Merge remote-tracking branch 'origin/fix-issue#29'

# Conflicts:
#	src/main/java/cn/meteor/beyondclouds/modules/question/api/QuestionApi.java
#	src/main/java/cn/meteor/beyondclouds/modules/question/service/IQuestionService.java
#	src/main/java/cn/meteor/beyondclouds/modules/question/service/impl/QuestionServiceImpl.java

src/main/java/cn/meteor/beyondclouds/modules/question/api/QuestionApi.java

@@ -269,4 +269,17 @@ public class QuestionApi {
         }
     }
 
+    @Anonymous
+    @ApiOperation("得到标签下的问答列表")
+    @GetMapping("/tag/{tagId}/questions")
+    public Response<PageVO<Question>> getQuestionsByTagId(@Valid PageForm pageForm, @PathVariable("tagId") String tagId) {
+        try {
+            IPage<Question> page = questionService.getQuestionsByTagId(pageForm.getPage(), pageForm.getSize(), tagId);
+            PageVO<Question> pageVO = new PageVO<>(page);
+            return Response.success(pageVO);
+        } catch (QuestionTagServiceException e) {
+            e.printStackTrace();
+            return Response.error(e);
+        }
+    }
 }

src/main/java/cn/meteor/beyondclouds/modules/question/enums/QuestionTagErrorCode.java

@@ -7,7 +7,10 @@ import cn.meteor.beyondclouds.core.IErrorCode;
  * @since 2020/2/1
  */
 public enum QuestionTagErrorCode implements IErrorCode {
-    ;
+    /**
+     * 标签不存在
+     */
+    TAG_NOT_FOUND(6001, "标签不存在");
 
     private long code;
     private String msg;

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

@@ -103,5 +103,14 @@ public interface IQuestionService extends IService<Question> {
      */
     IPage<Question> questionRecommends(Integer pageNumber, Integer pageSize, String questionId) throws QuestionServiceException;
 
+    /**
+     * 得到标签下的问答列表
+     * @param pageNumber 页数
+     * @param pageSize 页面大小
+     * @param tagId 标签ID
+     * @return 分页对象
+     * @throws QuestionTagServiceException 问题标签业务异常
+     */
+    IPage<Question> getQuestionsByTagId(Integer pageNumber, Integer pageSize, String tagId) throws QuestionTagServiceException;
 
 }

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

@@ -3,6 +3,7 @@ package cn.meteor.beyondclouds.modules.question.service.impl;
 import cn.meteor.beyondclouds.modules.question.bean.QuestionDetails;
 import cn.meteor.beyondclouds.modules.question.entity.*;
 import cn.meteor.beyondclouds.modules.question.enums.QuestionErrorCode;
+import cn.meteor.beyondclouds.modules.question.enums.QuestionTagErrorCode;
 import cn.meteor.beyondclouds.modules.question.exception.QuestionServiceException;
 import cn.meteor.beyondclouds.modules.question.exception.QuestionTagServiceException;
 import cn.meteor.beyondclouds.modules.question.mapper.QuestionMapper;
@@ -32,7 +33,6 @@ import org.springframework.util.StringUtils;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.stream.Collectors;
-import java.util.stream.Stream;
 
 /**
  * <p>
@@ -432,7 +432,7 @@ public class QuestionServiceImpl extends ServiceImpl<QuestionMapper, Question> i
 
         //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());
+                .stream().map(QuestionTag::getTagId).collect(Collectors.toList());
 
         //3.判断tagIds是否为空
         if (!CollectionUtils.isEmpty(tagIds)) {
@@ -457,4 +457,33 @@ public class QuestionServiceImpl extends ServiceImpl<QuestionMapper, Question> i
         return questionPage;
     }
 
+    @Override
+    public IPage<Question> getQuestionsByTagId(Integer pageNumber, Integer pageSize, String tagId) throws QuestionTagServiceException {
+        //1.检查标签是否存在
+        Tag tag = tagService.getById(tagId);
+        if (null == tag) {
+            throw new QuestionTagServiceException(QuestionTagErrorCode.TAG_NOT_FOUND);
+        }
+
+        IPage<Question> questionPage = new Page<>(pageNumber, pageSize);
+        IPage<QuestionTag> questionTagPage = new Page<>(pageNumber, pageSize);
+
+        //2.通过标签ID得到对应的问题ID
+        QueryWrapper<QuestionTag> questionTagQueryWrapper = new QueryWrapper<>();
+        questionTagQueryWrapper.eq("tag_id", tag.getTagId());
+
+        questionTagService.page(questionTagPage,questionTagQueryWrapper);
+
+        List<String> questionIds = questionTagPage.getRecords().stream().map(QuestionTag::getQuestionId).collect(Collectors.toList());
+
+        questionPage.setTotal(questionTagPage.getTotal());
+        questionPage.setCurrent(questionTagPage.getCurrent());
+
+        if (!CollectionUtils.isEmpty(questionIds)) {
+            questionPage.setRecords(questionMapper.listByIdsWithTags(questionIds));
+        }else {
+            questionPage.setRecords(List.of());
+        }
+        return questionPage;
+    }
 }