最近进行restapi上传文件接口开发，在上传文件类型的时候，遇到了在本地可以正常使用，项目部署到linux上时又无法使用的情况，解决如下：

    /**
	 * MultipartFile 转 File
	 * @param file
	 * @throws Exception
	 */
	public static void multipartFileToFile( @RequestParam MultipartFile file ) throws Exception {

	    File toFile = null;
	    if(file.equals("")||file.getSize()<=0){
	        file = null;
	    }else {
	            InputStream ins = null;
	            ins = file.getInputStream();
	            toFile = new File(file.getOriginalFilename());
	            inputStreamToFile(ins, toFile);
	            ins.close();
	    }

	}

开发时发现，该方法只在windows下可正常使用，项目部署到linux上后使用就有问题了

     /**
	  * File 转 MultipartFile（仅windows）
	  * @param file
	  * @throws Exception
	  */
	 public static MultipartFile fileToMultipartFile(File file) throws Exception {
		 MultipartFile multipartFile = null;
		 try {
				FileInputStream input = new FileInputStream(file);
				multipartFile = new MockMultipartFile("file", file.getName(), "text/plain", IOUtils.toByteArray(input));
		 } catch (Exception e) {
				e.printStackTrace();
		 }
		 return multipartFile;
	 }

该方法兼容windows和linux(推荐使用)

/**
	  * File 转 MultipartFile2(该方法兼容windows和linux)
	  * @param picPath
	  * @return
	  */
	 public static MultipartFile getMulFileByPath(String picPath) {  
	        FileItem fileItem = createFileItem(picPath);  
	        MultipartFile mfile = new CommonsMultipartFile(fileItem);  
	        return mfile;  
	 }  
	 
	 public static FileItem createFileItem(String filePath) {
		 	File file=new File(filePath);
		    FileItemFactory factory = new DiskFileItemFactory(16, null);
		    String textFieldName = "file";
		    int num = filePath.lastIndexOf(".");
		    String extFile = filePath.substring(num);
		    FileItem item = factory.createItem(textFieldName, "text/plain", true, file.getName());
		    File newfile = new File(filePath);
		    int bytesRead = 0;
		    byte[] buffer = new byte[8192];
		    try {
		        FileInputStream fis = new FileInputStream(newfile);
		        OutputStream os = item.getOutputStream();
		        while ((bytesRead = fis.read(buffer, 0, 8192)) != -1) {
		            os.write(buffer, 0, bytesRead);
		        }
		        os.close();
		        fis.close();
		    } catch (IOException e) {
		        e.printStackTrace();
		    }
		    return item;
	 }