在带有Try/catch的Switch语句中正确使用Scanner和Random

Question

我正在尝试用Java做一个基于文本的游戏。我会有很多关于scanner的切换语句，但是我不确定哪种方式是最好的。

用Scanner制作switch-statement的最好方法是什么？try+catch更好吗？或者做循环？

如果我有，假设有10个switch-statement。为每个switch语句声明10个不同的Scanner是不是更好？

我喜欢有try+catch风格的开关声明与个人扫描器在它，但有人说这是没有必要的，并采取太多的浪费内存的方式。

下面的代码是示例。这里的代码不是一个好的代码吗？(当涉及到try+catch时，扫描仪的使用情况)

public static void levelUpAsk_111(Character chosenMember) {
    try {
        Random rand = new Random();
        Scanner sc = new Scanner(System.in);
        int dicePercent = rand.nextInt(6) + 1;

        int num = sc.nextInt();
        if (num == dicePercent ) {
            System.out.println("** Congratulation!!");
            sc.nextLine();
            System.out.println("**Which one would you like to increase?");
            System.out.println("1. +20 HP");
            System.out.println("2. +10 MP");
            System.out.println("3. +5 ATT");

            levelUpAsk_222(chosenMember);    //the second method
        } else if (num > 7 || num < 1) {
            System.out.println("Please from 1 to 6");
            levelUpAsk_111(chosenMember);   //recall itself
        } else {
            System.out.println("** Sorry..");
            sc.nextLine();

        }
    } catch (InputMismatchException e) {
        System.out.println("Please integer only");
        levelUpAsk_111(chosenMember);  //recall itself
    }
}





 public static void levelUpAsk_222(Character chosenMember) {
    try {
        Scanner sc = new Scanner(System.in);
        int select = sc.nextInt();

        switch (select) {

        case 1:
            System.out.println("** HP has increased by 20.");
            break;
        case 2:
            System.out.println("** MP has increased by 10.");
            break;
        case 3:
            System.out.println("** ATT has incrased by 5.");
            break;
        default:
            System.out.println("From 1 to 3");
            levelUpAsk_222(chosenMember);  //recall itself
            break;

        }
    } catch (InputMismatchException e) {
        System.out.println("Only integer please");  //recall itself
        levelUpAsk_222(chosenMember);
    }
}

Answer 1

对于switch语句，不需要在每次要使用它时都创建新的Scanner对象。您可以在每个方法的开头声明它一次。如果必须在代码中处理多个Scanner对象，这比只有一个对象更令人困惑。

您可以创建一个带有default:的开关循环菜单来捕获未列出的输入。例如

switch (option){  //assuming you declared option to an int and user has inputted a value for it
    case 1:
        {
        //put some code here
        break;
        }
    case 2:
        {
        //put more code here
        break;
        }
    case 0:
        {
        //used to exit the loop
        break;
        }
    default:
        {
        System.out.println("Please enter a integer only");
        levelUpAsk_111(chosenMember); //you can do it this way, or use a do-while looped switch menu that keeps asking until a valid int is input
        }

}