数组打乱

package com.yenange.test;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class TestListShuffle {
public static void main(String[] args) {
Integer [] arr=new Integer[20];
List list=new ArrayList();
for (int i = 1; i <= 10; i++) {
for (int j = 1; j <= 2; j++) {
list.add(Integer.valueOf(i));
}
}
arr=(Integer[])list.toArray(new Integer[20]);
System.out.println("最初的:");
printArr(arr);
Collections.shuffle(list);
arr=(Integer[])list.toArray(new Integer[20]);
System.out.println("/n打乱后的:");
printArr(arr);
}

private static void printArr(Object[] arr) {
for (int i = 0; i < arr.length; i++) {
if (i%10==0) {
System.out.println();
}
System.out.print(arr[i]+"/t");
}
}
}