Java User Input (Scanner)
Java User Input
The Scanner class is used to get
user input, and it is found in the java.util package.
To use the Scanner class, create an object of the class and use any of the available methods found in the Scanner class documentation.
In our example, we will use the nextLine() method, which is used to read Strings:
Example
import java.util.Scanner; // Import the Scanner class
class MyClass {
public static void main(String[] args) {
Scanner myObj = new Scanner(System.in); // Create a Scanner object
System.out.println("Enter username");
String userName = myObj.nextLine(); // Read user input
System.out.println("Username is: " + userName); // Output user input
}
}
If you don't know what a package is, read our Java Packages Tutorial.
Input Types
In the example above, we used the nextLine() method, which is used to read Strings. To read other types, look at the table below:
| Method | Description |
|---|---|
nextBoolean() |
Reads a boolean value from the user |
nextByte() |
Reads a byte value from the user |
nextDouble() |
Reads a double value from the user |
nextFloat() |
Reads a float value from the user |
nextInt() |
Reads a int value from the user |
nextLine() |
Reads a String value from the user |
nextLong() |
Reads a long value from the user |
nextShort() |
Reads a short value from the user |
In the example below, we use different methods to read data of various types:
Example
import java.util.Scanner;
class MyClass {
public static void main(String[] args) {
Scanner myObj = new Scanner(System.in);
System.out.println("Enter name, age and salary:");
// String input
String name = myObj.nextLine();
// Numerical input
int age = myObj.nextInt();
double salary = myObj.nextDouble();
// Output input by user
System.out.println("Name: " + name);
System.out.println("Age: " + age);
System.out.println("Salary: " + salary);
}
}
Note: If you enter wrong input (e.g. text in a numerical input), you will get an exception/error message (like "InputMismatchException").
You can read more about exceptions and how to handle errors in the Exceptions chapter.
