifactId>user-service</artifactId>

  <version>0.0.1-SNAPSHOT</version>

  <packaging>jar</packaging>

  <properties>

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

  </properties>

  <dependencies>

      <dependency>

          <groupId>org.springframework</groupId>

          <artifactId>spring-core</artifactId>

          <version>4.1.7.RELEASE</version>

      </dependency>

      <dependency>

          <groupId>org.springframework</groupId>

          <artifactId>spring-beans</artifactId>

          <version>4.1.7.RELEASE</version>

      </dependency>

      <dependency>

         <groupId>org.springframework</groupId>

         <artifactId>spring-tx</artifactId>

         <version>4.1.7.RELEASE</version>

        </dependency>

      <dependency>

          <groupId>org.springframework</groupId>

          <artifactId>spring-context</artifactId>

          <version>4.1.7.RELEASE</version>

      </dependency>

      <dependency>

          <groupId>org.springframework</groupId>

          <artifactId>spring-context-support</artifactId>

          <version>4.1.7.RELEASE</version>

      </dependency>

      <dependency>

        <groupId>org.springframework</groupId>

        <artifactId>spring-web</artifactId>

        <version>4.1.7.RELEASE</version>

    </dependency>

      <dependency>

        <groupId>org.springframework</groupId>

        <artifactId>spring-webmvc</artifactId>

        <version>4.1.7.RELEASE</version>

    </dependency>

    <dependency>

        <groupId>org.springframework</groupId>

        <artifactId>spring-aop</artifactId>

        <version>4.1.7.RELEASE</version>

    </dependency>

    <dependency>

        <groupId>org.springframework</groupId>

        <artifactId>spring-aspects</artifactId>

        <version>4.1.7.RELEASE</version>

    </dependency>

    <dependency>

        <groupId>org.springframework</groupId>

        <artifactId>spring-jdbc</artifactId>

        <version>4.1.7.RELEASE</version>

    </dependency>

    <dependency>

        <groupId>org.mybatis</groupId>

        <artifactId>mybatis-spring</artifactId>

        <version>1.2.3</version>

    </dependency>

    <dependency>

      <groupId>junit</groupId>

      <artifactId>junit</artifactId>

      <version>4.12</version>

      <scope>test</scope>

    </dependency>

    <dependency>

        <groupId>com.cy.user</groupId>

        <artifactId>user-dao</artifactId>

        <version>0.0.1-SNAPSHOT</version>

    </dependency>

  </dependencies>

</project>

UserService.java:

package com.cy.user.service;

import com.cy.user.entity.User;

/**

 * 用户Service接口

 * @author Administrator

 *

 */

public interface UserService {

    public User login(User user);

}

UserServiceImpl.java:

package com.cy.user.service.impl;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import com.cy.user.dao.UserDao;

import com.cy.user.entity.User;

import com.cy.user.service.UserService;

/**

 * 用户Service实现类

 * @author Administrator

 *

 */

@Service("userService")

public class UserServiceImpl implements UserService{

    @Autowired

    private UserDao userDao;

    public User login(User user) {

        return userDao.login(user);

    }

}

applicationContext.xml:

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xmlns:p="http://www.springframework.org/schema/p"

    xmlns:aop="http://www.springframework.org/schema/aop"

    xmlns:context="http://www.springframework.org/schema/context"

    xmlns:jee="http://www.springframework.org/schema/jee"

    xmlns:tx="http://www.springframework.org/schema/tx"

    xsi:schemaLocation="

        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd

        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd

        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd

        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-4.0.xsd

        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">    

    <!-- 自动扫描 -->

    <context:component-scan base-package="com.cy.user.service" />

    <!-- 配置数据源 -->

    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">

        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>

        <property name="url" value="jdbc:mysql://localhost:3306/db_maven"/>

        <property name="username" value="root"/>

        <property name="password" value="root"/>

    </bean>

    <!-- 配置mybatis的sqlSessionFactory -->

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">

        <property name="dataSource" ref="dataSource" />

        <!-- 自动扫描mappers.xml文件 -->

        <property name="mapperLocations" value="classpath:com/cy/user/mappers/*.xml"></property>

        <!-- mybatis配置文件 -->

        <property name="configLocation" value="classpath:mybatis-config.xml"></property>

    </bean>

    <!-- DAO接口所在包名，Spring会自动查找其下的类 -->

    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">

        <property name="basePackage" value="com.cy.user.dao" />

        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>

    </bean>

    <!-- (事务管理)transaction manager, use JtaTransactionManager for global tx -->

    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">

        <property name="dataSource" ref="dataSource" />

    </bean>

    <!-- 配置事务通知属性 -->

    <tx:advice id="txAdvice" transaction-manager="transactionManager">

        <!-- 定义事务传播属性 -->

        <tx:attributes>

            <tx:method name="insert*" propagation="REQUIRED" />

            <tx:method name="update*" propagation="REQUIRED" />

            <tx:method name="edit*" propagation="REQUIRED" />

            <tx:method name="save*" propagation="REQUIRED" />

            <tx:method name="add*" propagation="REQUIRED" />

            <tx:method name="new*" propagation="REQUIRED" />

            <tx:method name="set*" propagation="REQUIRED" />

            <tx:method name="remove*" propagation="REQUIRED" />

            <tx:method name="delete*" propagation="REQUIRED" />

            <tx:method name="change*" propagation="REQUIRED" />

            <tx:method name="check*" propagation="REQUIRED" />

            <tx:method name="get*" propagation="REQUIRED" read-only="true" />

            <tx:method name="find*" propagation="REQUIRED" read-only="true" />

            <tx:method name="load*" propagation="REQUIRED" read-only="true" />

            <tx:method name="*" propagation="REQUIRED" read-only="true" />

        </tx:attributes>

    </tx:advice>  

    <!-- 配置事务切面 -->

    <aop:config>

        <aop:pointcut id="serviceOperation" expression="execution(* com.cy.user.service.*.*(..))" />

        <aop:advisor advice-ref="txAdvice" pointcut-ref="serviceOperation" />

    </aop:config>  

</beans>

还没有完，上面主要就是演示user-service中来依赖user-dao，user-dao需要发布到本地仓库；

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第三节：Maven 聚合与继承特性

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码农公寓

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