为什么我的异常不会打印出它的打印语句？ (爪哇)

Question

The print statement in my exception never prints out. If I do not enter anything it will just continue to ask me to enter name of cruise ship. I need it to throw the exception print statement along with that if someone were to enter an empty string or anything other than a string.

 do {
  try {
      System.out.println("Enter name of cruise ship: ");
      cruiseShipName = scnr.nextLine();

      }
  catch(Exception e){
      e.printStackTrace();
        System.out.println("Invalid Input. Please try again.");
    }
} while (cruiseShipName.equals(""));

Answer 1

Maybe your code will not throw any exception if the scnr.nextLine() is empty.

In your case if you want to ask the user to try again, you could do as following:

`

do {
    System.out.println("Enter name of cruise ship: ");
    cruiseShipName = scnr.nextLine();
    if (cruiseShipName.equals("")) {
        System.out.println("Invalid Input. Please try again.");
    }
} while (cruiseShipName.equals(""));

`

Answer 2

The may help you.

do {
  try {
      System.out.println("Enter name of cruise ship: ");
      cruiseShipName = scnr.nextLine();
      if(cruiseShipName.equals("")) throw new Exception("");
      }
  catch(Exception e){
      e.printStackTrace();
        System.out.println("Invalid Input. Please try again.");
    }
} while (cruiseShipName.equals(""));

Answer 3

This code doesn't actually throw an exception. You don't have anything that checks if the input is valid and throws an exception if it isn't.

So right now, the input is always valid.

Answer 4

The print statement in my exception never prints out. If I do not enter anything it will just continue to ask me to enter name of cruise ship. I need it to throw the exception print statement along with that if someone were to enter an empty string or anything other than a string.

 do {
  try {
      System.out.println("Enter name of cruise ship: ");
      cruiseShipName = scnr.nextLine();

      }
  catch(Exception e){
      e.printStackTrace();
        System.out.println("Invalid Input. Please try again.");
    }
} while (cruiseShipName.equals(""));