code: public static String getPostString(InputStream is, String encoding) {
          try {
              StringWriter sw = new StringWriter();
              IOUtils.copy(is, sw, encoding);
  
              return sw.toString();
          } catch (IOException e) {
              // no op
              return null;
          } finally {
              IOUtils.closeQuietly(is);
          }
      }
docs: get string from post stream
  
  @param is
  @param encoding
  @return