为什么我输入的每一个输入都忽略While循环？

Question

package rockPaperScissors;
import java.util.*

public class RockPaperScissors {
    public static final int quit = 0;
    public static final int rock = 1;
    public static final int paper = 2;
    public static final int scissors = 3;
    static Scanner console = new Scanner(System.in);

public static void main(String [] args) {
    //gets userHand from user as int
    int userHand = promptUserForHand();
    while(userHand != quit) {
        //gets computerHand from the computer(random) as int
        int computerHand = generateRandomHand();
        //compares userHand to computerHand, determines the winner
        String winner = determineWinner(userHand, computerHand);
        //prints out the winner
        System.out.println("The winner is the: " + winner);
        //starts the next round
        userHand = promptUserForHand();
    }
    //if userHand equals quit, stop program and say goodbye
    if(userHand == quit) {
        System.out.println("Goodbye!!!");
        console.close();        
    }
}

public static int promptUserForHand() {
    //gets userInput from user
    System.out.println("Please input either rock, paper, scissors (or enter quit to stop)");
    String userInput = console.next(); 
    //converts String into int, so userHand and computerHand can be compared
    int userHand = 0;
    if(userInput == "rock" || userInput == "Rock" || userInput == "r") {
        userHand  = rock;
    }
    else if(userInput == "paper" || userInput == "Paper" || userInput == "p") {
        userHand = paper;
    }
    else if(userInput == "scissors" || userInput == "Scissors" || userInput == "s"){
        userHand = scissors;
    }
    else {
        userHand = quit;
    }
    return userHand;
}

//generates computerHand from computer(randomly chooses either rock(1), paper(2), or scissors(3))
public static int generateRandomHand() {
    Random r = new Random();
    int computerHand = r.nextInt(4) + 1;
    return computerHand;
}

//compares userHand to computerHand to determine the winner
public static String determineWinner(int userHand, int computerHand) {
    String winner = " ";
    if(userHand == 1 && computerHand == 2) {
        winner = "Computer!!!";
    }
    else if(userHand == 1 && computerHand == 3) {
        winner = "User!!!";
    }
    else if(userHand == 2 && computerHand == 1) {
        winner = "User!!!";
    }
    else if(userHand == 2 && computerHand == 3) {
        winner = "Computer!!!";
    }
    else if(userHand == 3 && computerHand == 1) {
        winner = "Computer!!!";
    }
    else if(userHand == 3 && computerHand == 2) {
        winner = "User!!!";
    }
    else {
        winner = "Tie!!!";
    }       
    return winner;
}

Answer 1

在Java中，不应该使用==来比较字符串。请使用:equals()或equalsignorecase()方法。

例如：

而不是：

 if(userInput == "rock" || userInput == "Rock" || userInput == "r") 

if(userInput.equalsIgnoreCase("rock") || userInput.equalsIgnoreCase("r"))