发布话题不可重复

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

@@ -42,8 +42,13 @@ public class TopicApi {
     @PostMapping("/topic")
     public Response createTopic(@RequestBody @Valid CreateTopicForm createTopicForm, @CurrentSubject Subject subject) {
 
-        TopicDetail topic = topicService.createTopic(String.valueOf(subject.getId()), createTopicForm.getTopicName());
-        return Response.success(topic);
+        try {
+            TopicDetail topic = topicService.createTopic(String.valueOf(subject.getId()), createTopicForm.getTopicName());
+            return Response.success(topic);
+        } catch (TopicServiceException e) {
+            e.printStackTrace();
+            return Response.error(e);
+        }
 
     }
 

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

@@ -25,7 +25,7 @@ public interface ITopicService extends IService<Topic> {
      * @param topicName
      * @return TopicDetail
      */
-    TopicDetail createTopic(String userId, String topicName);
+    TopicDetail createTopic(String userId, String topicName) throws TopicServiceException;
 
     /**
      * 检索话题

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

@@ -53,15 +53,22 @@ public class TopicServiceImpl extends ServiceImpl<TopicMapper, Topic> implements
     }
 
     @Override
-    public TopicDetail createTopic(String userId, String topicName) {
+    public TopicDetail createTopic(String userId, String topicName) throws TopicServiceException{
 
-        //1. 创建话题
+        //1. 检测是否存在该话题
+        QueryWrapper<Topic> topicQueryWrapper = new QueryWrapper<>();
+        topicQueryWrapper.eq("topic_name",topicName);
+        if(getOne(topicQueryWrapper) != null) {
+            throw new TopicServiceException(TopicErrorCode.TOPIC_EXISTS);
+        }
+
+        //2. 创建话题
         Topic topic = new Topic();
         topic.setUserId(userId);
         topic.setTopicName(topicName);
         save(topic);
 
-        //2. 返回话题的id与话题名称
+        //3. 返回话题的id与话题名称
         TopicDetail topicDetail=new TopicDetail();
         BeanUtils.copyProperties(topic, topicDetail);
         return topicDetail;