src/main/resources/mapper/xml/FriendsListMapper.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.pt5.pthouduan.mapper.FriendsListMapper">

    <!-- 插入好友申请 -->
    <insert id="insertFriendRequest" parameterType="com.pt5.pthouduan.entity.FriendsList">
        INSERT INTO friendslist (relationid, friend1, friend2, requestTime, status)
        VALUES (#{relationid}, #{friend1}, #{friend2}, #{requestTime}, #{status})
    </insert>

    <!-- 同意好友申请（更新 status） -->
    <update id="updateFriendStatus">
        UPDATE friendslist
        SET status = #{status}
        WHERE (friend1 = #{friend1} AND friend2 = #{friend2})
           OR (friend1 = #{friend2} AND friend2 = #{friend1})
    </update>

    <!-- 删除好友关系（不区分 friend1 和 friend2） -->
    <delete id="deleteByFriendPair">
        DELETE FROM friendslist
        WHERE (friend1 = #{friend1} AND friend2 = #{friend2})
           OR (friend1 = #{friend2} AND friend2 = #{friend1})
    </delete>

    <!-- 查询某用户所有已通过好友 -->
    <select id="selectAcceptedFriends" parameterType="long" resultType="com.pt5.pthouduan.entity.FriendsList">
        SELECT * FROM friendslist
        WHERE (friend1 = #{userid} OR friend2 = #{userid})
          AND status = 'accepted'
    </select>

    <!-- 查询自己收到的好友请求（自己是 friend2 且 status = 'pending'） -->
    <select id="selectPendingRequests" parameterType="long" resultType="com.pt5.pthouduan.entity.FriendsList">
        SELECT * FROM friendslist
        WHERE friend2 = #{userid}
          AND status = 'pending'
        ORDER BY requestTime DESC
    </select>

</mapper>