refactor(yudao-module-llm): 优化知识库文档处理逻辑

- 增加对 rateWordVO 和 words 列表的空值检查，避免空指针异常
- 在文档列表为空时，设置空的 wordList 和 groupId
- 优化 parseEmbeddingResponse 返回值处理，增加空值检查
- 添加对命中率结果的验证，避免无效值

yudao-module-llm/yudao-module-llm-biz/src/main/java/cn/iocoder/yudao/module/llm/service/conversation/ConversationServiceImpl.java

@@ -517,9 +517,16 @@ public class ConversationServiceImpl implements ConversationService {
             // 2. 遍历处理每个文档
             for (KnowledgeDocumentsDO document : documentList) {
                 ParagraphHitRateWordVO rateWordVO = processDocument(document, chatReqVO, knowledgeBase);
-                words.add(rateWordVO);
+                if (rateWordVO!=null){
+                    words.add(rateWordVO);
+                }
+            }
+            if (CollectionUtils.isEmpty(words)){
+                paragraphHitRateListVO.setWordList(Collections.emptyList());
+                paragraphHitRateListVO.setGroupId("");
+            }else {
+                paragraphHitRateListVO.setWordList(words);
             }
-            paragraphHitRateListVO.setWordList(words);
 
             // 请求结果添加到 Redis，查询段落命中率
             String redisKey = String.format("%s:%s", KNOWLEDGE_DOCUMENTS_REDIS_KEY, chatReqVO.getUuid());
@@ -567,7 +574,11 @@ public class ConversationServiceImpl implements ConversationService {
             log.info("[KnowledgeBase] 知识库请求结果:{}", response);
 
             paragraphHitRateListVO.setDocumentName(document.getDocumentName());
-            paragraphHitRateListVO.setParagraphHitRate(parseEmbeddingResponse(response, knowledgeBase, chatReqVO.getUuid()));
+            List<ParagraphHitRateVO> rateVOS = parseEmbeddingResponse(response, knowledgeBase, chatReqVO.getUuid());
+            if (CollectionUtils.isNotEmpty(rateVOS)){
+                return null;
+            }
+            paragraphHitRateListVO.setParagraphHitRate(rateVOS);
         } catch (Exception e) {
             log.warn("{} 文档[{}]处理异常: {}", "[KnowledgeBase]", document.getId(), e.getMessage());
             // 单个文档失败不影响整体流程
@@ -616,6 +627,10 @@ public class ConversationServiceImpl implements ConversationService {
             String rateResult = df.format(rate);
             log.info("{} 命中率: {}", "[KnowledgeBase]", rateResult);
 
+            if (StringUtils.isBlank(rateResult)||Double.parseDouble(rateResult)<=0.0){
+                return Collections.emptyList();
+            }
+
             if (StringUtils.isNotBlank(pageContent)) {
                 knowledgeBase.append("\n[知识库内容] ").append(pageContent);
                 log.info("{} 添加知识内容，长度: {}", "[KnowledgeBase]", pageContent.length());