java将数组中的元素颠倒和打乱

颠倒

public static void main(String[] args) {
        //交换数组
        int [] arr1={1,2,3,4,5};
        for (int i = 0,j= arr1.length-1;i<j; i++,j--) {
            int temp=arr1[i];
            arr1[i]=arr1[j];
            arr1[j]=temp;
        }
        for (int i = 0; i < arr1.length; i++) {
            System.out.println(arr1[i]);
        }
}

打乱

public static void main(String[] args) {
        //打乱数组中的顺序
        int [] arr={1,2,3,4,5};
        Random r=new Random();
        for (int i = 0; i < arr.length; i++) {
            int randomIndex=r.nextInt(arr.length);
            int temp=arr[i];
            arr[i]=arr[randomIndex];
            arr[randomIndex]=temp;
        }
        for (int i = 0; i < arr.length; i++) {
            System.out.println(arr[i]);
        }
    }