- Java Introduction
- Java Getting Started
- Java Syntax
- Java Comments
- Java Variables
- Java Data Types
- Java Type Casting
- Java Operators
- Java Strings
- Java Math
- Java Booleans
- Java If ... Else
- Java Switch
- Java While Loop
- Java For Loop
- Java Break And Continue
- Java Arrays
- Java Methods
- Java Method Parameters
- Java Method Overloading
- Java Scope
- Java Recursion
- Java OOP
- Java Classes And Objects
- Java Class Attributes
- Java Class Methods
- Java Constructors
- Java Modifiers
- Java Encapsulation
- Java Packages
- Java Inheritance
- Java Polymorphism
- Java Inner Classes
- Java Abstraction
- Java Interface
- Java Enums
- Java User Input (Scanner)
- Java Date And Time
- Java ArrayList
- Java LinkedList
- Java HashMap
- Java HashSet
- Java Iterator
- Java Wrapper Classes
- Java Exceptions - Try...Catch
- Java Regular Expressions
- Java Threads
- Java Lambda Expressions
- Java Files
- Java Create And Write To Files
- Java Read Files
- Java Delete Files
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 Main {
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
}
}
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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 Main {
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.
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