Java異常處理（用戶輸入中的空白）

Question

我需要創建一個異常類，當用戶輸入的名稱，密碼等（所有字符串）中有空格時，該異常類將引發異常。 我已經寫了所有我認為必要的代碼，無論輸入什么，總是會拋出異常。

我究竟做錯了什么？

以下是代碼片段。 如果需要整個程序，請告訴我。

EmptyInputException類：

public class EmptyInputException extends Exception{
public EmptyInputException(){
    super("ERROR: Spaces entered - try again.");
}
public EmptyInputException(String npr){
    super("ERROR: Spaces entered for " + npr + " - Please try again.");
}

}

這是我捕獲異常的getInput方法：

 public void getInput() {
    boolean keepGoing = true;

    System.out.print("Enter Name: ");

    while (keepGoing) {

            if(name.equalsIgnoreCase("Admin")){
            System.exit(1);
            }else

        try {
            name = scanner.next();
            keepGoing = false;
            throw new EmptyInputException();

        } catch (EmptyInputException e) {
            System.out.println("ERROR: Please do not enter spaces.");
            keepGoing = true;
        }//end loop
    }
    System.out.print("Enter Room No.:");

    while (keepGoing) {
        if(room.equalsIgnoreCase("X123")){
            System.exit(1);
        }else
        try {
            room = scanner.next();
            if (room.contains(" ")){
                throw new EmptyInputException();
            }else
                keepGoing = false;

        } catch (EmptyInputException e) {
            System.out.println("ERROR: Please do not enter spaces.");
            keepGoing = true;
        }
    }

    System.out.print("Enter Password:");

    while (keepGoing) {
        if(pwd.equals("$maTrix%TwO$")){
            System.exit(1);
        }else
        try {
            pwd = scanner.next();
            keepGoing = false;
            throw new EmptyInputException();
        } catch (EmptyInputException e) {
            System.out.println("ERROR: Please do not enter spaces.");
            keepGoing = true;
        }
    }

}

我感覺好像丟失了掃描儀輸入中應該包含空格的部分，例如：

if(name.contains(" "))

等等...

到目前為止，我的輸出（例如，輸入名稱后）將顯示Error: Please do not put spaces.

Answer 1

try {
        name = scanner.next();
        keepGoing = false;
        if(name.contains(" "))
            throw new EmptyInputException();

    }

應該做到這一點嗎？

Answer 2

你的猜測是對的。

    try {
        name = scanner.next();
        keepGoing = false;
        throw new EmptyInputException(); // You're always going to throw an Exception here.

    } catch (EmptyInputException e) {
        System.out.println("ERROR: Please do not enter spaces.");
        keepGoing = true;
    }

可能是粗心的錯誤。 需要一個if(name.contains(" ")) ：D您的密碼塊發生了同樣的事情。