code: private static String doRequestWithBody(String url, String method, Map<String, String> header, String ctype, byte[] content, int connectTimeout, int readTimeout) throws IOException {
      HttpURLConnection conn = null;
      OutputStream out = null;
      String rsp = null;
      try {
        try {
          conn = getConnection(new URL(url), method, header, ctype);
          conn.setConnectTimeout(connectTimeout);
          conn.setReadTimeout(readTimeout);
        } catch (IOException e) {
          throw e;
        }
        try {
          out = conn.getOutputStream();
          out.write(content);
          rsp = getResponseAsString(conn);
        } catch (IOException e) {
          throw e;
        }
  
      } finally {
        if (out != null) {
          out.close();
        }
        if (conn != null) {
          conn.disconnect();
        }
      }
      return rsp;
    }
docs: 执行HTTP POST请求。
  
  @param url     请求地址
  @param ctype   请求类型
  @param content 请求字节数组
  @return 响应字符串
  @throws IOException