Java教程
【Java+MySql】好友关系数据库设计及Java代码实战
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业务需求：A、B两个用户的关注/取消关注接口
1、建表
由数据库设计文档和数据库存放关系可知，
数据 用户的userId 既可以在数据库的user_id位置，也可以在数据库的follower_id位置上。
2、该接口的实现思路如下
2.1、关注/取消关注 用户的设计思路
参数：用户A、用户B、关注/取消关注flag
A和B的关系，假设A在数据库的A位置
00 A关注B
01 B关注A
02 A、B相互关注
备注：A在数据库的B位置时，如上关系为01、00、02
2.2、实现思路如下：
0.去数据库查询A、B这两个用户有没有关系(00/01/02)
1.点击关注 --说明A和B的关系：1>没有关系；2>B关注A
1-1.判断A和B的关系
1-2.如果没有关系，则添加一条数据
1-3.如果有关系，则将关系改为相互关注(这个要结合实际，如果A已经关注了B，则A不能在关注B了，即进来
的肯定是B点击了关注A)
2.3、点击取消关注 --说明A和B的关系：
1>A关注B；2>A、B相互关注
2.4、判断A和B的关系
2.4.1.如果是关注(结合实际，只有相互关注和关注两种关系)，则取消关注，即删除这条数据
2.4.2.如果是相互关注，则需要判断A和B的位置
2.4.3 如果A在数据库的A位置，则修改A和B的关系为被关注--即关系为01
2.4.4 如果A在数据库的B位置，则修改A和B的关系为被关注--即关系为00
3、Java代码实现
/**
* 添加用户关注(关注、取消关注)
* @param json
* @return
*/
@PostMapping("/addUserRelationShip")
public Map<String,Object> addUserRelationShip(@RequestBody String json) {
Map<String, Object> resultMap = new HashMap<>();
UserRelationShip relationShip = JSON.parseObject(json, UserRelationShip.class);
relationShip.setRelationId(UUID.randomUUID().toString().replace("-", ""));
System.out.println(relationShip);
JSONObject jsonObject = JSONObject.parseObject(json);
Integer status = jsonObject.getInteger("status");
String userId = jsonObject.getString("userId");
String followerId = jsonObject.getString("followerId");
//获取A和B的关系
List<UserRelationShip> userRelationShips = relationShipService.checkRelation(userId,followerId);
if (userRelationShips.size() > 0 ) { //已经有关系了
System.out.println("有关系了");
UserRelationShip userRelationShip = userRelationShips.get(0);
System.out.println(userRelationShip.getRelation());
String relation = userRelationShip.getRelation();
String relationUserId = userRelationShip.getUserId();
String relationFollowerId = userRelationShip.getFollowerId();
String position = "";
if (userId.equals(relationUserId)) {
position = "left";
} else if (userId.equals(relationFollowerId)) {
position = "right";
}
if (status == 1) { //执行关注操作
if (position.equals("left")) {
if (relation.equals("00") || relation.equals("02")) { //自己在左边：00:主动关注过对方，02：两人互关着呢，不能再执行关注操作了
resultMap.put("message", "关注失败，不能重复关注");
resultMap.put("state", JsonResult.failing);
} else {//对方在关注你，但是你没有关注对方，所有执行操作，更改状态为02，变成互关的状态
int updateCount = relationShipService.updateRelationStatus(userId,followerId,"02");
if (updateCount > 0) {
resultMap.put("message", "关注成功");
resultMap.put("state", JsonResult.SUCCESS);
} else {
resultMap.put("message", "关注失败");
resultMap.put("state", JsonResult.failing);
}
}
} else { //说明自己在右边，关注是自己被对方主动关注过，
if (relation.equals("01") || relation.equals("02")) { //自己在右边：01：自己关注别人了，02：两人互关呢，不能再执行关注操作了
resultMap.put("message", "关注失败，不能重复关注");
resultMap.put("state", JsonResult.failing);
} else { //00:对方在关注你，但是你没有关注对方，所有执行操作，更改状态为02，变成互关的状态
int updateCount = relationShipService.updateRelationStatus(userId,followerId,"02");
if (updateCount > 0) {
resultMap.put("message", "关注成功");
resultMap.put("state", JsonResult.SUCCESS);
} else {
resultMap.put("message", "关注失败");
resultMap.put("state", JsonResult.failing);
}
}
}
} else {//执行取关操作
if (position.equals("left")) {
if (relation.equals("00")) { //此时只有自己关注了对方，但是对方，却没有关注自己，所以执行取消操作的话，直接删除就行了
int deleteCount = relationShipService.deleteUserRelationShip(userId,followerId);
if (deleteCount > 0) {
resultMap.put("message", "取消关注成功");
resultMap.put("state", JsonResult.SUCCESS);
} else {
resultMap.put("message", "取消关注失败");
resultMap.put("state", JsonResult.failing);
}
} else if (relation.equals("02")) { //两人互关呢，自己执行取关操作，要更改状态为01
int updateCount = relationShipService.updateRelationStatus(userId,followerId,"01");
if (updateCount > 0) {
resultMap.put("message", "取消关注成功");
resultMap.put("state", JsonResult.SUCCESS);
} else {
resultMap.put("message", "取消关注失败");
resultMap.put("state", JsonResult.failing);
}
} else { //01时候，对方在关注者自己，就没关注别人，取关个毛线啊
resultMap.put("message", "取消关注失败");
resultMap.put("state", JsonResult.failing);
}
} else { //说明自己在右边，关注是自己被对方主动关注过，
if (relation.equals("01")) { //自己关注了对方，但是对方却没有关注自己，直接删除就行了
int deleteCount = relationShipService.deleteUserRelationShip(userId,followerId);
if (deleteCount > 0) {
resultMap.put("message", "取消关注成功");
resultMap.put("state", JsonResult.SUCCESS);
} else {
resultMap.put("message", "取消关注失败");
resultMap.put("state", JsonResult.failing);
}
} else if (relation.equals("02")) {
int updateCount = relationShipService.updateRelationStatus(userId,followerId,"00");
if (updateCount > 0) {
resultMap.put("message", "取消关注成功");
resultMap.put("state", JsonResult.SUCCESS);
} else {
resultMap.put("message", "取消关注失败");
resultMap.put("state", JsonResult.failing);
}
} else { //你都没关注别人，取关个毛线啊
resultMap.put("message", "取消关注失败");
resultMap.put("state", JsonResult.failing);
}
}
}
} else { //没有关系
System.out.println("没有关系");
relationShip.setRelation("00"); //既然没有关系，就新增一条，记录状态标记为00
int addCount = relationShipService.addUserRelationShip(relationShip);
if (addCount > 0) {
System.out.println("新增关系成功");
resultMap.put("message", "新增关注成功");
resultMap.put("state", JsonResult.SUCCESS);
} else {
resultMap.put("message", "新增关注失败");
resultMap.put("state", JsonResult.failing);
}
}
return resultMap;
}
备注：上述的sql语句：addUserRelationShip / deleteUserRelationShip / updateRelationStatus
<!-- 检查好友关系 -->
<select id="checkRelation" resultMap="BasePlusResultMap">
select * from follower where (user_id = #{userId} and follower_id = #{followerId}) or (user_id = #{followerId} and follower_id = #{userId})
</select>
<!-- 关注某人 -->
<insert id="addUserRelationShip" >
insert into follower(relation_id,user_id,follower_id,status,relation) values (#{relationId},#{userId},#{followerId},#{status},#{relation})
</insert>
<!-- 取消关注某人 -->
<delete id="deleteUserRelationShip">
delete from follower where user_id=#{userId} and follower_id = #{followerId}
</delete>
<!-- 更新还有关系状态 -->
<update id="updateRelationStatus">
update follower set relation = #{relation} where (user_id = #{userId} and follower_id = #{followerId}) or (user_id = #{followerId} and follower_id = #{userId})
</update>
封装检查好友关系的逻辑代码，可以贴过去直接用的
public static int checkRelationStatus(String userId,String targetId,List<Fans> userRelationShips) {
int relationStatus = 0;
for (int index = 0;index < userRelationShips.size();index++) {
Fans userRelationShip = userRelationShips.get(index);
String relationShipUserId = userRelationShip.getUserId();
String relationShipFollowerId = userRelationShip.getFollowerId();
String relation = userRelationShip.getRelation();
if (relationShipUserId.equals(userId) && relationShipFollowerId.equals(targetId) || (relationShipUserId.equals(targetId) && relationShipFollowerId.equals(userId))) {
String position = "";
if (userId.equals(relationShipUserId)) {
position = "left";
} else if (userId.equals(relationShipFollowerId)) {
position = "right";
}
if (position.equals("left")) {
if (relation.equals("00") || relation.equals("02")) { //自己在左边：00:主动关注过对方，02：两人互关着呢，不能再执行关注操作了
relationStatus = 1;
}
} else { //说明自己在右边，关注是自己被对方主动关注过，
if (relation.equals("01") || relation.equals("02")) { //自己在右边：01：自己关注别人了，02：两人互关呢，不能再执行关注操作了
relationStatus = 1;
}
}
break;
}
}
return relationStatus;
}
4、获取我的关注列表
/* *//**
* 获取我的关注列表
* @param userId
* @param page
* @param pageSize
* @return
*/
@GetMapping("/selectUserAttention")
public Map<String,Object> selectUserAttention(String userId,int page,int pageSize){
Map<String,Object> resultMap = new HashMap<>();
List<RelationShipUser> relationUsers = new ArrayList<>();
Map<String,Object> paramMap = new HashMap<>();
paramMap.put("userId",userId);
paramMap.put("followerId",userId);
int pageCount = (page)* pageSize;
paramMap.put("page", pageCount);
paramMap.put("size",pageSize);
List<Fans> userRelationShips = fansUserService.selectUserAttention(paramMap);
if(userRelationShips.size() > 0) {
List<String> userIds = new ArrayList<>();
for (int index = 0;index < userRelationShips.size();index++) {
Fans userRelationShip = userRelationShips.get(index);
String relationShipUserId = userRelationShip.getUserId();
String relationShipFollowerId = userRelationShip.getFollowerId();
if (relationShipFollowerId.equals(userId)) {
userIds.add(relationShipUserId);
} else {
userIds.add(relationShipFollowerId);
}
}
System.out.println(userIds);
//获取用户
List<UserClone> users = relationShipService.queryUserWithIds(userIds);
if (users.size() > 0) {
for (int index = 0;index < users.size(); index++) {
RelationShipUser relationShipUser = new RelationShipUser();
relationShipUser.setUser(users.get(index));
relationUsers.add(relationShipUser);
}
}
for (int idx = 0;idx < relationUsers.size();idx++) {
RelationShipUser relationShipUser = relationUsers.get(idx);
String targetId = relationShipUser.getUser().getUserId();
int relationStatus = checkRelationStatus(userId,targetId,userRelationShips);
relationShipUser.setStatus(relationStatus);
relationUsers.set(idx,relationShipUser);
}
resultMap.put("data",relationUsers);
resultMap.put("message", "查询关注人成功");
resultMap.put("state", JsonResult.SUCCESS);
}else if(userRelationShips.size() == 0){
resultMap.put("data",relationUsers);
resultMap.put("message", "你还没关注任何人");
resultMap.put("state", JsonResult.SUCCESS);
}else {
resultMap.put("message", "查询关注人失败");
resultMap.put("state", JsonResult.failing);
}
return resultMap;
}
以上代码所用的Sql语句：selectUserAttention
<!--我的关注-->
<select id="selectUserAttention" parameterType="Map" resultMap="BasePlusResultMap">
select * from follower where (follower.user_id = #{userId} and follower.relation in ('00','02')) or
(follower.follower_id = #{followerId} and follower.relation in ('01','02'))
LIMIT #{page}, #{size}
</select>
5、获取我的粉丝
/**
* 获取我的粉丝列表
* @param userId
* @param page
* @param pageSize
* @return
*/
@GetMapping("/selectUserVermicelli")
public Map<String,Object> selectUserVermicelli(String userId,int page,int pageSize){
Map<String,Object> resultMap = new HashMap<>();
List<RelationShipUser> relationUsers = new ArrayList<>();
Map<String,Object> paramMap = new HashMap<>();
paramMap.put("userId",userId);
paramMap.put("followerId",userId);
int pageCount = (page)* pageSize;
paramMap.put("page", pageCount);
paramMap.put("size",pageSize);
List<Fans> userRelationShips = fansUserService.selectUserVermicelli(paramMap);
if(userRelationShips.size() > 0){
List<String> userIds = new ArrayList<>();
for (int index = 0;index < userRelationShips.size();index++) {
Fans userRelationShip = userRelationShips.get(index);
String relationShipUserId = userRelationShip.getUserId();
String relationShipFollowerId = userRelationShip.getFollowerId();
if (relationShipFollowerId.equals(userId)) {
userIds.add(relationShipUserId);
} else {
userIds.add(relationShipFollowerId);
}
}
System.out.println(userIds);
//获取用户
List<UserClone> users = relationShipService.queryUserWithIds(userIds);
if (users.size() > 0) {
for (int index = 0;index < users.size(); index++) {
RelationShipUser relationShipUser = new RelationShipUser();
relationShipUser.setUser(users.get(index));
relationUsers.add(relationShipUser);
}
}
for (int idx = 0;idx < relationUsers.size();idx++) {
RelationShipUser relationShipUser = relationUsers.get(idx);
String targetId = relationShipUser.getUser().getUserId();
int relationStatus = checkRelationStatus(userId,targetId,userRelationShips);
relationShipUser.setStatus(relationStatus);
relationUsers.set(idx,relationShipUser);
}
resultMap.put("data",relationUsers);
resultMap.put("message", "查询成功");
resultMap.put("state", JsonResult.SUCCESS);
}else if(userRelationShips.size() == 0){
resultMap.put("data",relationUsers);
resultMap.put("message", "");
resultMap.put("state", JsonResult.SUCCESS);
}else {
resultMap.put("message", "查询失败");
resultMap.put("state", JsonResult.failing);
}
return resultMap;
}
以上代码所用到的Sql：selectUserVermicelli
<!-- <!–我的粉丝-->
<select id="selectUserVermicelli" resultMap="BasePlusResultMap" parameterType="Map">
select u2.nickname, u2.phone,u2.avatar,follower.follower_id ,follower.relation_id,u2.user_id,follower.relation,u2.description,follower.user_id
from follower
inner join dnx_app_user u1 on follower.follower_id = u1.user_id
inner join dnx_app_user u2 on follower.user_id = u2.user_id
where (follower.user_id = #{userId} and follower.relation in ('01','02')) or
(follower.follower_id = #{followerId} and follower.relation in ('00','02'))
LIMIT #{page}, #{size}
</select>
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