Spring mvc 上传图片MultipartFile 一直为空

1.最近写图片上传功能，需求就是上传图片返回图片路径

@RequestMapping(value = "/fileUpload",method=RequestMethod.POST)  
	public @ResponseBody ComResponse fileUpload( @RequestParam("uploadFile") MultipartFile uploadFile,HttpServletRequest httpServletRequest) {  
		ComResponse response=new ComResponse();
	try {  
	        
	        String filename = uploadFile.getOriginalFilename();  
	        String tempPath=httpServletRequest.getSession().getServletContext().getRealPath("");
	        String realPath =System.getProperty("user.dir")+SEPARTOR+"src"+SEPARTOR+"main"+SEPARTOR+"webapp"+SEPARTOR+"WEB-SCR"+SEPARTOR+"img"+SEPARTOR;
	        System.out.println(realPath);
	        // 如果服务器已经存在和上传文件同名的文件，则输出提示信息  
	        File tempFile = new File(realPath + filename);  
	        if (tempFile.exists()) {  
	            boolean delResult = tempFile.delete();  
	            System.out.println("删除已存在的文件：" + delResult);  
	        }  
	        // 开始保存文件到服务器  
	        if (!StringUtils.isEmpty(filename)) {  
	            FileOutputStream fos = new FileOutputStream(realPath + filename); 
	            BufferedOutputStream bos=new BufferedOutputStream(fos);
	            InputStream is = uploadFile.getInputStream();  
	            int temp;
	            while((temp=is.read())!=-1){
	            	bos.write(temp);
	            }
 
	            bos.close();  
	            fos.close(); // 关闭FileOutputStream对象  
	            is.close(); // InputStream对象  
	            response.setResultData("/WEB-SCR/img/"+filename);
	            response.setStatusCode(ResponseCode.SYS_SUCCESS);
	            response.setStatusDesc("上传成功");
	        }  
	        
	    } catch (FileNotFoundException e) {  
	        e.printStackTrace();  
	    } catch (IOException e) {  
	        e.printStackTrace();  
	    }
	return response;
	}

2.调试时候发现uploadFile=null，少配置这个

3.maven

                
			commons-fileupload
			commons-fileupload
			1.3.1