javastring转long类型(JAVAstring类型)

Introduction

Java is a programming language that is widely used in developing applications for different platforms including web, desktop, and mobile devices. In Java, there are different data types including int, double, float, and long, among others. In this article, we will focus on how to convert a string to a long data type in Java.

Converting String to Long using parseLong method

Java has a built-in method called parseLong that is used to convert a string to a long data type. The method parses the string argument as a signed decimal long and returns a long value. The syntax for using parseLong method is as follows:

long variableName = Long.parseLong(string);

For example, in the code snippet below, we have a string called “numberString” that contains a numerical value, and we want to convert it to a long data type:

String numberString = "12345678910";
long numberLong = Long.parseLong(numberString);

In the above code, we used the parseLong method to convert the string “numberString” to a long data type.

Handling Exceptions in parseLong method

It is important to note that using parseLong method can result in a NumberFormatException if the string is not a valid long value. For example, if the string contains alphabetic characters, it cannot be converted to a long data type. To handle such an exception, we can use a try-catch block. The syntax for the try-catch block is as follows:

try {
    long variableName = Long.parseLong(string);
} catch (NumberFormatException e) {
    System.err.println("Invalid long value: " + e.getMessage());
}

In the code snippet above, if the string cannot be parsed into a long value, a NumberFormatException is thrown and caught in the catch block. The error message is then displayed on the console.

Conclusion

Converting a string to a long data type in Java is a straightforward process that can be achieved using the parseLong method. However, it is important to handle exceptions that may arise during the conversion process. By using the try-catch block, we can ensure that our program handles any errors that may occur, resulting in a more robust and reliable application.