Using a scanner across multiple classes in Java?

Question

I have a program in Java that needs to get user input from the console at multiple points across multiple classes. I tried using a scanner in each class but when I close one scanner it closes system.in so I want to use the same scanner across the whole program. I open the scanner in the main class but how do I use the same scanner in other classes?

Or you could not pipe system.in into the scanner at all. Just pass the input to the Scanner as a String. — Nathan
– Nathan, Commented Feb 19, 2014 at 17:32
Why are you closing the Scanners anyway, knowing that it closes the standard input? — Bhesh Gurung
– Bhesh Gurung, Commented Feb 19, 2014 at 17:45
I thought it was just good practice to close all the resources you use? — Birdfriender
– Birdfriender, Commented Feb 19, 2014 at 21:12

Wasif Hossain · Accepted Answer · 2014-02-19 17:36:57Z

2

You have to inject the scanner instance to other classes through constructor. Like below:

import java.util.*;

public class Test1
{
    private Scanner _scanner;

    public Test1(Scanner sc)
    {
        _scanner = sc;
    }
}

public class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        Test1 testObj = new Test1(sc);
    }
}

answered Feb 19, 2014 at 17:36

Wasif Hossain

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Comments

Wasif Hossain · Accepted Answer · 2014-02-19 17:54:49Z

0

import java.util.Scanner;

public class ScannerSaver 
{
    private Scanner scan;

    public ScannerSaver(Scanner s)
    {
        this.scan = s;
    }
}

Simply pass the scanner in as a parameter.

edited Feb 19, 2014 at 17:54

Wasif Hossain

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answered Feb 19, 2014 at 17:40

Aaron Srun

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