mybatis逆向工程基础版

1. 基本介绍  120

介绍所谓的逆向⼯程是：根据数据库表逆向⽣成Java的pojo类，SqlMapper.xml⽂件，以及Mapper接⼝类等。要完成这个⼯作，需要借助别⼈写好的逆向⼯程插件。

思考：使⽤这个插件的话，需要给这个插件配置哪些信息？

● pojo类名、包名以及⽣成位置。

● SqlMapper.xml⽂件名以及⽣成位置。

● Mapper接⼝名以及⽣成位置。

● 连接数据库的信息。

● 指定哪些表参与逆向⼯程。

● ......

2. 逆向⼯程配置与⽣成  121

2.1 第⼀步：基础环境准备

新建模块

打包⽅式：jar

2.2 第⼆步：在pom中添加逆向⼯程插件

<!--配置mybatis逆向工程的插件-->
    <!--定制构建过程-->
    <build>
        <!--可配置多个插件-->
        <plugins>
            <!--其中的一个插件：mybatis逆向工程插件-->
            <plugin>
                <!--插件的GAV坐标-->
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.4.1</version>
                <!--允许覆盖-->
                <configuration>
                    <overwrite>true</overwrite>
                </configuration>
                <!--插件的依赖-->
                <dependencies>
                    <!--mysql驱动依赖-->
                    <dependency>
                        <groupId>mysql</groupId>
                        <artifactId>mysql-connector-java</artifactId>
                        <version>8.0.30</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>

2.3 第三步：配置generatorConfig.xml

该⽂件名必须叫做：generatorConfig.xml

该⽂件必须放在类的根路径下。

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>
    <!--
        targetRuntime有两个值：
            MyBatis3Simple：生成的是基础版，只有基本的增删改查。
            MyBatis3：生成的是增强版，除了基本的增删改查之外还有复杂的增删改查。
    -->
    <context id="DB2Tables" targetRuntime="MyBatis3Simple">
        <!--防止生成重复代码-->
        <plugin type="org.mybatis.generator.plugins.UnmergeableXmlMappersPlugin"/>

        <commentGenerator>
            <!--是否去掉生成日期-->
            <property name="suppressDate" value="true"/>
            <!--是否去除注释-->
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>

        <!--连接数据库信息-->
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/powernode"
                        userId="root"
                        password="root">
        </jdbcConnection>

        <!-- 生成pojo包名和位置 -->
        <javaModelGenerator targetPackage="com.powernode.mybatis.pojo" targetProject="src/main/java">
            <!--是否开启子包-->
            <property name="enableSubPackages" value="true"/>
            <!--是否去除字段名的前后空白-->
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>

        <!-- 生成SQL映射文件的包名和位置 -->
        <sqlMapGenerator targetPackage="com.powernode.mybatis.mapper" targetProject="src/main/resources">
            <!--是否开启子包-->
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>

        <!-- 生成Mapper接口的包名和位置 -->
        <javaClientGenerator
                type="xmlMapper"
                targetPackage="com.powernode.mybatis.mapper"
                targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>

        <!-- 表名和对应的实体类名-->
        <table tableName="t_car" domainObjectName="Car"/>

    </context>
</generatorConfiguration>

第四步：运⾏插件

双击红框选项即可生成pojo的Car   接口CarMapper   SQL映射文件CarMapper.xml

3. 测试逆向⼯程⽣成的是否好⽤  122

3.1 准备环境  121

依赖：mybatis依赖、mysql驱动依赖、junit依赖、logback依赖

jdbc.properties

mybatis-config.xml

 logback.xml

3.2 编写测试程序  122

//根据主键删除
    @Test
    public void testDeleteByPrimaryKey(){
        SqlSession sqlSession = SqlSessionUtil.openSession();
        CarMapper mapper = sqlSession.getMapper(CarMapper.class);
        int count = mapper.deleteByPrimaryKey(38L);
        System.out.println(count);
        sqlSession.commit();
        sqlSession.close();
    }

//查询所有
    @Test
    public void testSelectAll(){
        SqlSession sqlSession = SqlSessionUtil.openSession();
        CarMapper mapper = sqlSession.getMapper(CarMapper.class);
        List<Car> cars = mapper.selectAll();
        cars.forEach(car -> System.out.println(car));
        sqlSession.close();
    }

4. 代码汇总

main中com.powernode.mybatis.mapper

CarMapper

package com.powernode.mybatis.mapper;

import com.powernode.mybatis.pojo.Car;
import java.util.List;

public interface CarMapper {
    int deleteByPrimaryKey(Long id);

    int insert(Car row);

    Car selectByPrimaryKey(Long id);

    List<Car> selectAll();

    int updateByPrimaryKey(Car row);
}

CarMapper.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.powernode.mybatis.mapper.CarMapper">
  <resultMap id="BaseResultMap" type="com.powernode.mybatis.pojo.Car">
    <id column="id" jdbcType="BIGINT" property="id" />
    <result column="car_num" jdbcType="VARCHAR" property="carNum" />
    <result column="brand" jdbcType="VARCHAR" property="brand" />
    <result column="guide_price" jdbcType="DECIMAL" property="guidePrice" />
    <result column="produce_time" jdbcType="CHAR" property="produceTime" />
    <result column="car_type" jdbcType="VARCHAR" property="carType" />
  </resultMap>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Long">
    delete from t_car
    where id = #{id,jdbcType=BIGINT}
  </delete>
  <insert id="insert" parameterType="com.powernode.mybatis.pojo.Car">
    insert into t_car (id, car_num, brand, 
      guide_price, produce_time, car_type
      )
    values (#{id,jdbcType=BIGINT}, #{carNum,jdbcType=VARCHAR}, #{brand,jdbcType=VARCHAR}, 
      #{guidePrice,jdbcType=DECIMAL}, #{produceTime,jdbcType=CHAR}, #{carType,jdbcType=VARCHAR}
      )
  </insert>
  <update id="updateByPrimaryKey" parameterType="com.powernode.mybatis.pojo.Car">
    update t_car
    set car_num = #{carNum,jdbcType=VARCHAR},
      brand = #{brand,jdbcType=VARCHAR},
      guide_price = #{guidePrice,jdbcType=DECIMAL},
      produce_time = #{produceTime,jdbcType=CHAR},
      car_type = #{carType,jdbcType=VARCHAR}
    where id = #{id,jdbcType=BIGINT}
  </update>
  <select id="selectByPrimaryKey" parameterType="java.lang.Long" resultMap="BaseResultMap">
    select id, car_num, brand, guide_price, produce_time, car_type
    from t_car
    where id = #{id,jdbcType=BIGINT}
  </select>
  <select id="selectAll" resultMap="BaseResultMap">
    select id, car_num, brand, guide_price, produce_time, car_type
    from t_car
  </select>
</mapper>

test中com.powernode.mybatis.test

CarMapperTest

package com.powernode.mybatis.test;

import com.powernode.mybatis.mapper.CarMapper;
import com.powernode.mybatis.pojo.Car;
import com.powernode.mybatis.utils.SqlSessionUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

//测试mybatis逆向工程  122
public class CarMapperTest {

    //查询所有
    @Test
    public void testSelectAll(){
        SqlSession sqlSession = SqlSessionUtil.openSession();
        CarMapper mapper = sqlSession.getMapper(CarMapper.class);
        List<Car> cars = mapper.selectAll();
        cars.forEach(car -> System.out.println(car));
        sqlSession.close();
    }

    //根据主键删除
    @Test
    public void testDeleteByPrimaryKey(){
        SqlSession sqlSession = SqlSessionUtil.openSession();
        CarMapper mapper = sqlSession.getMapper(CarMapper.class);
        int count = mapper.deleteByPrimaryKey(38L);
        System.out.println(count);
        sqlSession.commit();
        sqlSession.close();
    }
}

generatorConfig.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>
    <!--
        targetRuntime有两个值：
            MyBatis3Simple：生成的是基础版，只有基本的增删改查。
            MyBatis3：生成的是增强版，除了基本的增删改查之外还有复杂的增删改查。
    -->
    <context id="DB2Tables" targetRuntime="MyBatis3Simple">
        <!--防止生成重复代码-->
        <plugin type="org.mybatis.generator.plugins.UnmergeableXmlMappersPlugin"/>

        <commentGenerator>
            <!--是否去掉生成日期-->
            <property name="suppressDate" value="true"/>
            <!--是否去除注释-->
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>

        <!--连接数据库信息-->
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/powernode"
                        userId="root"
                        password="lzl">
        </jdbcConnection>

        <!-- 生成pojo包名和位置 -->
        <javaModelGenerator targetPackage="com.powernode.mybatis.pojo" targetProject="src/main/java">
            <!--是否开启子包-->
            <property name="enableSubPackages" value="true"/>
            <!--是否去除字段名的前后空白-->
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>

        <!-- 生成SQL映射文件的包名和位置 -->
        <sqlMapGenerator targetPackage="com.powernode.mybatis.mapper" targetProject="src/main/resources">
            <!--是否开启子包-->
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>

        <!-- 生成Mapper接口的包名和位置 -->
        <javaClientGenerator
                type="xmlMapper"
                targetPackage="com.powernode.mybatis.mapper"
                targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>

        <!-- 表名和对应的实体类名-->
        <table tableName="t_car" domainObjectName="Car"/>

    </context>
</generatorConfiguration>

pom.xml

<?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.powernode</groupId>
    <artifactId>course23</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.10</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.2.11</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.30</version>
        </dependency>
    </dependencies>

    <properties>
        <!--    编译代码使用的jdk版本-->
        <maven.compiler.source>1.8</maven.compiler.source>
        <!--    运行程序使用的jdk版本-->
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <!--配置mybatis逆向工程的插件-->
    <!--定制构建过程-->
    <build>
        <!--可配置多个插件-->
        <plugins>
            <!--其中的一个插件：mybatis逆向工程插件-->
            <plugin>
                <!--插件的GAV坐标-->
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.4.1</version>
                <!--允许覆盖-->
                <configuration>
                    <overwrite>true</overwrite>
                </configuration>
                <!--插件的依赖-->
                <dependencies>
                    <!--mysql驱动依赖-->
                    <dependency>
                        <groupId>mysql</groupId>
                        <artifactId>mysql-connector-java</artifactId>
                        <version>8.0.30</version>
                    </dependency>
                </dependencies>
            </plugin>
        </plugins>
    </build>


</project>

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>
    <properties resource="jdbc.properties"/>
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>
    <typeAliases>
        <package name="com.powernode.mybatis.pojo"/>
    </typeAliases>
    <environments default="dev">
        <environment id="dev">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <package name="com.powernode.mybatis.mapper"/>
    </mappers>
</configuration>

剩余的

pojo

utils

logback.xml

jdbc.properties

不做赘述