java 公平打乱数组顺序 重新排列

01.import java.util.Random;    
02.    
03.public class RandomSort {    
04.    private Random random = new Random();    
05.    //数组大小    
06.    private static final int SIZE = 10;    
07.    //要重排序的数组    
08.    private int[] positions = new int[SIZE];    
09.        
10.    public RandomSort() {    
11.        for(int index=0; index<SIZE; index++) {    
12.            //初始化数组，以下标为元素值    
13.            positions[index] = index;    
14.        }    
15.        //顺序打印出数组的值    
16.        printPositions();  
17.    }    
18.        
19.    //重排序    
20.    public void changePosition() {    
21.        for(int index=SIZE-1; index>=0; index--) {    
22.            //从0到index处之间随机取一个值，跟index处的元素交换    
23.            exchange(random.nextInt(index+1), index);    
24.        }    
25.        printPositions();    
26.    }    
27.        
28.    //交换位置    
29.    private void exchange(int p1, int p2) {    
30.        int temp = positions[p1];    
31.        positions[p1] = positions[p2];    
32.        positions[p2] = temp;  //更好位置  
33.    }    
34.        
35.    //打印数组的值    
36.    private void printPositions() {    
37.        for(int index=0; index<SIZE; index++) {    
38.            System.out.print(positions[index]+" ");             
39.        }    
40.        System.out.println();    
41.    }    
42.    
43.    public static void main(String[] args) {    
44.        RandomSort rs = new RandomSort();    
45.        rs.changePosition();    
46.        rs.changePosition();    
47.        rs.changePosition();    
48.    }    
49.}