如果輸入不正確，我需要重新輸入，我該怎么做？public static void main(String[] args) throws InterruptedException { String welcomeMessage = "Welcome to our system! Please enter your details to log in.\n"; System.out.println(welcomeMessage); TimeUnit.SECONDS.sleep(3); Scanner inputUserName = new Scanner(System.in); String userName = "User Name: "; System.out.println(userName); String userNameInput = inputUserName.nextLine(); while (true) { if (userNameInput.contains("@")) { System.out.println("Shap"); break; } else { System.out.println("\nPlease enter a valid user name!"); String enterAgain = userName; System.out.println(enterAgain); } } }
2 回答
隔江千里
TA貢獻1906條經驗 獲得超10個贊
嘗試在 while 條件中使用它
Scanner inputUserName = new Scanner(System.in);
String userNameInput = inputUserName.nextLine();
while (!userNameInput.contains("@"))
{
System.out.println("\nPlease enter a valid user name!");
userNameInput = inputUserName.nextLine();
}
System.out.println("Success");
慕哥6287543
TA貢獻1831條經驗 獲得超10個贊
您可以通過使用 while 循環來做到這一點 -
Scanner inputUserName = new Scanner(System.in);
String userName = "User Name: ";
System.out.println(userName);
String userNameInput = inputUserName.nextLine();
while (!userNameInput.contains("@"))
{
System.out.println("\nPlease enter a valid user name!");
System.out.println(userName);
userNameInput = inputUserName.nextLine()
}
}
System.out.println("Shap");
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