Java Convert String to long examples

In this tutorial, we will see how to convert String to long in Java.There are three ways to convert a String to a long value.

1. Java – Convert String to long using Long.parseLong(String)

Long.parseLong(String): All the characters in the String must be digits except the first character, which can be a digit or a minus ‘-‘. For example – long var = Long.parseInt("-123"); is allowed and the value of var after conversion would be -123.

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

In this example, the string str2 has minus sign ‘-‘ in the beginning, which is why the the value of variable num2 is negative.

public class Example {
   public static void main(String[] args)
   {
       String str = "21111";
       String str2 = "-11111";
       //Conversion using parseLong(String) method
       long num = Long.parseLong(str);
       long num2 = Long.parseLong(str2);
       System.out.println(num+num2);		
   }
}

Output:

10000

2. Java – Convert String to long using Long.valueOf(String)

Long.valueOf(String): Converts the String to a long value. Similar to parseLong(String) method, this method also allows minus ‘-‘ as a first character in the String.

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

public class Example {
   public static void main(String[] args)
   {
       String str = "11111";
       String str2 = "88888";
       //Conversion using valueOf(String) method
       long num = Long.valueOf(str);
       long num2 = Long.valueOf(str2);
       System.out.println(num+num2);		
   }
}

Output:

99999

3. Java – Convert String to long using the constructor of Long class

Long(String s) constructor : Long class has a constructor which allows String argument and creates a new Long object representing the specified string in the equivalent long value. The string is converted to a long value in exactly the manner used by the parseLong(String) method for radix 10.

Java Program for String to long conversion using new Long(String)

public class Example {
   public static void main(String[] args)
   {
       String str = "10000";
       String str2 = "22222";
       //Conversion using Long(String s) constructor
       long num = new Long(str);
       long num2 = new Long(str2);
       System.out.println(num*num2);		
   }
}

Output:

222220000

Related Posts:

1. Java – Convert long to String examples
2. Java – Convert char to String and vice versa
3. Java – Convert char array to String examples
4. Java – Convert String to int examples