This tutorial will show how to read user input when creating a console application. This is very useful when the program you are writing needs to get input from user before it can proceed with processing.
System.console().readLine()
The simplest way to
read user input is by using System.console(). Here is an example:
public class Sample {
public static void main(String[] args) {
System.out.print("Please enter your
name: ");
String name = System.console().readLine();
System.out.println("Your name is:
" + name);
}
}
And this is a sample conversation with the user when the program is run:
Please enter your name: John
Your name is: John
java.util.Scanner and System.in
Combining System.in
and java.util.Scanner provides a way to read user input that can run inside an
IDE. It also provides a way to read different data types.
read string input:
import java.util.Scanner;
public class Test {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("What is your favorite color? ");
String name = scanner.next();
System.out.println("Your favorite color is: " + name);
}
}
Sample output:
What is your favorite color? blue
Your favorite color is: blue
read
byte input:
import java.util.Scanner;
public class Test {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a small number: ");
byte number = scanner.nextByte();
System.out.println("The number is: " + number);
}
}
Sample output:
Enter a small number: 5
The number is: 5
read short input:
import java.util.Scanner;
public class Test {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a short integer: ");
short number = scanner.nextShort();
System.out.println("The number is: " + number);
}
}
Sample output:
Enter a short integer: 1000
The number is: 1000
read
int input:
import java.util.Scanner;
public class Test {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter an integer: ");
int number = scanner.nextInt();
System.out.println("The number is: " + number);
}
}
Sample output:
Enter an integer: 211555777
The number is: 211555777
read
long input:
import java.util.Scanner;
public class Test {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a long number: ");
long number = scanner.nextLong();
System.out.println("The number is: " + number);
}
}
Sample output:
Enter a long number: 12345678912
The number is: 12345678912
read
float input:
import java.util.Scanner;
public class Test {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a float number: ");
float number = scanner.nextFloat();
System.out.println("The number is: " + number);
}
}
Sample output:
Enter a float number: 1.25
The number is: 1.25
read
double input:
import java.util.Scanner;
public class Test {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a double number: ");
double number = scanner.nextDouble();
System.out.println("The number is: " + number);
}
}
Sample output:
Enter a float number: 55.11
The number is: 55.11
read
boolean input:
import java.util.Scanner;
public class Test {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a boolean value (true or false): ");
boolean bool = scanner.nextBoolean();
System.out.println("You entered: " + bool);
}
}
Sample output:
Enter a boolean value (true or false): true
You entered: true
BufferedReader, InputStreamReader, and System.in
Here is another example of getting user input using
BufferedReader, InputStreamReader, and System.in. This way will also work
inside an IDE.
Example code:
read String input:
read String input:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Test {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Please enter your name? ");
String name = reader.readLine();
System.out.println("Your name is: " + name);
}
}
And the behavior is
the same as the samples above:
Please enter your name? James
Your name is: James
read int input:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Test {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Please enter a Integer value ");
int a=Integer.parseInt(reader.readLine());
System.out.println("Number is: " + a);
}
}
And the behavior is the same as the samples above:
Please enter a Integer value 6
Number is: 6
read float input:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Test {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Please enter a Float value ");
float a=Float.parsefloat(reader.readLine());
System.out.println("Number is: " + a);
}
}
And the behavior is the same as the samples above:
Please enter a Integer value 3.44
Number is: 3.44
read double input:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Test {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Please enter a Double value ");
double a=Double.parsedouble(reader.readLine());
System.out.println("Number is: " + a);
}
}
And the behavior is the same as the samples above:
Please enter a Integer value 45.33333333
Number is: 45.33333333
