private static String nextIndex() {
        String rs = "";
        synchronized (SerializeHelper.class) {
            rs += ++index < 0 ? -index : index;
            int least = 3 - rs.length();
            for (int i = 0; i < least; i++) {
                rs = "0" + rs;
            }
            return rs;
        }
    }
private static String nextIndex ( ) { String rs = "" ; synchronized ( SerializeHelper . class ) { rs += ++ index < 0 ? - index : index ; int least = 3 - rs . length ( ) ; for ( int i = 0 ; i < least ; i ++ ) { rs = "0" + rs ; } return rs ; } }
返回固定长度的

@return