/**
    * 将Map中的参数组装成URL参数
    *    
    * @param paramMap
    * @return
    */
  public static StringBuffer mapToURL(Map<String, String> paramMap) {
    StringBuffer sb = new StringBuffer();
    List<String> keySet = new ArrayList<String>(paramMap.keySet());
    Collections.sort(keySet);
    for (int i = 0; i < paramMap.size(); i++) {
      if (paramMap.get(keySet.get(i)).equals("bbb")) {
        continue;
      }
      sb.append("&").append(keySet.get(i)).append("=").append(
          paramMap.get(keySet.get(i)));
    }
    sb.delete(0, 1);
    return sb;
  }