去除首尾空格

public static String trimFirstAndLastChar(String str, String element){
      boolean beginIndexFlag = true;
      boolean endIndexFlag = true;
      do{
              int beginIndex = str.indexOf(element) == 0 ? 1 : 0;
             int endIndex = str.lastIndexOf(element) + 1 == str.length() ? str.lastIndexOf(element) : str.length();
             str = str.substring(beginIndex, endIndex);
              beginIndexFlag = (str.indexOf(element) == 0);
              endIndexFlag = (str.lastIndexOf(element) + 1 == str.length());
          } while (beginIndexFlag || endIndexFlag);
      return str;
  }