刚开始看了上面很多人写的，发现各种情况都有，最后根据廖老师留下的代码，再未改动他的代码下，利用2层case嵌套循环完成了此题。

package com.itranswarp.learnjava;

import java.util.Scanner;

/**
 * switch实现石头/剪子/布并判断胜负
 */
public class Main {

	@SuppressWarnings("preview")
	public static void main(String[] args) {
		System.out.println("please choice:");
		System.out.println(" 1: Rock(石头)");
		System.out.println(" 2: Scissors(剪刀)");
		System.out.println(" 3: Paper(布)");
		// 用户输入:
		Scanner sc = new Scanner(System.in);
		int choice = sc.nextInt();
		sc.close();

		// 计算机随机数 1, 2, 3:
		int random = 1 + (int) Math.random() * 3;
		// Math.random() * 3产生一个大于等于0小于3的随机数

		System.out.printf("The computer choice is:%d\n", random);

		switch (choice) {
		case 1 -> {
			switch (random) {
			case 1 -> System.out.println("平局!");
			case 2 -> System.out.println("你赢了！");
			case 3 -> System.out.println("你输了！");
			default -> throw new IllegalArgumentException("Unexpected value: " + random);
			}
		}
		case 2 -> {
			switch (random) {
			case 1 -> System.out.println("你输了！");
			case 2 -> System.out.println("平局");
			case 3 -> System.out.println("你赢了！");
			default -> throw new IllegalArgumentException("Unexpected value: " + random);
			}
		}
		case 3 -> {
			switch (random) {
			case 1 -> System.out.println("你赢了！");
			case 2 -> System.out.println("你输了！");
			case 3 -> System.out.println("平局");
			default -> throw new IllegalArgumentException("Unexpected value: " + random);
			}
		}
		default -> throw new IllegalArgumentException("Unexpected value: " + choice);
		}
	}
}