mybatis笔记

配置别名，将com.jt.pojo目录下的所有类封装为别名

也可以使用别名注解@Alieas("别名")

抽取公共sql

   
        select id,name,age,sex from demo_user
    

    
    
        
    

where set choose 标签用法

 
        select id,name,age,sex from demo_user
        
            name = #{name}
             and age=#{age}
             and sex=#{sex}
        
    

    
        update demo_user
        
            name =#{name}
             ,age=#{age}
             ,sex=#{sex}
        
        where id=#{id}
    

    
        select id,name,age,sex from demo_user
        
            
                name = #{name}
                sex = #{sex}
            
        
    

test文件

@Test//测试Where
    public void testFindWhere(){
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        DemoUserMapper demoUserMapper = sqlSession.getMapper(DemoUserMapper.class);
        DemoUser demoUser = new DemoUser();
        demoUser.setAge(3000);
        List list = demoUserMapper.findWhere(demoUser);
        System.out.println(list);
        sqlSession.close();
    }
    @Test//测试Set
    public void testSet(){
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        DemoUserMapper demoUserMapper = sqlSession.getMapper(DemoUserMapper.class);
        DemoUser demoUser = new DemoUser();
        demoUser.setAge(1000).setSex("男").setName("猴子").setId(50);
        demoUserMapper.updateSet(demoUser);
        sqlSession.close();
    }
    @Test//测试choose
    public void testChoose(){
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        DemoUserMapper demoUserMapper = sqlSession.getMapper(DemoUserMapper.class);
        DemoUser demoUser = new DemoUser();
        demoUser.setName("守山大使").setSex("男");
        List list = demoUserMapper.findChoose(demoUser);
        System.out.println(list);
        sqlSession.close();
    }

ResultType说明:
当结果集中的字段名称,如果与属性的名称一致时,才会实现自动的数据封装
ResultMap说明:
当结果集中的字段名称,与对象中的属性不一致时,可以使用result Map实现自定义的封装.

映射的结果集字段与表中的字段不一致时，使用resultMap属性和标签

dept_id => deptId;

dept_name => deptName;

    select * from dept