Mybatis将java中的List集合转换为视图

野性酷女 2024-03-31 16:00 87阅读 0赞

### user表中的数据 ###

![23c28f6583ee4574a1ba6f72818883b9.png][]

### java代码 ###

@Service
    public class IUserServiceImpl implements IUserService  {
    
        @Autowired
        private IUserMapper userMapper;
    
        //查找相同的用户
        @Override
        public void selectSameUser() {
            List<User> userListParam = new ArrayList<>();
            User user1 = new User();
            user1.setId("1");
            user1.setAccount("test1");
            userListParam.add(user1);
            User user2 = new User();
            user2.setId("2");
            user2.setAccount("test2");
            userListParam.add(user2);
            User user3 = new User();
            user3.setId("3");
            user3.setAccount("test3");
            userListParam.add(user3);
            List<User> userListResult = userMapper.selectSameUser(userListParam);
            System.out.println(userListResult.toString());
        }
    }

@Mapper
    public interface IUserMapper extends BaseMapper<User> {
        //查找相同的用户
        List<User> selectSameUser(List<User> userList);
    }

### XML代码（sql） ###

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="com.slj.user.dao.IUserMapper">
        <select id="selectSameUser" parameterType="java.util.List" resultType="com.slj.user.entity.User">
            select
            a.*
            from user a
            inner join(
                <foreach collection="list" item="item" index="index" separator="union">
                    select
                    '${item.id}' as id
                    ,'${item.account}' as account
                </foreach>
            )tmp on tmp.id = a.id
        </select>
    </mapper>

### Idea控制台打印查询结果 ###

![032e29726b6b43fd8f792f80d65d0fe5.png][]

[23c28f6583ee4574a1ba6f72818883b9.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/6bde079f868740f18bf6dac799e6942e.png
[032e29726b6b43fd8f792f80d65d0fe5.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/609a52d4082c45128a6fe8d8cc0f1553.png