java - 在我可以解析用户的输入之前，IDE 会打印这两行

Question

所以我目前很难解决这个问题。简而言之，我正在尝试为类(class)创建一个银行应用程序。我正在编写一种方法来打印并获取用户的输入，但打印行会在我获取输入之前打印出两行。这是我的实现。

boolean done = false; 
        while(!done) {
            System.out.println("Welcome to Running Bank"
                        + "\nWhat would you like to do?"
                        + "\n1-Create Account"
                        + "\n2-Log-In"
                        + "\n3-Exit");
            choice = scanner.nextInt();
            switch(choice) {
            case 1:
                System.out.println("Input your username(No more than 15 characters: ");
                Username = scanner.nextLine();
                System.out.println("Input your password(Must be at least 8 characters and not over 24): ");
                Password = scanner.nextLine();
        }
    }
}

我期望它做的是打印出“输入您的用户名”，然后在获得用户的输入后打印下一行。然而，现在发生的事情是，在我输入任何内容之前，这两行都已打印出来。提前谢谢您。

Answer 1

boolean done = false; 
        while(!done) {
            System.out.println("Welcome to Running Bank"
                        + "\nWhat would you like to do?"
                        + "\n1-Create Account"
                        + "\n2-Log-In"
                        + "\n3-Exit");
            choice = scanner.nextInt();
            scanner.nextLine();
            switch(choice) {
            case 1:
                System.out.println("Input your username(No more than 15 characters: ");
                Username = scanner.nextLine();
                System.out.println("Input your password(Must be at least 8 characters and not over 24): ");
                Password = scanner.nextLine();
        }
    }
}

现在应该可以了。我在输入choice

后添加了一个 scanner.nextLine()