code: private static String getContent(BufferedReader buff) throws IOException {
          String line;
          StringBuffer content = new StringBuffer();
          while ((line = buff.readLine()) != null) {
              content.append('\n');
              content.append(line);
          }
          return content.substring(1).toString();
      }
docs: 获取BufferedReader对应字符串
  
  @param buff bufferedReader
  @return 内容
  @throws IOException io exception