获取26位不同的字符串

public static synchronized String getSUID(String user_no) { seqno++; if (seqno == 9999999) { seqno = 0; return user_no + System.currentTimeMillis() + "0000001"; } else { return user_no + System.currentTimeMillis() + IN1Util.dupStr(String.valueOf(seqno), 7); } } public static String dupStr(String str, int length) { StringBuffer sb = new StringBuffer(); int len = str.length(); if (len >= length) return str.substring(len - length, len); len = length - len; for (int i = 0; i