Spring Boot + Mongodb :文件上传RESTFUL风格的Web服务

@RestController
@RequestMapping("/api")
public class FileUploadController {
  
  @Autowired
  private MongoTemplate mongoTemplate;
  
  @PostMapping("/upload")
  public ResponseEntity<?> uploadFile(@RequestParam("file") MultipartFile file) {
    try {
      // 保存文件到Mongodb
      GridFSFile gridFsFile = mongoTemplate.store(file.getInputStream(), file.getOriginalFilename());
      ObjectId fileId = (ObjectId) gridFsFile.getId();
      
      // 返回文件的访问链接
      String fileUrl = "https://yourdomain.com/api/download/" + fileId.toHexString();
      return ResponseEntity.ok(fileUrl);
    } catch (Exception e) {
      return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body("File upload failed");
    }
  }
  
  @GetMapping("/download/{fileId}")
  public ResponseEntity<?> downloadFile(@PathVariable String fileId) {
    try {
      // 根据文件ID从Mongodb中获取文件
      GridFSFile gridFsFile = mongoTemplate.findOne(new Query(Criteria.where("_id").is(new ObjectId(fileId))));
      if (gridFsFile == null) {
        return ResponseEntity.notFound().build();
      }
      
      // 返回文件流
      GridFsResource gridFsResource = new GridFsResource(gridFsFile);
      return ResponseEntity.ok().contentType(MediaType.parseMediaType(gridFsResource.getContentType())).body(new InputStreamResource(gridFsResource.getInputStream()));
    } catch (Exception e) {
      return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body("File download failed");
    }
  }
}