Java如何去掉指定字符串的开头的指定字符

/**

      * 去掉指定字符串的开头的指定字符

      * @param stream 原始字符串

      * @param trim 要删除的字符串

      * @return

      */

     public static String StringStartTrim(String stream, String trim) {

         // null或者空字符串的时候不处理

         if (stream == null || stream.length() == 0 || trim == null || trim.length() == 0 ) {

             return stream;

         }

         // 要删除的字符串结束位置

         int end;

         // 正规表达式

         String regPattern = "[" + trim + "]*+" ;

         Pattern pattern = Pattern.compile(regPattern, Pattern.CASE_INSENSITIVE);

         // 去掉原始字符串开头位置的指定字符

         Matcher matcher = pattern.matcher(stream);

         if (matcher.lookingAt()) {

             end = matcher.end();

             stream = stream.substring(end);

         }

         // 返回处理后的字符串

         return stream;

     }

public static String truncateHeadString(String origin, int count) {

     if (origin == null || origin.length() < count) {

         return null ;

     }

     char [] arr = origin.toCharArray();

     char [] ret = new char [arr.length - count];

     for ( int i = 0 ; i < ret.length; i++) {

         ret[i] = arr[i + count];

     }

     return String.copyValueOf(ret);

}