随机数字

package com;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Random;

public class TestLuckyNum {

public static final SimpleDateFormat sdfTime = new SimpleDateFormat("ssS");

public static void main(String[] args) {

System.out.println(getRandomReqSn("###"));

}

/**
* 取随机数
* @param PrtNo 投保书确认号
* @return
*/
private static String getRandomReqSn(String PrtNo){

Random ran = new Random();
        int bitField = 0;
        char[] chs = new char[4];
        for (int i = 0; i < 4; i++) {
            while(true) {
                int k = ran.nextInt(10);
                if( (bitField & (1 << k)) == 0) {
                    bitField |= 1 << k;
                    chs[i] = (char)(k + '0');
                    break;
                }
            }
        }

        //投保书确认号 + 当前时间 hhmmss + 4位随机数
        String randomReqSn = PrtNo.trim()+sdfTime.format(new Date())+new String(chs);
       
return randomReqSn;
}

}