switch语句中的java扫描程序问题

Question

我试图在一个方法中添加一个switch语句，然后将该方法放在另一个switch语句中。它没有像我预期的那样成功当我执行程序时，控制台希望我立即添加一个用户输入，这不是我想要的

以下是我执行程序后控制台中显示的内容：

qwerty

Greetings, dear Pilgrim. What is thine name?

Bob

Hello, Bob. Is thou ready to start thine quest? [Yes or No]

Please use capital letters... [Yes or No]

应用程序代码

import java.util.Scanner;

public class rolePlay {

    static Scanner player = new Scanner(System.in);
    static String system;
    static String choice = player.nextLine();

    public void letterError() {
        System.out.println("Please use capital letters...");
        System.out.println(system);

        switch (choice) {

        case "Yes" : System.out.println("May thine travels be shadowed upon by Talos...");
        break;
        case "No" : System.out.println("We shall wait for thee...");
        break;
        default: 
        break;
        }
    }
    public rolePlay() {

    }

    public static void main(String[] args) {

        rolePlay you = new rolePlay();

        System.out.println("Greetings, dear Pilgrim. What is thine name?");
        String charName = player.nextLine();
        System.out.println("Hello, " + charName + ". Is thou ready to start thine quest?");

        system = "[Yes or No]";
        System.out.println(system);
        //String choice = player.nextLine();

        switch (choice) {

        case "Yes" : System.out.println("May thine travels be shadowed upon by Talos...");
        break;
        case "No" : System.out.println("We shall wait for thee...");
        break;
        default : you.letterError();
        break;
        }

        player.close();
    }
}

Answer 1

static String choice = player.nextLine();

当第一次访问该类时，该行只被调用一次。这就是为什么它需要用户立即输入。您需要在想要获取用户输入时调用player.nextLine()；在这种情况下，您应该在每个switch语句之前调用它，就像您注释掉的那行一样

Answer 2

调用player.nextLine()并将其分配给静态变量choice会导致问题。静态变量在第一次调用类时被检索，在您的例子中，这意味着在调用main方法之前。相反，当您希望用户向控制台输入内容时，不应该在main方法内部为choice赋值，也不应该为player.nextLine()赋值

    System.out.println("Greetings, dear Pilgrim. What is thine name?");
    String charName = player.nextLine();
    System.out.println("Hello, " + charName + ". Is thou ready to start thine quest?");

    system = "[Yes or No]";
    System.out.println(system);
    choice = player.nextLine();     

从Static String choice声明中删除player.nextLine()之后应该是这样的