Mybatis映射文件动态SQL语句-02

foreach

UserMapper.xml

<?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.hao.mapper.UserMapper">

   <select id="findByCondition" parameterType="user" resultType="user">

       select * from user

       <where>

           <if test="id!=0">

               and id=#{id}

           </if>

           <if test="username!=null">

               and username=#{username}

           </if>

           <if test="password!=null">

               and password=#{password}

           </if>

       </where>

   </select>

    <select id="findByIds" parameterType="list" resultType="user">

        select * from user

        <where>

            <foreach collection="list" open="id in(" close=")" item="id" separator=",">

                #{id}

            </foreach>

        </where>

    </select>

</mapper>

测试

 @Test

    public void test1() throws IOException {

        InputStream stream = Resources.getResourceAsStream("SqlMapConfig.xml");

        SqlSession sqlSession = new SqlSessionFactoryBuilder().build(stream).openSession();

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

       List<Integer> ids=new ArrayList<>();

       ids.add(1);

       ids.add(2);

        List<User> byIds = mapper.findByIds(ids);

        System.out.println(byIds);

    }

观看打印的日志

-collection 表示要做foreach循环的对象
- item 表示集合中每一个元素或者该集合的对象,支持对象点属性的方式获取属性。
- index 表示循环的下标,从0开始
- open 表示以什么开始
- separator 表示每次进行迭代之间以什么符号作为分隔符
- close表示以什么结束

巴特西

Mybatis映射文件动态SQL语句-02

foreach

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