Convert String To Long in Java

Introduction

Converting a String to a Long in Java is a common task that can be useful in various scenarios such as parsing user input, reading data from files, or handling configuration parameters. In Java, this conversion can be done using several methods. This blog post will explore different methods to convert a String to a Long in Java.

Table of Contents

1. Using Long.parseLong()
2. Using Long.valueOf()
3. Complete Example Program
4. Conclusion

1. Using Long.parseLong()

The Long.parseLong() method parses the string argument as a signed decimal long.

Example:

public class StringToLongUsingParseLong {
    public static void main(String[] args) {
        String strValue = "123456789";

        // Convert string to long using Long.parseLong()
        long longValue = Long.parseLong(strValue);

        System.out.println("String value: " + strValue);
        System.out.println("Long value: " + longValue);
    }
}

Output:

String value: 123456789
Long value: 123456789

Explanation:

• Long.parseLong(strValue) converts the string value to its long representation.

2. Using Long.valueOf()

The Long.valueOf() method returns a Long instance representing the specified string value. This method can also be used to convert a String to a long.

Example:

public class StringToLongUsingValueOf {
    public static void main(String[] args) {
        String strValue = "987654321";

        // Convert string to long using Long.valueOf()
        long longValue = Long.valueOf(strValue);

        System.out.println("String value: " + strValue);
        System.out.println("Long value: " + longValue);
    }
}

Output:

String value: 987654321
Long value: 987654321

Explanation:

• Long.valueOf(strValue) converts the string value to its long representation.

3. Complete Example Program

Here is a complete program that demonstrates both methods discussed above to convert a String to a Long.

Example Code:

public class StringToLongExample {
    public static void main(String[] args) {
        String strValue1 = "123456789";
        String strValue2 = "987654321";

        // Using Long.parseLong() Method
        long longValue1 = Long.parseLong(strValue1);
        System.out.println("Using Long.parseLong():");
        System.out.println("String value: " + strValue1 + " -> Long value: " + longValue1);

        // Using Long.valueOf() Method
        long longValue2 = Long.valueOf(strValue2);
        System.out.println("\nUsing Long.valueOf():");
        System.out.println("String value: " + strValue2 + " -> Long value: " + longValue2);
    }
}

Output:

Using Long.parseLong():
String value: 123456789 -> Long value: 123456789

Using Long.valueOf():
String value: 987654321 -> Long value: 987654321

4. Conclusion

Converting a String to a Long in Java can be accomplished in several ways. The Long.parseLong() and Long.valueOf() methods are both straightforward and widely used. By understanding these different methods, you can choose the one that best fits your needs and coding style.

Happy coding!