如何检查一个字符串的扫描器是否相等并在Java中使用它？

Question

The following is an excerpt from a program I'm trying to make. I want to get it so when someone enters in the phrase "Yes" or "No" it gets the response in the if-statements. Notice they are placeholders for now, I plan on doing something more with those statements.

Please also take note that the code is incomplete, so it may not make complete sense, but my question should still.

Main class:

package adventure;

import java.util.Scanner;

public class Main {
    int boots, leggings, chestplate, helm;
    static int hp = 25;
    int dogde;
    int dagger = 1;
    int ssword = 0;
    int lsword = 0;
    int shield = 0;
    static int strength = 1;
    static int agility = 1;
    static int health = 25;
    int stats, inventory;
    static int gold = 10;
    static int x = 0;
    int senemy = 0, menemy = 0, lenemy = 0, boss = 0;
    public static void main (String[]args)  {

        System.out.println("Welcome to the adventure game! Enter 0 to start"); 
        Scanner sc = new Scanner(System.in);
        int menu = sc.nextInt();
            if (menu == 0)  {
                System.out.println("Welcome to the menu! It can be reopened anytime by entering 0");
                System.out.println("Enter:");
                System.out.println("1 to view player stats");
                System.out.println("2 to view your inventory");
                System.out.println("3 to view your gold amount");
                System.out.println("4 to continue your adventure");
        while (x == 0)
            switch (sc.nextInt())   {
            case 1:
                System.out.println("You have " + hp + " out of " + health + " hp, " + agility + " agility and " + strength + " strength");
                break;
            case 2:
                System.out.println("You have ");
                break;
            case 3:
                System.out.println("You have " + gold + " gold");
                break;
            case 4:
                System.out.println("Let the adventure begin..."); x=2;
                break;
            default:
                System.out.println("Menu exited"); x=1;
                break;
            }
        }
            if (x == 2){
                Level1 level1Object = new Level1();

            }
    }
}

My particular concern is with case 2.

package adventure;
import java.util.Scanner;

public class Level1 {
String yes = "Yes";
String no = "No";
{   Scanner sc = new Scanner(System.in);
    int x = 2;
    System.out.println("Level 1 out of 12");
    System.out.println("You wake up in a town called Haven");
    System.out.println("Enter:");
    System.out.println("1 = Visit the armory, 2 = Find a quest, 3 = Proceed to the next level");
    while (x == 2){
    switch (sc.nextInt()){ 
    case 1:
        System.out.println("You enter the armory"); //placeholder
        break;
    case 2:
        System.out.println("You ask the local guard captain for a quest");
        System.out.println("Captain: Orcs have taken the south watchtower, take it back and I will reward you 10 gold");
        System.out.println("Accept quest? Enter: Yes or No");
        String input = sc.nextLine();
        System.out.println(input);
        if (input.equals("Yes"))    {
            System.out.println("Quest accepted"); //placeholder
        }
        else if (input.equals("No"))    {
            System.out.println("Quest denied"); //placeholder
        }
        break; //placeholder
    case 3:
        System.out.println("You proceed to the next level"); //placeholder
        break;
    default:
        System.out.println("Invalid response");
        System.out.println(0); //test, delete
        break;
        }
    }
    }
}

Error:

Exception in thread "main" java.util.InputMismatchException
    at java.util.Scanner.throwFor(Scanner.java:840)
    at java.util.Scanner.next(Scanner.java:1461)
    at java.util.Scanner.nextInt(Scanner.java:2091)
    at java.util.Scanner.nextInt(Scanner.java:2050)
    at adventure.Level1.<init>(Level1.java:14)
    at adventure.Main.main(Main.java:52)

EDIT I fixed it by changing the "No" line to look like the "Yes" one and used another scanner than the 'sc' one.

Answer 1

import java.io.FileNotFoundException;
import java.util.HashMap;
import java.util.Map;

import java.util.Scanner;

public class Level1 {
 private static String YES = "Yes";
 private static String NO = "No";

 public Level1(){
Scanner sc = new Scanner(System.in);
    int x = 2;
    System.out.println("Level 1 out of 12");
    System.out.println("You wake up in a town called Haven");
    System.out.println("Enter:");
    System.out.println("1 = Visit the armory, 2 = Find a quest, 3 = Proceed to the next level");
    while (x == 2){
     switch (sc.nextInt()){ 
      case 1:
       System.out.println("You enter the armory"); //placeholder
       break;
      case 2:
       System.out.println("You ask the local guard captain for a quest");
       System.out.println("Captain: Orcs have taken the south watchtower, take it back and I will reward you 10 gold");
       System.out.println("Accept quest? Enter: Yes or No");
       String input = sc.nextLine();
       System.out.println(input);
       if (input.equalsIgnoreCase(YES))    {
        System.out.println("Quest accepted"); //placeholder
       }
       else if (input.equalsIgnoreCase(NO))    {
        System.out.println("Quest denied"); //placeholder
       }
       break; //placeholder
      case 3:
       System.out.println("You proceed to the next level"); //placeholder
       break;
      default:
       System.out.println("Invalid response");
       System.out.println(0); //test, delete
       break;
     }
   }    
  }
}

Answer 2

You're reading the input with sc.nextInt() . That will choke on inputs like "Yes" or "No". Instead, you should simply read the next line as a string. You can then test whether it is "Yes" or "No" and, if it is neither, you can then try parsing it as an int .