//上传图片
		@At("/uploadimg")
		@Ok("json")
	    @AdaptBy(type = UploadAdaptor.class,args = { "/uploadTemp", "8192", "UTF-8", "1000" })  
	    public NutMap upload(  
	                @Param("image_file") TempFile  tf,  
	                HttpServletRequest req,  
	                ServletContext context) throws SQLException, IOException {  

			
	     NutMap  m=new NutMap();
	     String md5;
	     String prefix;
	     long nowtime=System.currentTimeMillis();
	        @SuppressWarnings("deprecation")
	      
			InputStream fis = tf.getInputStream();   
	        File f = tf.getFile();    // 这个是保存的临时文件
	        FieldMeta meta = tf.getMeta();
	   
	        prefix =   getprefix(f);
	  
	        Iterator readers = ImageIO.getImageReadersByFormatName("jpg");
	    	 ImageReader reader=(ImageReader)readers.next();
	    	 ImageInputStream iis = ImageIO.createImageInputStream(fis);     
	         reader.setInput(iis, true);     
	    	 ImageReadParam param=reader.getDefaultReadParam();
	    	 
	    	 
	    	 
	    	 Rectangle rect= new Rectangle(0, 0, 10, 10);
	    	 param.setSourceRegion(rect);
	    	 
	    	 BufferedImage bi=reader.read(0, param);
	    	 
	    	  ImageIO.write(bi, "jpg", new File("E:\\upload\\jxweike\\" +nowtime+"."+ prefix)); 

报错了 在倒数第二行，生成图片的时候报错了 Not a jpeg file

正如 群里大佬所说，上传的图片是jpg 后缀 但不是jpeg 格式的，   对于这种情况   代码改如何改进，求大佬指点   ！我是要实现剪切头像的功能的！