mybatis foerach多条件查询

偏执的太偏执、 2022-04-25 06:38 488阅读 0赞

比如,我们要查找很多id的user1,31…  
解释下foreach中各个参数意思:

*  **foreach元素的属性主要有 item，index，collection，open，separator，close。**

1.  item表示集合中每一个元素进行迭代时的别名，
2.  index指 定一个名字，用于表示在迭代过程中，每次迭代到的位置，
3.  open表示该语句以什么开始，
4.  separator表示在每次进行迭代之间以什么符号作为分隔 符，
5.  close表示以什么结束。  
    UserMapper.xml

<select id="findUserByMoreId"  parameterType="list" resultType="com.company.User">
            select id,name,password from user where  id in
            <foreach collection="list" item="item" separator="," open="(" close=")" index="index">
                #{item}
            </foreach>
        </select>

照着写就行,需要修改自己参数.  
**测试类:**

@Test
        public void findUserByMoreId () throws IOException {
            InputStream is = Resources.getResourceAsStream("SqlMapConfig.xml");
            //建立会话工厂
            SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
            SqlSession sqlSession = sqlSessionFactory.openSession();
            UserMapper mapper = sqlSession.getMapper(UserMapper.class);
            List<Integer> list= Arrays.asList(1,31);
            List<User> userList=mapper.findUserByMoreId(list);
            System.out.println(userList);
            sqlSession.close();
    
        }

**接口mapper:**

List<User> findUserByMoreId (List<Integer> list);

**结果显示:**

2019-05-30 08:59:48,726 [main] DEBUG [com.mapper.UserMapper] - Cache Hit Ratio [com.mapper.UserMapper]: 0.0
    2019-05-30 08:59:49,549 [main] DEBUG [com.mapper.UserMapper.findUserByMoreId] - ==>  Preparing: select id,name,password from user where id in ( ? , ? ) 
    2019-05-30 08:59:49,675 [main] DEBUG [com.mapper.UserMapper.findUserByMoreId] - ==> Parameters: 1(Integer), 31(Integer)
    2019-05-30 08:59:49,744 [main] DEBUG [com.mapper.UserMapper.findUserByMoreId] - <==      Total: 2
    [User{id=1, name='帅帅', password='帅帅', aClass=null, listTea=null}
    , User{id=31, name='jok1', password='jok1', aClass=null, listTea=null}
    ]

**希望对大家有帮助!!!**