【Java基础】Java中switch的多种写法

Java中switch的多种写法

代码需求：键盘录入一个数字（代表星期几），判断是工作日还是休息日

switch最基础写法

	public static void switchTest() {
        while (true) {
            System.out.println("请输入：");
 
            Scanner sc = new Scanner(System.in);
            int num = sc.nextInt();
 
            switch (num) {
                case 1:
                    System.out.println("工作日");
                    break;
                case 2:
                    System.out.println("工作日");
                    break;
                case 3:
                    System.out.println("工作日");
                    break;
                case 4:
                    System.out.println("工作日");
                    break;
                case 5:
                    System.out.println("工作日");
                    break;
                case 6:
                    System.out.println("休息日");
                    break;
                case 7:
                    System.out.println("休息日");
                    break;
                default:
                    System.out.println("输入错误");
                    break;
            }
 
            System.out.println();
        }
    }

switch穿透现象

	public static void switchTest1() {
 
        while (true) {
            System.out.println("请输入：");
 
            Scanner sc = new Scanner(System.in);
            int num = sc.nextInt();
 
            switch (num) {
                case 1:
                case 2:
                case 3:
                case 4:
                case 5:
                    System.out.println("工作日");
                    break;
                case 6:
                case 7:
                    System.out.println("休息日");
                    break;
                default:
                    System.out.println("输入错误");
                    break;
            }
 
            System.out.println();
        }
    }

JDK14之后switch新特性1

    public static void switchTest2() {
 
        while (true) {
            System.out.println("请输入：");
 
            Scanner sc = new Scanner(System.in);
            int num = sc.nextInt();
 
            switch (num) {
                case 1, 2, 3, 4, 5:
                    System.out.println("工作日");
                    break;
                case 6, 7:
                    System.out.println("休息日");
                    break;
                default:
                    System.out.println("输入错误");
                    break;
            }
 
            System.out.println();
        }
    }

JDK14之后switch新特性2

    public static void switchTest3() {
 
        while (true) {
            System.out.println("请输入：");
 
            Scanner sc = new Scanner(System.in);
            int num = sc.nextInt();
 
            switch (num) {
                case 1, 2, 3, 4, 5 -> System.out.println("工作日");
                case 6, 7 -> System.out.println("休息日");
                default -> System.out.println("输入错误");
            }
 
            System.out.println();
        }
    }