Mybatis逆向工程

1、Mybatis 逆向工程是什么？

MyBatis Generator

简称mbg,是一个专门为Mybatis框架使用者定制的代码生成器，可以快速的根据表生成对应的

映射文件、接口和bean类。支持基本的增删改查，以及QBC（Query By Criteria）风格的条件查询。

2、如何使用

首先说一下，以下配置必须放在一个完整的mybatis项目下，别犯傻哈！

(即引入了mybatis相关的jar包和 具备mybatis全局配置文件）

1）导入mybatis逆向工程相应的jar包

2）编写全局配置文件mbg.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="MyBatis3Simple":生成简单版的CRUD
        MyBatis3:豪华版

     -->
    <context id="DB2Tables" targetRuntime="MyBatis3">
        <!-- jdbcConnection：指定如何连接到目标数据库 -->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/mybatis?allowMultiQueries=true"
                        userId="root"
                        password="houchen">
        </jdbcConnection>

        <!--  -->
        <javaTypeResolver >
            <property name="forceBigDecimals" value="false" />
        </javaTypeResolver>

        <!-- javaModelGenerator：指定javaBean的生成策略
        targetPackage="test.model"：目标包名
        targetProject="MBGTestProjectsrc"：目标工程
        -->
        <javaModelGenerator targetPackage="com.atguigu.mybatis.bean"
                            targetProject=".src">
            <property name="enableSubPackages" value="true" />
            <property name="trimStrings" value="true" />
        </javaModelGenerator>

        <!-- sqlMapGenerator：sql映射生成策略： -->
        <sqlMapGenerator targetPackage="com.atguigu.mybatis.dao"
                         targetProject=".conf">
            <property name="enableSubPackages" value="true" />
        </sqlMapGenerator>

        <!-- javaClientGenerator:指定mapper接口所在的位置 -->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.atguigu.mybatis.dao"
                             targetProject=".src">
            <property name="enableSubPackages" value="true" />
        </javaClientGenerator>

        <!-- 指定要逆向分析哪些表：根据表要创建javaBean -->
        <table tableName="tbl_dept" domainObjectName="Department"></table>
        <table tableName="tbl_employee" domainObjectName="Employee"></table>
    </context>
</generatorConfiguration>

<?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="MyBatis3Simple":生成简单版的CRUD
        MyBatis3:豪华版

     -->
    <context id="DB2Tables" targetRuntime="MyBatis3">
        <!-- jdbcConnection：指定如何连接到目标数据库 -->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/mybatis?allowMultiQueries=true"
                        userId="root"
                        password="houchen">
        </jdbcConnection>

        <!--  -->
        <javaTypeResolver >
            <property name="forceBigDecimals" value="false" />
        </javaTypeResolver>

        <!-- javaModelGenerator：指定javaBean的生成策略
        targetPackage="test.model"：目标包名
        targetProject="MBGTestProjectsrc"：目标工程
        -->
        <javaModelGenerator targetPackage="com.atguigu.mybatis.bean"
                            targetProject=".src">
            <property name="enableSubPackages" value="true" />
            <property name="trimStrings" value="true" />
        </javaModelGenerator>

        <!-- sqlMapGenerator：sql映射生成策略： -->
        <sqlMapGenerator targetPackage="com.atguigu.mybatis.dao"
                         targetProject=".conf">
            <property name="enableSubPackages" value="true" />
        </sqlMapGenerator>

        <!-- javaClientGenerator:指定mapper接口所在的位置 -->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.atguigu.mybatis.dao"
                             targetProject=".src">
            <property name="enableSubPackages" value="true" />
        </javaClientGenerator>

        <!-- 指定要逆向分析哪些表：根据表要创建javaBean -->
        <table tableName="tbl_dept" domainObjectName="Department"></table>
        <table tableName="tbl_employee" domainObjectName="Employee"></table>
    </context>
</generatorConfiguration>

3) 测试逆向工程

@Test
public void testMybatisGenerate() throws Exception {
    List<String> warnings = new ArrayList<String>();
    boolean overwrite = true;
    File configFile = new File("mbg.xml");
    ConfigurationParser cp = new ConfigurationParser(warnings);
    Configuration config = cp.parseConfiguration(configFile);
    DefaultShellCallback callback = new DefaultShellCallback(overwrite);
    MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config,
            callback, warnings);
    myBatisGenerator.generate(null);
}

确实生成了相应的实体、接口和 mapper: