优化相关问答

src/main/java/cn/meteor/beyondclouds/modules/question/mapper/QuestionTagMapper.java

@@ -2,6 +2,11 @@ package cn.meteor.beyondclouds.modules.question.mapper;
 
 import cn.meteor.beyondclouds.modules.question.entity.QuestionTag;
 import com.baomidou.mybatisplus.core.mapper.BaseMapper;
+import com.baomidou.mybatisplus.core.metadata.IPage;
+import org.apache.ibatis.annotations.Param;
+import org.apache.ibatis.annotations.Select;
+
+import java.util.List;
 
 /**
  * <p>
@@ -13,4 +18,11 @@ import com.baomidou.mybatisplus.core.mapper.BaseMapper;
  */
 public interface QuestionTagMapper extends BaseMapper<QuestionTag> {
 
+    /**
+     * 通过标签ID集合获取相关的问题ID
+     * @param page 分页
+     * @param tagIds 标签ID集合
+     * @return 问题ID的分页信息
+     */
+    IPage<String> relevantQuestionIdPage(IPage<String> page, @Param("tagIds") List<String> tagIds);
 }

src/main/java/cn/meteor/beyondclouds/modules/question/mapper/xml/QuestionTagMapper.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="cn.meteor.beyondclouds.modules.question.mapper.QuestionTagMapper">
-
+    <select id="relevantQuestionIdPage" resultType="String">
+        select
+        DISTINCT(question_id)
+        from (
+        select
+        *
+        from question_tag
+        where tag_id in
+        <foreach collection="tagIds" item="tagId" index="index" open="(" close=")" separator=",">
+            #{tagId}
+        </foreach>
+        ) qt
+    </select>
 </mapper>

src/main/java/cn/meteor/beyondclouds/modules/question/service/IQuestionTagService.java

@@ -31,8 +31,9 @@ public interface IQuestionTagService extends IService<QuestionTag> {
 
     /**
      * 根据标签ID集合查询相关问题
+     * @param page 分页信息
      * @param tagIds 标签ID集合
-     * @return 相关问题ID
+     * @return 相关问题ID分页
      */
-    List<String> getQuestionsByTagIds(List<String> tagIds);
+    IPage<String> getQuestionsByTagIds(IPage<String> page, List<String> tagIds);
 }

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

@@ -427,26 +427,34 @@ public class QuestionServiceImpl extends ServiceImpl<QuestionMapper, Question> i
             throw new QuestionServiceException(QuestionErrorCode.QUESTION_NOT_FOUND);
         }
 
-        IPage<Question> page = new Page<>(pageNumber, pageSize);
+        IPage<String> tagIdsPage = new Page<>(pageNumber, pageSize);
+        IPage<Question> questionPage = new Page<>(pageNumber, pageSize);
 
         //2.得到问题对应的tagIds
         List<String> tagIds = questionTagService.list(QuestionUtils.getWrapper("question_id", question.getQuestionId()))
                                                 .stream().map(QuestionTag::getTagId).collect(Collectors.toList());
 
-        //如果问题引用标签不为空，则通过tagIds得到相关问答，否则，直接返回page
+        //3.判断tagIds是否为空
         if (!CollectionUtils.isEmpty(tagIds)) {
-            //得到相关问答的问题ID
-            List<String> questionIds = questionTagService.getQuestionsByTagIds(tagIds);
+            questionTagService.getQuestionsByTagIds(tagIdsPage, tagIds);
 
-            //通过问题ID得到问题的具体信息
-            QueryWrapper<Question> questionQueryWrapper = new QueryWrapper<>();
-            questionQueryWrapper.in("q.question_id", questionIds)
-                                .orderByDesc("q.create_time");
+            questionPage.setTotal(tagIdsPage.getTotal());
+            questionPage.setCurrent(tagIdsPage.getCurrent());
 
-            return questionMapper.selectPageWithTags(page, questionQueryWrapper);
+            List<String> questionIds = tagIdsPage.getRecords();
+
+            //判断questionIds的长度是否为1，若为1，则说明questionIds只有传入的questionId，直接返回空
+            if (questionIds.size() != 1) {
+                //移除自身ID
+                questionIds.remove(question.getQuestionId());
+                questionPage.setRecords(questionMapper.listByIdsWithTags(questionIds));
             }else {
-            return page;
+                questionPage.setRecords(List.of());
             }
-
+        }else {
+            questionPage.setRecords(List.of());
         }
+        return questionPage;
+    }
+
 }

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

@@ -41,10 +41,13 @@ public class QuestionTagServiceImpl extends ServiceImpl<QuestionTagMapper, Quest
 
     private QuestionMapper questionMapper;
 
+    private QuestionTagMapper questionTagMapper;
+
     @Autowired
-    public QuestionTagServiceImpl(ITagService tagService, QuestionMapper questionMapper) {
+    public QuestionTagServiceImpl(ITagService tagService, QuestionMapper questionMapper, QuestionTagMapper questionTagMapper) {
         this.tagService = tagService;
         this.questionMapper = questionMapper;
+        this.questionTagMapper = questionTagMapper;
     }
 
     @Autowired
@@ -78,9 +81,7 @@ public class QuestionTagServiceImpl extends ServiceImpl<QuestionTagMapper, Quest
     }
 
     @Override
-    public List<String> getQuestionsByTagIds(List<String> tagIds) {
-        QueryWrapper<QuestionTag> questionTagQueryWrapper = new QueryWrapper<>();
-        questionTagQueryWrapper.in("tag_id", tagIds);
-        return list(questionTagQueryWrapper).stream().map(QuestionTag::getQuestionId).collect(Collectors.toList());
+    public IPage<String> getQuestionsByTagIds(IPage<String> page, List<String> tagIds) {
+        return questionTagMapper.relevantQuestionIdPage(page, tagIds);
     }
 }