refactor(llm): 重构数据集示例文件下载功能

- 使用 ResponseEntity 返回文件，提高代码可读性和可维护性
-引入 FileInfoVO 类封装文件信息，简化代码结构
- 优化文件路径和 Content-Type 的处理逻辑
- 增加对文件不存在情况的异常处理
-代码风格统一，提高整体代码质量

yudao-module-llm/yudao-module-llm-biz/src/main/java/cn/iocoder/yudao/module/llm/controller/admin/dataset/DatasetController.java

@@ -6,27 +6,32 @@ import cn.iocoder.yudao.framework.common.pojo.PageParam;
 import cn.iocoder.yudao.framework.common.pojo.PageResult;
 import cn.iocoder.yudao.framework.common.util.object.BeanUtils;
 import cn.iocoder.yudao.framework.excel.core.util.ExcelUtils;
-import cn.iocoder.yudao.module.llm.controller.admin.dataset.vo.DatasetPageReqVO;
-import cn.iocoder.yudao.module.llm.controller.admin.dataset.vo.DatasetRespVO;
-import cn.iocoder.yudao.module.llm.controller.admin.dataset.vo.DatasetSaveReqVO;
-import cn.iocoder.yudao.module.llm.controller.admin.dataset.vo.DatasetTreeNode;
+import cn.iocoder.yudao.module.llm.controller.admin.dataset.vo.*;
 import cn.iocoder.yudao.module.llm.dal.dataobject.dataset.DatasetDO;
 import cn.iocoder.yudao.module.llm.service.dataset.DatasetService;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
 import io.swagger.v3.oas.annotations.tags.Tag;
 import org.apache.commons.io.IOUtils;
+import org.apache.tomcat.jni.FileInfo;
 import org.springframework.core.io.ClassPathResource;
+import org.springframework.core.io.InputStreamResource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.*;
 
 import javax.annotation.Resource;
+import javax.servlet.ServletOutputStream;
 import javax.servlet.http.HttpServletResponse;
 import javax.validation.Valid;
-import java.io.FileNotFoundException;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
+import java.io.*;
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.util.Base64;
 import java.util.List;
 
 import static cn.iocoder.yudao.framework.apilog.core.enums.OperateTypeEnum.EXPORT;
@@ -104,50 +109,37 @@ public class DatasetController {
 
     @GetMapping("/download-example")
     @Operation(summary = "下载示例文件")
-    public void downloadExampleFile (@RequestParam("type") int type, HttpServletResponse response) throws IOException {
-        String fileName;
-        String contentType;
+    public ResponseEntity<InputStreamResource> downloadExampleFile(@RequestParam("type") int type, HttpServletResponse response) throws IOException {
+        FileInfoVO fileInfo = getFileInfo(type);
 
-        // 根据 type 参数确定文件名和 Content-Type
+        // 从 resources/file/dataset_example 目录加载文件
+        ClassPathResource resource = new ClassPathResource("file/dataset_example/" + fileInfo.getFileName());
+        if (!resource.exists()) {
+            throw new FileNotFoundException("文件未找到: " + fileInfo.getFileName());
+        }
+
+        InputStream inputStream = resource.getInputStream();
+        HttpHeaders headers = new HttpHeaders();
+        headers.add("Content-Disposition", "attachment; filename=\"" + URLEncoder.encode(fileInfo.getFileName(), "UTF-8") + "\"");
+
+        return ResponseEntity.ok()
+                .headers(headers)
+                .contentType(MediaType.APPLICATION_OCTET_STREAM)
+                .body(new InputStreamResource(inputStream));
+    }
+
+    private FileInfoVO getFileInfo(int type) {
         switch (type) {
-            // txt 文件
             case 1:
-                fileName = "dataset_example_txt.txt";
-                contentType = "text/plain";
-                break;
-            // xlsx
+                return new FileInfoVO("dataset_example_txt.txt", "text/plain");
             case 2:
-                fileName = "dataset_example_xlsx.xlsx";
-                contentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
-                break;
-            // csv
+                return new FileInfoVO("dataset_example_xlsx.xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
             case 3:
-                fileName = "dataset_example_csv.csv";
-                contentType = "text/csv";
-                break;
-            // json
+                return new FileInfoVO("dataset_example_csv.csv", "text/csv");
             case 4:
-                fileName = "dataset_example_json.json";
-                contentType = "application/json";
-                break;
+                return new FileInfoVO("dataset_example_json.json", "application/json");
             default:
                 throw new IllegalArgumentException("无效的 type 参数");
         }
-
-        // 从 resources/file/dataset_example 目录加载文件
-        ClassPathResource resource = new ClassPathResource("file/dataset_example/" + fileName);
-        if (!resource.exists()) {
-            throw new FileNotFoundException("文件未找到: " + fileName);
-        }
-
-        // 设置响应头
-        response.setContentType(contentType);
-        response.setHeader("Content-Disposition", "attachment; filename=" + fileName);
-
-        // 将文件内容写入响应输出流
-        try (InputStream inputStream = resource.getInputStream();
-             OutputStream outputStream = response.getOutputStream()) {
-            IOUtils.copy(inputStream, outputStream);
-        }
     }
 }

yudao-module-llm/yudao-module-llm-biz/src/main/java/cn/iocoder/yudao/module/llm/controller/admin/dataset/vo/FileInfoVO.java

@@ -0,0 +1,14 @@
+package cn.iocoder.yudao.module.llm.controller.admin.dataset.vo;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+/**
+ * @Description
+ */
+@Data
+@AllArgsConstructor
+public class FileInfoVO {
+    private String fileName;
+    private String contentType;
+}