新增删除话题关注的接口

src/main/java/cn/meteor/beyondclouds/modules/topic/api/TopicApi.java

@@ -142,4 +142,18 @@ public class TopicApi {
         return Response.success(topicPageVO);
     }
 
+
+    @ApiOperation("取消关注话题")
+    @DeleteMapping("/topic/{topicId}/follower")
+    public Response delTopicFollower(@PathVariable("topicId") String topicId, @CurrentSubject Subject subject) {
+        try {
+            topicService.delFollowTopic((String) subject.getId(), topicId);
+            return Response.success();
+        } catch (TopicServiceException e) {
+            e.printStackTrace();
+            return Response.error(e);
+        }
+
+    }
+
 }

src/main/java/cn/meteor/beyondclouds/modules/topic/enums/TopicErrorCode.java

@@ -13,7 +13,8 @@ public enum TopicErrorCode implements IErrorCode {
      */
     TOPIC_EXISTS(3001, "该话题已存在"),
     TOPIC_NOT_EXISTS(3002, "该话题不存在"),
-    AlREADY_FOLLOWED(3003, "已关注过该话题");
+    AlREADY_FOLLOWED(3003, "已关注过该话题"),
+    NOT_FOLLOWED(3004, "未关注过该话题");
 
     TopicErrorCode(long code, String msg) {
         this.code = code;

src/main/java/cn/meteor/beyondclouds/modules/topic/service/ITopicService.java

 package cn.meteor.beyondclouds.modules.topic.service;
 
+import cn.meteor.beyondclouds.modules.tag.exception.TagServiceException;
 import cn.meteor.beyondclouds.modules.topic.entity.Topic;
 import cn.meteor.beyondclouds.modules.topic.exception.TopicServiceException;
 import cn.meteor.beyondclouds.modules.user.entity.User;
@@ -87,4 +88,12 @@ public interface ITopicService extends IService<Topic> {
      * @param count
      */
     void increaseReferenceCount(String topicId, int count);
+
+    /**
+     * 取消关注话题
+     * @param userId
+     * @param topicId
+     * @throws TopicServiceException
+     */
+    void delFollowTopic(String userId, String topicId) throws TopicServiceException;
 }

src/main/java/cn/meteor/beyondclouds/modules/topic/service/impl/TopicServiceImpl.java

 package cn.meteor.beyondclouds.modules.topic.service.impl;
 
+import cn.meteor.beyondclouds.modules.tag.exception.TagServiceException;
 import cn.meteor.beyondclouds.modules.topic.entity.Topic;
 import cn.meteor.beyondclouds.modules.topic.entity.TopicFollow;
 import cn.meteor.beyondclouds.modules.topic.enums.TopicErrorCode;
@@ -15,7 +16,6 @@ import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
 import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
-import org.springframework.util.CollectionUtils;
 
 import java.util.List;
 import java.util.stream.Collectors;
@@ -109,7 +109,7 @@ public class TopicServiceImpl extends ServiceImpl<TopicMapper, Topic> implements
     @Override
     public IPage<Topic> getTopicsMyFollowed(Integer pageNumber, Integer pageSize, String userId) {
 
-        // 1. 通过用户id获取该话题所有关注着
+        // 1. 通过用户id获取关注的所有话题id
         // 设置分页信息
         IPage<TopicFollow> page = new Page<>(pageNumber, pageSize);
 
@@ -123,13 +123,8 @@ public class TopicServiceImpl extends ServiceImpl<TopicMapper, Topic> implements
                 .map(TopicFollow::getTopicId)
                 .collect(Collectors.toList());
 
-        // 3. 通过用户id批量查询用户
-        List<Topic> topics;
-        if (CollectionUtils.isEmpty(topicIds)) {
-            topics = List.of();
-        } else {
-            topics = listByIds(topicIds);
-        }
+        // 3. 通过话题id批量查询用户
+        List<Topic> topics = listByIds(topicIds);
 
         // 5.构造分页结果
         IPage<Topic> userPage = new Page<>();
@@ -160,12 +155,7 @@ public class TopicServiceImpl extends ServiceImpl<TopicMapper, Topic> implements
                 .collect(Collectors.toList());
 
         // 3. 通过用户id批量查询用户
-        List<User> followers;
-        if (CollectionUtils.isEmpty(followerIds)) {
-            followers = List.of();
-        } else {
-            followers = userService.listByIds(followerIds);
-        }
+        List<User> followers = userService.listByIds(followerIds);
 
         // 4.去除敏感信息
         followers.stream()
@@ -212,4 +202,29 @@ public class TopicServiceImpl extends ServiceImpl<TopicMapper, Topic> implements
         }
     }
 
+    @Override
+    public void delFollowTopic(String userId, String topicId) throws TopicServiceException {
+
+        //1. 获取话题
+        Topic topic = getById(topicId);
+
+        //2. 找不到该话题，抛出业务异常
+        if (topic == null) {
+            throw new TopicServiceException(TopicErrorCode.TOPIC_NOT_EXISTS);
+        }
+
+        //3. 判断用户是否关注该话题
+        QueryWrapper<TopicFollow> delTopicFollowQueryWrapper = new QueryWrapper<>();
+        delTopicFollowQueryWrapper.eq("user_id", userId);
+        delTopicFollowQueryWrapper.eq("topic_id", topicId);
+
+        if (null == topicFollowService.getOne(delTopicFollowQueryWrapper)) {
+            throw new TopicServiceException(TopicErrorCode.NOT_FOLLOWED);
+        }
+
+        //4. 取消关注话题
+        topicFollowService.remove(delTopicFollowQueryWrapper);
+
+    }
+
 }