Java Program to Convert String to Long

To convert a String to Long in Java, we can use built-in methods provided by the Long class. In this article, we will learn how to convert String to Long in Java with different methods.  

Example:

In the below example, we use the most common method i.e. Long.parseLong() method to convert a string to a primitive long.

// Java Program to convert String to Long using parseLong() Method public class GFG {  public static void main(String args[]) {    // Creating a custom string  String s = "999999999999";  System.out.println("String: " + s);  // Converting into Long  long l = Long.parseLong(s);  // Printing String as Long  System.out.println("Long: " + l);  } } 

String: 999999999999 Long: 999999999999 

Note: 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 of Long.parseLong() method

Long varLong = Long.parseLong(s);

Parameter:

• str: A string containing numeric characters. It can include a leading "-" for negatives.

Return Type:

• A long primitive representing the numeric value of the string.

Other Methods to Convert String to Long in Java

There are many other ways to convert a String to a Long data type in Java which are as follows:

1. Using Long.valueOf() Method

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 of Long.valueOf() Method

long varLong = Long.valueOf(str);

Example:

// Java Program to Convert String to Longn using valueOf() Method public class GFG {  public static void main(String args[])  {    // Creating custom string  String s = "999999999999";  // Printing the above string  System.out.println("String - " + s);  // Converting into Long data type  long l = Long.valueOf(s);  // Printing String as Long  System.out.println("Long - " + l);  } } 

String - 999999999999 Long - 999999999999 

2. 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. 

Example:

// Java Program to Convert String to Long using Constructor of Long class import java.io.*; import java.util.*; class GFG {  public static void main(String[] args)  {    // Custom input string  String s = "999999999";  System.out.println("String - " + s);  // Converting above string to long  // using Long(String s) constructor  long n = new Long(s);  // Printing the above long value  System.out.println("Long - " + n);  } } 

String - 999999999 Long - 999999999 

Note: The Long(String s) constructor is deprecated since Java 9. It is recommended to use Long.parseLong() or Long.valueOf() for converting a String to long.