用户输入时执行Do-While循环-检查输入是否为空或int（java）

Question

I want the user to be repeatedly asked a question if the user input is either empty OR not an int. This is what I have so far:

        Scanner scn = new Scanner(System.in);
        do {
            System.out.print("Enter id: ");
            int id = scn.nextInt();
         } while (!scn.hasNextInt());

Answer 1

简单地说：

while (scanner.hasNextInt());

Answer 2

Try something like this:

boolean running = true;

while(running){
    String s = scn.nextLine();
    if(!(s!=""||isInt(s))){
        running = false;
    }
}

You need to implement your own isInt() function, but some google will give you this.

Answer 3

Try this removing ! :

while (scn.hasNextInt());