Java Program to Convert String to Long

In this article, we will be performing String to Long Conversion with different methods.

Illustration of the Conversion String to Long

Input : String = “20”
Output : 20

Input : String = “999999999999”
Output : 999999999999

Methods to Convert String to Long

There are many methods for converting a String to a Long data type in Java which are as follows:

1. Using the parseLong() method of the Long class 
2. Using valueOf() method of long class 
3. Using the constructor of the Long class

1. Using Long.parseLong() method of Long Class 

Long.parseLong() method is a method in which all the characters in the String must be digits except the first character, which can be a digit or a minus ‘-‘. 

Syntax

Long varLong=Long.parseLong(str);

Java Program to Convert String to Long using Long.parseLong() Method

Java

// Java Program to convert String to Long
// using parseLong() Method

// Class
public class GFG {

    // Main driver method
    public static void main(String args[])
    {
        // Creating a custom string
        String str = "999999999999";
        System.out.println("String - " + str);

        // Converting into Long
        long varLong = Long.parseLong(str);

        // Printing String as Long
        System.out.println("Long - " + varLong);
    }
}

Output

String - 999999999999
Long - 999999999999

2. Using valueOf() Method of Long Class 

The valueOf() method of the Long class is a method that converts the String to a long value. Similar to parseLong(String) method, this method also allows minus ‘-‘ as a first character in the String.

Syntax

long varLong = Long.valueOf(str);

Java Program to Convert String to Long using Long.valueOf() Method

Java

// Java Program to Convert String to Long
// Using valueOf() Method

// Class
public class GFG {

    // Main driver method
    public static void main(String args[])
    {
        // Creating custom string
        String str = "999999999999";

        // Printing the above string
        System.out.println("String - " + str);

        // Converting into Long data type
        long varLong = Long.valueOf(str);

        // Printing String as Long
        System.out.println("Long - " + varLong);
    }
}

Output

String - 999999999999
Long - 999999999999

3. Using Constructor of Long Class

The Long class has a constructor which allows the String argument and creates a new Long object representing the specified string in the equivalent long value. 

Java Program to Convert String to Long using Constructor of Long Class

Java

// Java Program to Convert String to Long
// Using Constructor of Long class

// Importing required classes
import java.io.*;
import java.util.*;

// Class
class GFG {

    // Main driver method
    public static void main(String[] args)
    {
        // Custom input string
        String str = "999999999";
        System.out.println("String - " + str);

        // Converting above string to long
        // using Long(String s) constructor
        long num = new Long(str);

        // Printing the above long value
        System.out.println("Long - " + num);
    }
}

Output