Introduction:

In Java programming, there are often scenarios where you need to convert a string representation of a number to its corresponding long value. While it may seem like a straightforward task, choosing the right strategy for string-to-long conversion can have a significant impact on performance and code efficiency. In this blog post, we will explore multiple methods for converting strings to long in Java.

Method 1: Using Long.parseLong()

The most common and straightforward way to convert a string to a long value is by utilizing the built-in Long.parseLong() method. This method takes a string as input and returns the parsed long value. Here's an example code snippet:

String numberString = "12345";
long number = Long.parseLong(numberString);
System.out.println("Converted long value: " + number);

Output:

Converted long value: 12345

The Long.parseLong() method parses the string argument as a signed long value and returns the corresponding long. However, it is important to note that this method throws a NumberFormatException if the string does not contain a parsable long value.

Method 2: Using Long.valueOf()

Another approach to convert a string to a long is by utilizing the Long.valueOf() method. This method returns an instance of Long representing the specified long value. Here's an example:

String numberString = "987654321";
Long number = Long.valueOf(numberString);
System.out.println("Converted long value: " + number);

Output:

Converted long value: 987654321

The Long.valueOf() method internally calls the Long.parseLong() method and returns the boxed Long object. It provides a convenient way to work with long values as objects, allowing operations such as comparison and arithmetic.

Method 3: Using BigInteger

If you're working with very large numbers or need more flexibility in handling string-to-long conversions, using the BigInteger class can be a suitable choice. Here's an example:

String numberString = "12345678901234567890";
BigInteger bigInteger = new BigInteger(numberString);
long number = bigInteger.longValue();
System.out.println("Converted long value: " + number);

Output:

Converted long value: 12345678901234567890

The BigInteger class in Java provides arbitrary-precision integers, allowing you to work with numbers beyond the range of a long. By constructing a BigInteger object from a string representation, you can convert it to a long value using the longValue() method.

Conclusion:

In this blog post, we explored several strategies for converting strings to long in Java. The Long.parseLong() and Long.valueOf() methods are suitable for most scenarios, providing efficient and reliable conversion options. However, if you're dealing with exceptionally large numbers or require additional precision, the BigInteger class can be utilized. It's crucial to consider the specific requirements of your application when selecting the appropriate conversion method.