How to get input from user in Java from command line or console is one of the common thing
,every one started learning Java looks for. It’s second most popular way of
starting programming after HelloWorld
in Java. There are so many ways to get input from User in Java including
command line and Graphical user interface. For beginner simpler the example,
better it is. first and foremost way of getting input from user is String[]
passed to main
method in Java but that only work for one time requirement and its not
interactive. Another way of getting input from User is involving IO classes
like InputStream
to read from console or command line which can be little complicated for true
beginner. Thanks to Java 5 which added a nice utility class called Scanner, has made
task of getting input from user very easy. Scanner is
powerful and allows you to get any kind of input from User e.g. String,
int,
float etc.
On the other hand if you are looking to use a GUI for getting input from
user than best option is to use JOptionPane. JOptionPane allows you
to show dialog box and get input from user without all the hassles of Swing API,
which is also a popular Java
Swing Interview question.By the way In this Java Program we will see both Scanner and JOptionPane to get
input from User.
Code
Example
Here is complete code example of Java Program to get input from userinteractively. This Java Program uses java.util.Scanner to
get String,
int and float as input from User and then finally display a dialog box using JOptionPane to get
input from User. you can use any approach as per your need.
/**
* Simple Java program to get Input from User. Shows two examples
to get input from
* command line and getting input
using GUI screen by using JOptionPane.
* Scanner class can be used to
get different kind of input from User
* e.g. String, int, char, float
and double.
*
* JOptionPane has static utility method which can display dialog boxes and
ask
* user to enter input, a much
interactive way of getting input from User.
* JOptionPane returns user
entered value as String which can then be converted
* to number by using
Integer.parseInt or Float.parseFloat() etc.
*
* @author Javarevisited
*/
public class
InputFromUser {
public static void
main(String args[])
throws IOException {
//Java Exmaple to
get input from user from command prompt
System.out.println("Please enter input from command prompt: ");
Scanner inputReader = new Scanner(System.in);
//Getting input in String format
String
name = inputReader.nextLine();
System.out.println("Hi " + name);
//Getting number as
input from command line in Java
System.out.println("Please enter a number from command line? ");
int
number = inputReader.nextInt();
System.out.println("You have entered : " + number);
//Getting floating
point as input from command line in Java
System.out.println("Please enter a floating point number from command
line? ");
float
decimal = inputReader.nextFloat();
System.out.println("You have entered : " + decimal);
//Java Example to
get input from user using GUI
String input = JOptionPane.showInputDialog("Enter any number of your choice");
System.out.println("User has entered: " + input);
}
}
Output:
Please enter input from command prompt:
Java Programming tutorial
Hi Java Programming tutorial
Please enter a number from command line?
22
You have entered : 22
Please enter a floating point number from command line?
22.34
You have entered : 22.34
User has entered: 34343
That's all on how to get input from user in Java. I have already
discussed many other ways to get input from command
line in my post 5 example to get input from Console. Overall Java has
excellent support for getting input from user which allows Java programmers at
beginner level to write simple program driven from User input.
Other Java Beginners tutorials from Javarevisited Blog
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