提高listByIds时代码的稳定性

src/main/java/cn/meteor/beyondclouds/modules/question/service/impl/QuestionTagServiceImpl.java

@@ -13,6 +13,7 @@ import cn.meteor.beyondclouds.modules.tag.service.ITagService;
 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.HashSet;
 import java.util.Iterator;
@@ -77,10 +78,10 @@ public class QuestionTagServiceImpl extends ServiceImpl<QuestionTagMapper, Quest
                 .collect(Collectors.toList());
 
         // 3.根据tagIds查询出标签并返回
-        if (tagIds.size() > 0) {
-            return tagService.listByIds(tagIds);
+        if (CollectionUtils.isEmpty(tagIds)) {
+            return List.of();
         } else {
-            return null;
+            return tagService.listByIds(tagIds);
         }
     }
 }

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

@@ -15,6 +15,7 @@ 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;
@@ -112,7 +113,12 @@ public class TopicServiceImpl extends ServiceImpl<TopicMapper, Topic> implements
                 .collect(Collectors.toList());
 
         // 3. 通过用户id批量查询用户
-        List<Topic> topics = listByIds(topicIds);
+        List<Topic> topics;
+        if (CollectionUtils.isEmpty(topicIds)) {
+            topics = List.of();
+        } else {
+            topics = listByIds(topicIds);
+        }
 
         // 5.构造分页结果
         IPage<Topic> userPage = new Page<>();
@@ -143,7 +149,12 @@ 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 = userService.listByIds(followerIds);
+        List<User> followers;
+        if (CollectionUtils.isEmpty(followerIds)) {
+            followers = List.of();
+        } else {
+            followers = userService.listByIds(followerIds);
+        }
 
         // 4.去除敏感信息
         followers.stream()