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);
}