Java实现按比例缩小图片

< div class = "form-group" >

     < label class = "col-lg-1 col-md-1 col-sm-2 col-xs-2 label-size" >< span class = "c-red" >*</ span >头像：</ label >

     < div class = "col-lg-4 col-md-4 col-sm-4 col-xs-4 img-padding-zero" >

         < div >

             < span id = "Upload_ph" class = "img-hide" >

                 < input type = "file" title = "" id = "UploadFile" name = "UploadFile" multiple = "" class = "img-input" >

             </ span >

             < span >

                 < img alt = "" src = "${ctx}/UserManages/reveal_photo.do?file=tree.png" >

                 < a class = "a-word" style = "cursor:pointer;" >上传图片</ a >&nbsp;&nbsp;

                 < a id = "showApellation" class = "a-word" style = "font-size:12px;" ></ a >                

             </ span >

         </ div >

         < div >

             < img src = "${ctx}/UserManages/reveal_photo.do?file=noImg.png" class = "img-padding" width = "198" height = "198" alt = "" id = "imgOperPhoto1" onload = "AutoResizeImage(198, 198, this)" title = "用于头像显示" >

             < img src = "${ctx}/UserManages/reveal_photo.do?file=noImg_tab.png" class = "img-padding" width = "28" height = "40" alt = "" id = "imgOperPhoto3" title = "用于列表显示" >

         </ div >

     </ div >

</ div >

@SuppressWarnings ( "unused" )

@RequestMapping (value= "/IntOpers" )

private void IntOper( @RequestParam (value= "UploadFile" , required= true ) MultipartFile UploadFile, PrintWriter pw, HttpServletRequest request) throws IOException {

     String StrReturn = "error" , FileName = "" , ext = "" ;

     long time = 0 ;

     if (!UploadFile.isEmpty()) {

         if (UploadFile != null ) {

             String fullName = UploadFile.getOriginalFilename();

             ext = fullName.substring(fullName.lastIndexOf( "." )); //获取扩展名称

             time = System.nanoTime();

             FileName = time + ext; //设置文件保存的名称

             //原图

             String upDir = "F:/java/upload-ssm" ; //文件上传路径

             FileUtils.writeByteArrayToFile( new File(upDir, FileName), UploadFile.getBytes());

             //缩小图片

             Image srcFile = ImageIO.read( new File(upDir + "/" + FileName));

             BufferedImage tag = new BufferedImage( 28 , 40 , BufferedImage.TYPE_INT_RGB);

             tag.getGraphics().drawImage(srcFile, 0 , 0 , 28 , 40 , null );

             String FileName_tab = time + "_tab" + ext; //设置文件保存的名称

             FileOutputStream out = new FileOutputStream(upDir + "/" + FileName_tab);

             JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);

             JPEGEncodeParam jep = JPEGCodec.getDefaultJPEGEncodeParam(tag);

             jep.setQuality(1f, true );

             encoder.encode(tag, jep);

             out.close();

             StrReturn = "success" ;

         }

     }

     pw.write(StrReturn);

}