Java Long valueOf() Method

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The Long.valueOf() method in Java is used to convert a long primitive or a String to a Long object. This method has multiple versions to handle different use cases, including converting a string representation of a number in a specified radix (base) to a Long object.

Table of Contents

1. Introduction
2. valueOf() Method Syntax
3. Overloaded Versions
   • valueOf(long l)
   • valueOf(String s)
   • valueOf(String s, int radix)
4. Examples
   • Converting a long to Long
   • Converting a String to Long
   • Converting a String with a Radix to Long
5. Real-World Use Case
6. Conclusion

Introduction

The Long.valueOf() method is a static method in the Long class in Java. It converts primitive long values and String representations of numbers into Long objects. This method is useful when you need to work with Long objects instead of primitive long values, such as when working with collections or APIs that require objects.

valueOf()() Method Syntax

There are three primary overloaded versions of the valueOf() method in the Long class:

1. public static Long valueOf(long l)
2. public static Long valueOf(String s) throws NumberFormatException
3. public static Long valueOf(String s, int radix) throws NumberFormatException

Overloaded Versions

1. valueOf(long l)

This method converts the primitive long value l to a Long object.

public static Long valueOf(long l)

• l: The long value to be converted to a Long object.

The method returns:

• A Long object representing the specified long value.

2. valueOf(String s)

This method converts the string s to a Long object.

public static Long valueOf(String s) throws NumberFormatException

• s: The string to be converted to a Long object.

The method returns:

• A Long object representing the value of the specified string.

Throws:

• NumberFormatException if the string does not contain a parsable long.

3. valueOf(String s, int radix)

This method converts the string s to a Long object using the specified radix.

public static Long valueOf(String s, int radix) throws NumberFormatException

• s: The string to be converted to a Long object.
• radix: The radix to be used in interpreting the string.

The method returns:

• A Long object representing the value of the specified string in the specified radix.

Throws:

• NumberFormatException if the string does not contain a parsable long.

Examples

Converting a long to Long

The valueOf(long l) method converts a primitive long to a Long object.

Example

public class ValueOfLongExample {
    public static void main(String[] args) {
        long number = 123456789L;
        Long longObject = Long.valueOf(number);

        System.out.println("Long object: " + longObject);
    }
}

Output:

Long object: 123456789

In this example, the primitive long 123456789L is converted to a Long object.

Converting a String to Long

The valueOf(String s) method converts a string to a Long object.

Example

public class ValueOfStringExample {
    public static void main(String[] args) {
        String numberString = "987654321";
        Long longObject = Long.valueOf(numberString);

        System.out.println("Long object: " + longObject);
    }
}

Output:

Long object: 987654321

In this example, the string "987654321" is converted to a Long object.

Converting a String with a Radix to Long

The valueOf(String s, int radix) method converts a string in a specified radix to a Long object.

Example

public class ValueOfStringWithRadixExample {
    public static void main(String[] args) {
        String binaryString = "11111111";
        Long longObject = Long.valueOf(binaryString, 2);

        System.out.println("Long object (binary): " + longObject);

        String hexString = "7FFFFFFFFFFFFFFF";
        longObject = Long.valueOf(hexString, 16);

        System.out.println("Long object (hexadecimal): " + longObject);
    }
}

Output:

Long object (binary): 255
Long object (hexadecimal): 9223372036854775807

In this example, the binary string "11111111" is converted to the long value 255, and the hexadecimal string "7FFFFFFFFFFFFFFF" is converted to the long value 9223372036854775807.

Real-World Use Case

Parsing Configuration Values

In a real-world application, you might use the Long.valueOf() method to parse configuration values from a properties file or environment variables.

Example

import java.util.Properties;

public class ConfigurationExample {
    public static void main(String[] args) {
        Properties properties = new Properties();
        properties.setProperty("maxConnections", "1000");
        properties.setProperty("timeout", "5000");

        Long maxConnections = Long.valueOf(properties.getProperty("maxConnections"));
        Long timeout = Long.valueOf(properties.getProperty("timeout"));

        System.out.println("Max Connections: " + maxConnections);
        System.out.println("Timeout: " + timeout);
    }
}

Output:

Max Connections: 1000
Timeout: 5000

In this example, the configuration values are parsed from a properties file and converted to Long objects using the Long.valueOf() method.

Conclusion

The Long.valueOf() method in Java is a versatile tool for converting long values and String representations of numbers into Long objects. By understanding how to use the different overloaded versions of this method, you can efficiently handle tasks that involve creating and working with Long objects in your Java applications. Whether you are dealing with base 10, different numeral systems, or parsing configuration values, the valueOf() method provides a reliable solution for these tasks.