Java初学者代码片段帮助。代码不工作？

Question

我目前正在编写一个简单的java文本游戏，你会用摇滚剪刀在电脑上玩电脑。

我无法弄清楚为什么我的代码无法正常工作。我确定我做了一些愚蠢的事情。请帮忙。

        System.out.println("Welcome to rock paper scissors! select 'Rock', 'Paper', or 'Scissors'");

    Scanner scan = new Scanner(System.in);

    while(playerscore <2 && computerscore <2 ){
        String player = scan.next();
        System.out.println("you chose "+player+".");

        //convert lowercase to capital
        if(player.equals("rock")){      
            player = "Rock";
        }
        else if(player.equals("paper")){
            player = "Paper";
        }
        else if(player.equals("scissors")){
            player = "Scissors";
        }

        Random ran = new Random();
        int computer = ran.nextInt(3);

        if(computer == 0){
            System.out.println("Computer chose rock.");
            if(player.equals("Rock")) {
                tie();
            }
            else if (player.equals("Paper")){
                lose();
            }
            else if(player.equals("Scissors")){
                win();
            }

        }
        else if(computer == 1){
            System.out.println("Computer chose paper.");
            if(player.equals("Rock")){
                win();
            }
            else if (player.equals("Paper")){
                tie();
            }
            else if(player.equals("Scissors")){
                lose();
            }}

        else if(computer == 2){
            System.out.println("Computer chose paper.");
            if(player.equals("Rock")){
                lose();
            }
            else if (player == "Paper"){
                win();
            }
            else if(player.equals("Scissors")){
                tie();
            }}
        }


        }



public static int playerscore = 0;
public static int computerscore = 0;

public static void tie(){
    System.out.println("You and the computer tied!");
    return;

}
public static void win(){
    System.out.println("You won that round!");
    playerscore++;
    System.out.println("you now have "+playerscore+" points");
    return;
}
public static void lose(){
    System.out.println("You lost that round!");
    computerscore++;
    System.out.println("The computer now has "+ computerscore + " points");
}

`