java扑克洗牌实现

[size=medium]前段时间，面试某知名公司的时候，被问到洗牌技术。当时，没有好的思路，结果，悲剧....
现整理思路如下：
假设洗54张牌，数组pokers存放每张牌的名字，pokersId存放牌的id，洗牌的过程使pokersId随机化。随机思路为产生两个随机数（合适范围），交互这两个位置的牌Id.重复该过程一定次数，原则上至少等于牌的张数。[/size]

package cn.edu.hust.cs.j2se.test;

import java.util.Date;
import java.util.Random;

public class ShakePoker {
	public static void shake(int[] pokers, int times) {
		System.out.println("shaking....");
		int pos1 = 0;
		int pos2 = 0;
		int tmp = 0;
		int max = pokers.length;
		if (times < pokers.length) {
			times = pokers.length;
		}
		Random rand = new Random(new Date().getTime());
		for (int i = 0; i < times; i++) {
                            //产生随机数
			pos1 = rand.nextInt(max) % pokers.length;
			pos2 = rand.nextInt(max) % pokers.length;
                           //交换id
			tmp = pokers[pos1];
			pokers[pos1] = pokers[pos2];
			pokers[pos2] = tmp;
		}
	}

	public static void main(String[] args) {
		int[] pokersId = new int[54];
		String[] pokers = new String[54];
		//红桃♥heart方块♦diamond 黑桃♠spade 梅花♣club
		String[] groupName = {"♥","♦","♠","♣"};
		String[] pokerName = {"1","2","3","4","5","6","7","8","9","10","J","Q","K"};
                  //初始化数据
		for(int i=0;i<groupName.length;i++){
			for(int j=0;j<pokerName.length;j++){
				pokers[i*pokerName.length + j] = groupName[i] + pokerName[j];
			}
		}
		pokers[52] = "JOKER";//大王
		pokers[53] = "joker";//小王

		int max = pokersId.length;
		for (int i = 0; i < pokersId.length; i++) {
			pokersId[i] = i;
		}
		shake(pokersId, max);
		System.out.println("after shake....");
		for (int i = 0; i < pokersId.length; i++) {
			System.out.print(pokers[pokersId[i]] + " ");
			if(((i+1)%13)==0){
				System.out.println();
			}
		}
	}

}

测试结果大致为

shaking....
after shake....
♠2 ♦8 ♦9 ♥9 ♥5 JOKER ♠Q ♣5 ♠K ♠1 ♥2 ♥K ♣7
♥J ♦6 ♠J ♦4 ♥Q ♦3 ♦10 ♣2 ♣3 ♥3 ♥4 ♥1 ♦K
♥6 ♦7 ♥7 ♣K ♠5 ♠6 ♥8 ♠8 ♠3 ♣6 ♥10 ♣4 ♠7
♣1 ♦Q ♦5 ♠10 ♠9 ♦1 ♣J ♣10 ♠4 ♦J ♣9 joker ♦2
♣Q ♣8