如何使用多部分/表单和分块编码在 spring mvc 中接收文件上传？

Question

我正在尝试编写一个 spring mvc 方法，该方法可以接收多部分/表单或传输编码分块文件上传。我可以编写一个单独的方法来处理每种类型，但我想用相同的方法来做，所以我可以使用相同的 REST POST uri，例如：

http://host:8084/attachments/testupload

这是我迄今为止最好的尝试：

@RequestMapping(value = { "/testupload" }, method = RequestMethod.POST, produces = 
  "application/json")
public @ResponseBody
ResponseEntity<MessageResponseModel> testUpload(
  @RequestParam(value = "filedata", required = false) MultipartFile filedata,
  final HttpServletRequest request) throws IOException {

  InputStream is = null;
  if (filedata == null) {
    is = request.getInputStream();
  }
  else {
    is = filedata.getInputStream();
  }
  byte[] bytes = IOUtils.toByteArray(is);
  System.out.println("read " + bytes.length + " bytes.");

  return new ResponseEntity<MessageResponseModel>(null, null, HttpStatus.OK);
}

使用上述方法我可以上传一个多部分文件，但是如果我上传一个分块文件，我会从 spring 中得到一个异常：

org.springframework.web.multipart.MultipartException: \
The current request is not a multipart request

如果我删除 MultipartFile 请求参数，它非常适合传输编码分块。如果我把它留在里面，它非常适合 MultipartFile 上传。如何使用相同的方法来处理两种上传类型？

这适用于分块：

@RequestMapping(value = { "/testupload" }, method = RequestMethod.POST, produces = 
  "application/json")
public @ResponseBody
ResponseEntity<MessageResponseModel> testUpload(
  final HttpServletRequest request) throws IOException {

  InputStream is = null;
  is = request.getInputStream();
  byte[] bytes = IOUtils.toByteArray(is);
  System.out.println("read " + bytes.length + " bytes.");

  return new ResponseEntity<MessageResponseModel>(null, null, HttpStatus.OK);
}

这对 MultipartFile 非常有用：

@RequestMapping(value = { "/testupload" }, method = RequestMethod.POST, produces = 
  "application/json")
public @ResponseBody
ResponseEntity<MessageResponseModel> testUpload(
  @RequestParam MultipartFile filedata) throws IOException {

  InputStream is = null;
  is = filedata.getInputStream();
  byte[] bytes = IOUtils.toByteArray(is);
  System.out.println("read " + bytes.length + " bytes.");

  return new ResponseEntity<MessageResponseModel>(null, null, HttpStatus.OK);
}

应该是可以的，有人知道怎么做吗？

谢谢， 史蒂夫

Answer 1

摘自我的代码（Spring 3.2，使用 AngularJS 上传 blueimp 文件）：

/**
 * Handles chunked file upload, when file exceeds defined chunked size.
 * 
 * This method is also called by modern browsers and IE >= 10
 */
@RequestMapping(value = "/content-files/upload/", method = RequestMethod.POST, headers = "content-type!=multipart/form-data")
@ResponseBody
public UploadedFile uploadChunked(
        final HttpServletRequest request,
        final HttpServletResponse response) {

    request.getHeader("content-range");//Content-Range:bytes 737280-819199/845769
    request.getHeader("content-length"); //845769
    request.getHeader("content-disposition"); // Content-Disposition:attachment; filename="Screenshot%20from%202012-12-19%2017:28:01.png"
    request.getInputStream(); //actual content.

    //Regex for content range: Pattern.compile("bytes ([0-9]+)-([0-9]+)/([0-9]+)");
    //Regex for filename: Pattern.compile("(?<=filename=\").*?(?=\")");

    //return whatever you want to json
    return new UploadedFile();
}

/**
 * Default Multipart file upload. This method should be invoked only by those that do not
 * support chunked upload.
 * 
 * If browser supports chunked upload, and file is smaller than chunk, it will invoke
 * uploadChunked() method instead.
 * 
 * This is instead a fallback method for IE <=9
 */
@RequestMapping(value = "/content-files/upload/", method = RequestMethod.POST, headers = "content-type=multipart/form-data")
@ResponseBody
public HttpEntity<UploadedFile> uploadMultipart(
        final HttpServletRequest request,
        final HttpServletResponse response,
        @RequestParam("file") final MultipartFile multiPart) {

    //handle regular MultipartFile

    // IE <=9 offers to save file, if it is returned as json, so set content type to plain.
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.TEXT_PLAIN);
    return new HttpEntity<>(new UploadedFile(), headers);
}

这应该可以帮助您入门。在 IE8、IE9、IE10、Chrome、FF 上进行的测试最少。当然可能存在问题，并且可能有一种更简单的提取内容范围的方法，但是 .. 对我有用。

Answer 2

这是控制器

package com.faisalbhagat.web.controller;

@Controller
@RequestMapping(value = { "" })
public class UploadController {

    @RequestMapping(value = "/uploadMyFile", method = RequestMethod.POST)
    @ResponseBody
    public String handleFileUpload(MultipartHttpServletRequest request)
            throws Exception {
        Iterator<String> itrator = request.getFileNames();
        MultipartFile multiFile = request.getFile(itrator.next());
                try {
            // just to show that we have actually received the file
            System.out.println("File Length:" + multiFile.getBytes().length);
            System.out.println("File Type:" + multiFile.getContentType());
            String fileName=multiFile.getOriginalFilename();
            System.out.println("File Name:" +fileName);
            String path=request.getServletContext().getRealPath("/");

            //making directories for our required path.
            byte[] bytes = multiFile.getBytes();
            File directory=    new File(path+ "/uploads");
            directory.mkdirs();
            // saving the file
            File file=new File(directory.getAbsolutePath()+System.getProperty("file.separator")+picture.getName());
            BufferedOutputStream stream = new BufferedOutputStream(
                    new FileOutputStream(file));
            stream.write(bytes);
            stream.close();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            throw new Exception("Error while loading the file");
        }
        return toJson("File Uploaded successfully.")
    }

    public String toJson(Object data)
    {
        ObjectMapper mapper=new ObjectMapper();
        StringBuilder builder=new StringBuilder();
        try {
            builder.append(mapper.writeValueAsString(data));
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return builder.toString();
    }
}

您可以使用客户端代码在以下位置找到完整的解决方案 http://faisalbhagat.blogspot.com/2014/09/springmvc-fileupload-with-ajax-and.html