Java hasNextLine(), nextLine without giving file

Asked Jun 10 '21 at 18:27

Active Jun 10 '21 at 18:36

Viewed 53 times

I have program that gets file java program < file.txt and i want to make exception for case when user dont give an file input just: java program but I couldnt find any exception for that and when I am trying to check it with

Scanner input = new Scanner(System.in);
String tmp;
    try {
        tmp = input.nextLine();
    }
    catch(Exception e){
        return 0;
    }

nothing happens.

edited Jun 10 '21 at 18:36

asked Jun 10 '21 at 18:27

sadge_user

`throw new IllegalArgumentException(“Expected ‘java program’”);`? If that’s not sufficient you can make your own `Exception` subclass by extending it. – BeUndead Jun 10 '21 at 18:31
The problem is it goes to the try but then stops, program dont end but its just stopping and nothing is happening – sadge_user Jun 10 '21 at 18:35
1

Any reason for using the "<" for reading the file? – Stefan Freitag Jun 10 '21 at 18:45
1

@sadge_user: it’s scanning for input. It won’t continue until it gets some. Are you meaning you want a timeout if someone doesn’t provide any input at all? – BeUndead Jun 10 '21 at 18:51
@BeUndead yes, I want to exit program if user doesnt provide any input – sadge_user Jun 10 '21 at 18:54
Then [that’s been asked before](https://stackoverflow.com/a/61843625/2478398) – BeUndead Jun 10 '21 at 19:29

Java hasNextLine(), nextLine without giving file

0 Answers0