java实现图片上传并添加水印demo

前段时间研究了图片上传添加水印的效果，现在贴出来供大家参考参考。

/**
 * 图片上传，添加水印
 * @param request
 * @param params
 * @param values
 * @return
 * @throws Exception
 * @author LLJ
 * @date 2016/12/16
 */
public static List<Map<String, Object>> newUpload(HttpServletRequest request,
      String[] params, Map<String, Object[]> values) throws Exception {


   List<Map<String, Object>> result = new ArrayList<Map<String, Object>>();

   MultipartHttpServletRequest mRequest = (MultipartHttpServletRequest) request;
   Map<String, MultipartFile> fileMap = mRequest.getFileMap();

   String relativePath = FileOperateUtil.UPLOADDIR    + DateUtils.dateStr7(new Date()) + "/";
   logger.info("图片relativePath:"+relativePath);
   String uploadDir = request.getSession().getServletContext().getRealPath("/") + "/" + relativePath;
   logger.info("图片uploadDir:"+uploadDir);
   File file = new File(uploadDir);
   if (!file.exists()) {
      file.mkdirs();
   }

   String fileName = null;
   int i = 0;
   for (Iterator<Map.Entry<String, MultipartFile>> it = fileMap.entrySet().iterator(); it.hasNext(); i++) {
      Map<String, Object> map = new HashMap<String, Object>();
      map.put("success", true);
      Map.Entry<String, MultipartFile> entry = it.next();
      MultipartFile mFile = entry.getValue();
      //判断文件格式 和 文件大小
      if(mFile.getSize()/1024D>NEW_LIMIT_SIZE){
         map.put("success", false);
         map.put("msg", "图片仅支持小于3M的jpg、 png.格式");
         result.add(map);
         continue;
      }
      //获取文件名
      fileName = mFile.getOriginalFilename();
      if(fileName.lastIndexOf(".")<0 || fileName.lastIndexOf(".")==fileName.length()-1){
         map.put("success", false);
         map.put("msg", "图片仅支持小于3M的jpg、 png.格式");
         result.add(map);
         continue;
      }
      if(!Pattern.matches("^"+NEW_LIMIT_TYPE+"$", fileName.substring(fileName.lastIndexOf(".")+1))){
         map.put("success", false);
         map.put("msg", "文件上传格式不对，只支持jpg、 png格式");
         result.add(map);
         continue;
      }

      String storeName = rename(fileName);

      String noZipName = uploadDir + storeName;



      String zipName = zipName(noZipName);
      logger.info("图片zipName:"+zipName);
      File uploadFile = new File(uploadDir + storeName);
      FileCopyUtils.copy(mFile.getBytes(), uploadFile);

      // 固定参数值对
      map.put(FileOperateUtil.REALNAME, fileName);
      map.put(FileOperateUtil.STORENAME, storeName);
      map.put(FileOperateUtil.SIZE, new File(zipName).length());
      map.put(FileOperateUtil.SUFFIX, "zip");
      map.put(FileOperateUtil.CONTENTTYPE, "application/octet-stream");
      map.put(FileOperateUtil.CREATETIME, new Date());
      map.put("url", relativePath + storeName);
      logger.info("图片url:"+relativePath + storeName);
      fileName = map.get(FileOperateUtil.STORENAME) + "";
      /**开始：加水印**/
      FileInputStream in=new FileInputStream(uploadDir + "/" + fileName);
       Image src=ImageIO.read(in);
       int w=src.getWidth(null);
       int h=src.getHeight(null);
       float alpha = 0.3f; // 透明度
       BufferedImage img=new BufferedImage(w,h,BufferedImage.TYPE_INT_RGB);//构建画板
       Graphics2D g=img.createGraphics();//得到画笔
       g.drawImage(src,0,0,w,h,null);//把源图片写入画板
       Font fsib30 = new Font("微软雅黑", Font.BOLD + Font.ITALIC, img.getWidth()/16);
       g.setFont(fsib30);
       g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP,alpha));
       g.setColor(Color.black);
       g.setBackground(Color.white);
       g.rotate(Math.toRadians(-15),
               (double) img.getWidth() / 2, (double) img
               .getHeight() / 2);
       g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                 RenderingHints.VALUE_ANTIALIAS_ON);
       String pressText = "仅供XXX认证使用";
       g.drawString(pressText, (w - (getLength(pressText) * img.getWidth()/16))
                 / 2 + 10, (h - img.getWidth()/16) / 2 + 10);
       g.dispose();//生成图片
       OutputStream out = new FileOutputStream(uploadDir + "/" + fileName);
       JPEGImageEncoder en = JPEGCodec.createJPEGEncoder(out);
       en.encode(img);
       /**结束：加水印**/
      // 自定义参数值对
      for (String param : params) {
         map.put(param, values.get(param)[i]);
      }
      result.add(map);
   }
   return result;
}

/**
    * 获取字符长度，一个汉字作为 1 个字符, 一个英文字母作为 0.5 个字符
    * @param text
    * @return 字符长度，如：text="中国",返回 2；text="test",返回 2；text="中国ABC",返回 4.
    */
   public static int getLength(String text) {
       int textLength = text.length();
       int length = textLength;
       for (int i = 0; i < textLength; i++) {
           if (String.valueOf(text.charAt(i)).getBytes().length > 1) {
               length++;
           }
       }
       return (length % 2 == 0) ? length / 2 : length / 2 + 1;
   }