Java 为什么输入后我的程序没有打印出来？

好的，我正在用java制作一个石头剪刀程序，我有所有的代码，它应该会给我想要的输出，但每次我运行它时，它只打印出输入语句，其他什么都没有。我让它在do循环之后打印一行，输入语句所在的位置，然后打印出来，但它不打印if语句中的任何内容，我不太明白为什么。这就是我所拥有的。谢谢你提供的任何帮助

public static void main(String[] args) 
{
    Scanner input = new Scanner(System.in);
    Random rand = new Random();

    String replay = ("");
    String user = ("");
    int ai = 0;
    String aiPlay = ("");

    do
    {
        ai = rand.nextInt(3) + 1;

        switch (ai)    //was if statements but java suggested to change to switch statements
        {
            case 1:
                aiPlay = ("Rock");
                break;
            case 2:
                aiPlay = ("Paper");
                break;
            default:
                aiPlay = ("Scissors");
                break;
        }

        do   //make sure input is correct
        {
            System.out.print("rock, paper, or scissors: ");
            user = input.next();
        }while(!(user.equals("rock") || user.equals("paper") || user.equals("scissors")));

        if(user.equals(ai))
        {
        System.out.println("You played " + user + ".\nThe computer player " + aiPlay + ".\nIt was a tie!");
        System.out.print("Continue? (y or n): ");
        replay = input.next();
        }
        switch (user) {    //was if statements java suggested it change to switch statement 
            case "rock":
                if (aiPlay.equals("scissors"))
                {
                    System.out.println("You played " + user + ".\nThe computer player " + aiPlay + ".\nYou win!");
                    System.out.print("Continue? (y or n): ");
                    replay = input.next();
                }

                else if (aiPlay.equals("paper"))
                {
                    System.out.println("You played " + user + ".\nThe computer player " + aiPlay + ".\nYou lose!");
                    System.out.print("Continue? (y or n): ");
                    replay = input.next();
                }   break;
            case "paper":
                if (aiPlay.equals("scissors"))
                {
                    System.out.println("You played " + user + ".\nThe computer player " + aiPlay + ".\nYou win!");
                    System.out.print("Continue? (y or n): ");
                    replay = input.next();
                }

                else if (aiPlay.equals("rock"))
                {
                    System.out.println("You played " + user + ".\nThe computer player " + aiPlay + ".\nYou lose!");
                    System.out.print("Continue? (y or n): ");
                    replay = input.next();
                }   break;
            case "scissors":
                if (aiPlay.equals("paper"))
                {
                    System.out.println("You played " + user + ".\nThe computer player " + aiPlay + ".\nYou win!");
                    System.out.print("Continue? (y or n): ");
                    replay = input.next();
                }

                else if (aiPlay.equals("rock"))
                {
                    System.out.println("You played " + user + ".\nThe computer player " + aiPlay + ".\nYou lose!");
                    System.out.print("Continue? (y or n): ");
                    replay = input.next();
                }   break;
            default:
                break;
        }

    }while(replay.equals("y"));
}

---

使调试和读取程序更容易的提示：将请求重播的代码从switch语句中移出（最好移到循环的末尾），因为它总是相同的。还可以查看这些行：

aiPlay=（“Rock”）

和

aiPlay.equals（“Rock”）

-看到问题了吗？因此，AI执行“Rock”、“Paper”或“剪刀”，而用户执行“Rock”、“Paper”或“剪刀”。这些选择中有任何一个是平等的吗？谢谢你，克里斯。我看了所有的东西，想弄明白为什么它刚刚结束。我只是忘了大写字母和ai的关系。非常感谢。

switch (ai)    //was if statements but java suggested to change to switch 
statements
    {
        case 1:
            aiPlay = ("rock"); /* All should be lowercase*/ 
            break;
        case 2:
            aiPlay = ("paper"); /* All should be lowercase*/ 
            break;
        default:
            aiPlay = ("scissors"); /* All should be lowercase*/ 
            break;
    }