MyBatis 逆向工程

一、逆向工程简介

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，以及bean类。支持基本的增删改查，以及QBC风格的条件查询。但是表连接、存储过程等这些复杂sql的定义需要我们手工编写
官方文档地址
​​​ http://www.mybatis.org/generator/​​​ 官方工程地址
https://github.com/mybatis/generator/releases

二、逆向工程的配置

1)导入逆向工程的jar包
mybatis-generator-core-1.3.2.jar
2)编写MBG的配置文件（重要几处配置）,可参考官方手册

<?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: 执行生成的逆向工程的版本
          MyBatis3Simple: 生成基本的CRUD
          MyBatis3: 生成带条件的CRUD
   -->
  <context id="DB2Tables" targetRuntime="MyBatis3">
  
    <jdbcConnection driverClass="com.mysql.jdbc.Driver"
        connectionURL="jdbc:mysql://localhost:3306/mybatis_1129"
        userId="root"
        password="1234">
    </jdbcConnection>
  <!-- javaBean的生成策略-->
    <javaModelGenerator targetPackage="com.atguigu.mybatis.beans" targetProject=".\src">
      <property name="enableSubPackages" value="true" />
      <property name="trimStrings" value="true" />
    </javaModelGenerator>
  <!-- SQL映射文件的生成策略 -->
    <sqlMapGenerator targetPackage="com.atguigu.mybatis.dao"  targetProject=".\conf">
      <property name="enableSubPackages" value="true" />
    </sqlMapGenerator>
  
  <!-- Mapper接口的生成策略 -->
    <javaClientGenerator type="XMLMAPPER" targetPackage="com.atguigu.mybatis.dao"  targetProject=".\src">
      <property name="enableSubPackages" value="true" />
    </javaClientGenerator>
  <!-- 逆向分析的表 -->
    <table tableName="tbl_dept" domainObjectName="Department"></table>
    <table tableName="tbl_employee" domainObjectName="Employee"></table>
  </context>
</generatorConfiguration>

3)运行代码生成器生成代码

@Test
public void testMBG() 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);
}

三、逆向工程的使用

基本查询的测试

@Test
  public void testSelect() throws Exception {
    SqlSessionFactory ssf = getSqlSessionFactory();
    SqlSession session = ssf.openSession();
    
    try {
      EmployeeMapper mapper = session.getMapper(EmployeeMapper.class);
      List<Employee> emps = mapper.selectAll();
      for (Employee employee : emps) {
        System.out.println(employee);
      }
    } finally {
      session.close();
    }
}

  public SqlSessionFactory getSqlSessionFactory() throws Exception{
    String resource = "mybatis-config.xml";
    InputStream in = Resources.getResourceAsStream(resource);
    SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
    return sqlSessionFactory;
  }