如何在Java中从MultipartHttpServletRequest写入文件

问题描述

由于我的后端团队将发送zip文件，如何接收该文件并将其存储到java（eclipse）中的项目位置

我尝试使用MultipartHttpServletRequest编写一些代码，并创建了多部分长度和zip文件夹，但无法提取时显示无效。然后如何写入文件。请帮助我

@RequestMapping(value = "/retrieveBillerByFile1",method = RequestMethod.POST)
    public @ResponseBody void retrieveBillerByFile1(@RequestPart MultipartHttpServletRequest  request) throws Exception 
    {
        System.out.println("RESPONSEEEE**"+request);
        
            Iterator<String> itrator = request.getFileNames();
            System.out.println("File Name:" + request.getFileNames());
            multipartfile multiFile = request.getFile(itrator.next());
            System.out.println("itrator.next()" + itrator.next());
          
            
             try {
                // just to show that we have actually received the file
                     System.out.println("File Length:" + multiFile.getBytes().length);
                  String name = multiFile.getoriginalFilename();
                System.out.println("name" + name);
                
                System.out.println("multiFile.getBytes()" + multiFile.getBytes());
                BufferedWriter w = Files.newBufferedWriter(Paths.get("D:\\cedge_uat\\" + name ));
                w.write(new String(multiFile.getBytes()));
                w.flush();

               
            } catch (Exception e) {
                // Todo Auto-generated catch block
                e.printstacktrace();
                throw new Exception("Error while loading the file");
            }
        
    
}

我尝试过的另一种方法，但fileItem变为null

@RequestMapping(value = "/retrieveBillerByFile",method = RequestMethod.POST)
    public @ResponseBody void retrieveBillerByFile(@RequestPart HttpServletRequest request,HttpServletResponse response) throws Exception 
    {
        System.out.println("RESPONSEEEE**"+request);
        System.out.println("request**"+request);
        
        
          // checks if the request actually contains upload file
        if (!ServletFileUpload.isMultipartContent(request)) {
            System.out.println("Form must has enctype=multipart/form-data.**");
            // if not,we stop here
            PrintWriter writer = response.getWriter();
            writer.println("Error: Form must has enctype=multipart/form-data.");
            writer.flush();
            return;
        }
 
        // configures upload settings
        diskFileItemFactory factory = new diskFileItemFactory();
        // sets memory threshold - beyond which files are stored in disk
        factory.setSizeThreshold(MEMORY_THRESHOLD);
        // sets temporary location to store files
        factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
 
        ServletFileUpload upload = new ServletFileUpload(factory);
         
        // sets maximum size of upload file
        upload.setFileSizeMax(MAX_FILE_SIZE);
         
        // sets maximum size of request (include file + form data)
        upload.setSizeMax(MAX_REQUEST_SIZE);
 
        // constructs the directory path to store upload file
        // this path is relative to application's directory
      //  String uploadpath = servletContext.getRealPath("")+ File.separator + UPLOAD_DIRECTORY;
         
        String uploadpath = servletContext.getRealPath("/WEB-INF/xml") + File.separator + UPLOAD_DIRECTORY;
        // creates the directory if it does not exist
        File uploadDir = new File(uploadpath);
        if (!uploadDir.exists()) {
            uploadDir.mkdir();
        }
        System.out.println("uploadpath\n"+ uploadpath);
        try {
            // parses the request's content to extract file data
            @SuppressWarnings("unchecked")
            List<FileItem> formItems = upload.parseRequest(request);
            System.out.println("formItems**"+formItems);
            if (formItems != null && formItems.size() > 0) {
                // iterates over form's fields
                for (FileItem item : formItems) {
                    System.out.println("item**"+item);
                    // processes only fields that are not form fields
                    if (!item.isFormField()) {
                        String fileName = new File(item.getName()).getName();
                        System.out.println("fileName**"+fileName);
                        String filePath = uploadpath + File.separator + fileName;
                        File storeFile = new File(filePath);
 
                        // saves the file on disk
                        item.write(storeFile);
                        System.out.println("success");
                        request.setAttribute("message","Upload has been done successfully!");
                    }
                }
            }
        } catch (Exception ex) {
            System.out.println("exception"+ ex.getMessage());
            request.setAttribute("message","There was an error: " + ex.getMessage());
        }
        
    }

解决方法

您可以在方法中添加另一个参数-

@RequestParam MultipartFile file

所以您的方法将是-

public @ResponseBody void retrieveBillerByFile1(@RequestParam MultipartFile file,@RequestPart MultipartHttpServletRequest  request) throws Exception 

然后使用Java文件api操作文件