Mybatis03-在02的基础上再实现CRUD

架构：

实体类，工具类和mybatis-config.xml和02一样，不用改了。要实现其他业务代码，主要修改UserMapper.xml

import java.util.List;

public interface UserDao {
    List getUser();//查询所有用户信息
    User getUserByID(int id);//根据ID查询用户
    int addUser(User user);//插入用户
    int deleteUser(int id);
    int updateUser(User user);
}

    
        select * from mybatis.user
    

    
        select * from mybatis.user where id=#{id}
    
    
    
        insert  into mybatis.user(id, name, pwd) VALUES (#{id},#{name},#{pwd})
    

    
        update mybatis.user set user.name=#{name},user.pwd=#{pwd} where id=#{id}
    

    
        delete  from user where id=#{id}
    

import java.util.List;


public class UserDaoTest  {
    @Test
    public  void userdaotest(){
        //1.获取SqlSession对象
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        //2.方式一:getMapper
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        List user = userDao.getUser();
        for (User user1 : user) {
            System.out.println(user1);
        }
        //3.关闭sqlSession
        sqlSession.close();
    }
    @Test
    public  void getUserByID(){
        //1.获取SqlSession对象
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        //2.方式一:getMapper
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        User user = userDao.getUserByID(1);
        System.out.println(user);
        //3.关闭sqlSession
        sqlSession.close();
    }
    //注意：增删改必须提交事务
    @Test
    public  void addUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        int wuyu = userDao.addUser(new User(4, "xiaoxing", "12123"));
        if(wuyu>0){
            System.out.println("插入成功");
        }
        sqlSession.commit();//提交事务
        sqlSession.close();
    }
    @Test
    public  void updateUser(){
            SqlSession sqlSession = MybatisUtils.getSqlSession();
            UserDao userDao = sqlSession.getMapper(UserDao.class);
        int update = userDao.updateUser(new User(4, "小小", "112"));
        if(update>0){
            System.out.println("更新成功");
        }
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public  void deleteUser(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserDao userDao = sqlSession.getMapper(UserDao.class);
        int i = userDao.deleteUser(4);
        if(i>0){
            System.out.println("删除成功");
        }
        sqlSession.commit();
        sqlSession.close();
    }
}

注意到：增删改操作必须提交事务！！！否则数据无法执行到数据库中！！