feat(knowledge-base): 添加知识库统计功能

- 后端服务新增 KnowledgeBaseStatisticsResp 和 RagFileStatistics 数据传输对象
- 在 KnowledgeBaseService 中实现 getStatistics 方法提供统计信息查询
- 为 RagFileRepository 添加 getStatistics 接口及其实现
- 通过 MyBatis Mapper 实现数据库层面的统计查询功能
- 在 KnowledgeBaseController 中暴露 /statistics 接口供前端调用
- 前端页面集成统计卡片组件展示知识库、文件数量及总大小信息
- 实现前后端数据同步机制确保统计数据实时更新

backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/application/KnowledgeBaseService.java

@@ -140,6 +140,18 @@ public class KnowledgeBaseService {
         return PagedResponse.of(respList, page.getCurrent(), page.getTotal(), page.getPages());
     }
 
+    public KnowledgeBaseStatisticsResp getStatistics() {
+        KnowledgeBaseStatisticsResp resp = new KnowledgeBaseStatisticsResp();
+        resp.setTotalKnowledgeBases(knowledgeBaseRepository.count());
+
+        RagFileStatistics fileStatistics = ragFileRepository.getStatistics();
+        if (fileStatistics != null) {
+            resp.setTotalFiles(fileStatistics.getTotalFiles() != null ? fileStatistics.getTotalFiles() : 0L);
+            resp.setTotalSize(fileStatistics.getTotalSize() != null ? fileStatistics.getTotalSize() : 0L);
+        }
+        return resp;
+    }
+
     @Transactional(rollbackFor = Exception.class)
     public void addFiles(AddFilesReq request) {
         KnowledgeBase knowledgeBase = Optional.ofNullable(knowledgeBaseRepository.getById(request.getKnowledgeBaseId()))

backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/domain/repository/RagFileRepository.java

@@ -5,6 +5,7 @@ import com.baomidou.mybatisplus.extension.repository.IRepository;
 import com.datamate.rag.indexer.domain.model.RagFile;
 import com.datamate.rag.indexer.interfaces.dto.KnowledgeBaseFileSearchReq;
 import com.datamate.rag.indexer.interfaces.dto.RagFileReq;
+import com.datamate.rag.indexer.interfaces.dto.RagFileStatistics;
 
 import java.util.List;
 
@@ -24,4 +25,6 @@ public interface RagFileRepository extends IRepository<RagFile> {
     IPage<RagFile> page(IPage<RagFile> page, RagFileReq request);
 
     IPage<RagFile> searchPage(IPage<RagFile> page, KnowledgeBaseFileSearchReq request);
+
+    RagFileStatistics getStatistics();
 }

backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/infrastructure/persistence/impl/RagFileRepositoryImpl.java

@@ -8,6 +8,7 @@ import com.datamate.rag.indexer.domain.repository.RagFileRepository;
 import com.datamate.rag.indexer.infrastructure.persistence.mapper.RagFileMapper;
 import com.datamate.rag.indexer.interfaces.dto.KnowledgeBaseFileSearchReq;
 import com.datamate.rag.indexer.interfaces.dto.RagFileReq;
+import com.datamate.rag.indexer.interfaces.dto.RagFileStatistics;
 import org.springframework.stereotype.Repository;
 import org.springframework.util.StringUtils;
 
@@ -60,6 +61,11 @@ public class RagFileRepositoryImpl extends CrudRepository<RagFileMapper, RagFile
                 .page(page);
     }
 
+    @Override
+    public RagFileStatistics getStatistics() {
+        return baseMapper.getStatistics();
+    }
+
     private String normalizeRelativePath(String relativePath) {
         if (!StringUtils.hasText(relativePath)) {
             return "";

backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/infrastructure/persistence/mapper/RagFileMapper.java

@@ -3,7 +3,9 @@ package com.datamate.rag.indexer.infrastructure.persistence.mapper;
 
 import com.baomidou.mybatisplus.core.mapper.BaseMapper;
 import com.datamate.rag.indexer.domain.model.RagFile;
+import com.datamate.rag.indexer.interfaces.dto.RagFileStatistics;
 import org.apache.ibatis.annotations.Mapper;
+import org.apache.ibatis.annotations.Select;
 
 /**
  * RAG文件映射器接口
@@ -13,4 +15,9 @@ import org.apache.ibatis.annotations.Mapper;
  */
 @Mapper
 public interface RagFileMapper extends BaseMapper<RagFile> {
+    @Select("SELECT COUNT(*) AS totalFiles, " +
+        "COALESCE(SUM(df.file_size), 0) AS totalSize " +
+        "FROM t_rag_file rf " +
+        "LEFT JOIN t_dm_dataset_files df ON rf.file_id = df.id")
+    RagFileStatistics getStatistics();
 }

backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/interfaces/KnowledgeBaseController.java

@@ -80,6 +80,16 @@ public class KnowledgeBaseController {
         return knowledgeBaseService.list(request);
     }
 
+    /**
+     * 获取知识库统计信息
+     *
+     * @return 知识库统计信息
+     */
+    @GetMapping("/statistics")
+    public KnowledgeBaseStatisticsResp statistics() {
+        return knowledgeBaseService.getStatistics();
+    }
+
     /**
      * 添加文件到知识库
      *

backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/interfaces/dto/KnowledgeBaseStatisticsResp.java

@@ -0,0 +1,15 @@
+package com.datamate.rag.indexer.interfaces.dto;
+
+import lombok.Getter;
+import lombok.Setter;
+
+/**
+ * 知识库统计响应
+ */
+@Getter
+@Setter
+public class KnowledgeBaseStatisticsResp {
+    private Long totalKnowledgeBases = 0L;
+    private Long totalFiles = 0L;
+    private Long totalSize = 0L;
+}

backend/services/rag-indexer-service/src/main/java/com/datamate/rag/indexer/interfaces/dto/RagFileStatistics.java

@@ -0,0 +1,14 @@
+package com.datamate.rag.indexer.interfaces.dto;
+
+import lombok.Getter;
+import lombok.Setter;
+
+/**
+ * 知识库文件统计
+ */
+@Getter
+@Setter
+public class RagFileStatistics {
+    private Long totalFiles = 0L;
+    private Long totalSize = 0L;
+}