The Double.longValue()
method in Java is used to convert a Double
object to a long
primitive.
Table of Contents
- Introduction
longValue()
Method Syntax- Examples
- Converting a
Double
tolong
- Performing Arithmetic Operations
- Handling
null
Values
- Converting a
- Real-World Use Case
- Conclusion
Introduction
The Double.longValue()
method is an instance method in the Double
class in Java. It converts a Double
object to a long
primitive. This method is useful when you need to narrow down a Double
to a long
for certain operations or storage, bearing in mind that this conversion may lead to loss of precision.
longValue()() Method Syntax
The syntax for the Double.longValue()
method is as follows:
public long longValue()
The method returns:
- The
long
value represented by thisDouble
object.
Examples
Converting a Double
to long
The longValue()
method can be used to convert a Double
object to a long
primitive.
Example
public class DoubleToLongExample {
public static void main(String[] args) {
Double doubleObject = 123.45;
long longValue = doubleObject.longValue();
System.out.println("Long value of 123.45: " + longValue);
}
}
Output:
Long value of 123.45: 123
In this example, the Double
object 123.45
is converted to the long
primitive 123
.
Performing Arithmetic Operations
You can use the longValue()
method to extract the long
primitive from a Double
object and perform arithmetic operations.
Example
public class ArithmeticOperationsExample {
public static void main(String[] args) {
Double doubleObject1 = 50.75;
Double doubleObject2 = 25.25;
long sum = doubleObject1.longValue() + doubleObject2.longValue();
long difference = doubleObject1.longValue() - doubleObject2.longValue();
long product = doubleObject1.longValue() * doubleObject2.longValue();
long quotient = doubleObject1.longValue() / doubleObject2.longValue();
System.out.println("Sum: " + sum);
System.out.println("Difference: " + difference);
System.out.println("Product: " + product);
System.out.println("Quotient: " + quotient);
}
}
Output:
Sum: 75
Difference: 25
Product: 1200
Quotient: 2
In this example, the Double
objects 50.75
and 25.25
are converted to long
primitives, and arithmetic operations are performed on them.
Handling null
Values
When dealing with Double
objects, it’s important to handle null
values to avoid NullPointerException
.
Example
public class NullHandlingExample {
public static void main(String[] args) {
Double doubleObject = null;
if (doubleObject != null) {
long longValue = doubleObject.longValue();
System.out.println("Long value: " + longValue);
} else {
System.out.println("The Double object is null.");
}
}
}
Output:
The Double object is null.
In this example, the code checks if the Double
object is null
before attempting to convert it to a long
primitive.
Real-World Use Case
Converting User Input
In a real-world application, you might need to convert user input, which is often in the form of Double
objects, to long
primitives for calculations.
Example
import java.util.Scanner;
public class UserInputExample {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("Enter a number: ");
Double doubleObject = scanner.nextDouble();
long longValue = doubleObject.longValue();
long result = longValue * 2;
System.out.println("The result of doubling the input is: " + result);
scanner.close();
}
}
Output (example input 12.34):
Enter a number:
The result of doubling the input is: 24
In this example, the user input is read as a Double
object and then converted to a long
primitive for a calculation.
Conclusion
The Double.longValue()
method in Java is a straightforward way to convert Double
objects to long
primitives. By understanding how to use this method, you can efficiently handle tasks that involve converting Double
objects to long
primitives in your Java applications. Whether you are performing arithmetic operations, handling user input, or avoiding null
values, the longValue()
method provides a reliable solution for these tasks.