【MyBatis笔记】使用注解开发_java

在方法前使用注解的方式

绑定接口到核心配置文件中:

本质：使用反射

底层：动态代理

使用注解进行增删改查：

自动提交事务：

工具类：

public interface UserMapper {

    @Select("select * from user")
    //获取全部用户
    ListgetUser();


//    ---------------------------------------------
    //方法存在多个参数，所有的参数前面必须加上@Param("")
    @Select("select * from user where id=#{id}")
    //获取id获取用户
    User getUserById(@Param("id") int id);
//  ------------------------------------------------

    @Insert("insert into user(id,name,pwd) values(#{id},#{name},#{pwd})")
    int addUser(User user);

// ---------------------------------------------------

    @Update("update user set name=#{name},pwd=#{pwd} where id=#{id}")
    int updateUser(Mapmap);
//------------------------------------------------------

    @Delete("delete from user where id=#{id}")
    int deleteUser(@Param("id")int id);
}

public class User {
    private int id;
    private String name;
    private String pwd;
    getter setter tostring;
}

测试类

    @Test
    public void getUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List user = mapper.getUser();
        for (User user1 : user) {
            System.out.println(user1);
        }
        sqlSession.close();
    }
    @Test
    public void getUserById(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User userById = mapper.getUserById(2);
        System.out.println(userById);
        sqlSession.close();
    }
    @Test
    public void addUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.addUser(new User(6,"哈哈哈是的","76543"));
        sqlSession.close();
    }
    @Test
    public void updateUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        HashMap map = new HashMap<>();
        map.put("id",2);
        map.put("name","2two");
        map.put("pwd","lasf");
        mapper.updateUser(map);
        sqlSession.close();
    }
    @Test
    public void delete(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        mapper.deleteUser(2);
        sqlSession.close();
    }

Mybatis详细执行流程：