Mybatis注解实现CURD

1.编写接口

package com.zzqsmile.dao;

import com.zzqsmile.pojo.User;
import org.apache.ibatis.annotations.*;

import java.util.List;

public interface UserMapper {
    @Select("select * from mybatis.user")
    List<User> getUsers();

    //方法存在多个参数，所有的参数前必须要加@Param()
    @Select("select * from mybatis.user where id =#{id}")
    User getUserById(@Param("id") int id);

    //增加用户
    @Insert("insert into mybatis.user (id,name,pwd) values(#{id},#{name},#{pwd})")
    int userAdd(User user);

    //修改用户
    @Update("update mybatis.user set name = #{name},pwd = #{pwd} where id = #{id}")
    int userUpd(User user);

    //删除用户
    @Delete("delete from mybatis.user where id = #{uid}")
    int userDel(@Param("uid")int id);
}

2.绑定接口

    <!--    绑定接口-->
    <mappers>
        <mapper class="com.zzqsmile.dao.UserMapper"></mapper>
    </mappers>

3.编写测试类

package com.zzqsmile.dao;

import com.zzqsmile.pojo.User;
import com.zzqsmile.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class UserMapperTest {

    @Test
    public void test(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        List<User> users = mapper.getUsers();
        for (User user : users) {
            System.out.println(user);
        }

        sqlSession.close();
    }

    @Test
    public void getUserById(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        User userById = mapper.getUserById(1);

        System.out.println(userById);

    }

    @Test
    public void userAdd(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        int i = mapper.userAdd(new User(6,"张三丰","123321"));

        if (i>0){
            System.out.println("添加成功");
        }
    }

    @Test
    public void userUpd(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        int i = mapper.userUpd(new User(6,"张三丰","999999"));

        if (i>0){
            System.out.println("修改成功");
        }
    }

    @Test
    public void userDel(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        int i = mapper.userDel(5);

        if (i>0){
            System.out.println("删除成功");
        }
    }

}

@Param()注意点

• 基本类型或String类型要加上
• 引用类型不需要加
• 如果只有1个基本类型可以省略，但是建议添加