Home > Java > javaTutorial > body text

Solution to NumberFormatException exception in Java

王林
Release: 2023-06-25 18:52:18
Original
2280 people have browsed it

An exception that often occurs in Java is NumberFormatException. This is because when using a string to parse a number, if the string contains non-numeric characters, this exception will be triggered. This article will introduce the solution to the NumberFormatException exception.

  1. Form verification

In a form for inputting numbers, in order to prevent users from making mistakes, verification is generally required. For example, you can use regular expressions to check whether the input string is a number. If it is not a number, an exception is thrown. The following is an example:

String input = "abc123";
if (!input.matches("\d+")) {
    throw new NumberFormatException("输入的不是数字!");
}
int num = Integer.parseInt(input);
Copy after login
  1. Exception catching

In the program, if you clearly know that the input string may contain non-numeric characters, you can solve the NumberFormatException by exception catching abnormal. The following is an example:

String input = "abc123";
try {
    int num = Integer.parseInt(input);
} catch (NumberFormatException e) {
    System.out.println("输入的不是数字!");
    e.printStackTrace();
}
Copy after login
  1. Default value for converting string to number

In some cases, in order to avoid program interruption due to NumberFormatException exception, you can set Default value for converting string to number. For example, if the input is a null character, the default number is 0. The following is an example:

String input = "";
int num;
try {
    num = Integer.parseInt(input);
} catch (NumberFormatException e) {
    num = 0;
}
System.out.println(num); // 输出0
Copy after login
  1. Check whether the string is empty

When using a string to convert a number, you need to pay attention to whether the input string is empty. If the input string is empty, conversion cannot occur. Therefore, it is recommended to first determine whether the string is empty before performing the conversion operation. The following is an example:

String input = "";
if (input != null && input.length() > 0) {
    int num = Integer.parseInt(input);
} else {
    System.out.println("输入的字符串为空,无法转为数字!");
}
Copy after login

In short, when converting a string to a number, pay attention to whether the entered characters are numbers and whether they are empty. If necessary, you can use exception catching to handle NumberFormatException exceptions. Through these methods, NumberFormatException exceptions can be solved more efficiently.

The above is the detailed content of Solution to NumberFormatException exception in Java. For more information, please follow other related articles on the PHP Chinese website!

source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template
About us Disclaimer Sitemap
php.cn:Public welfare online PHP training,Help PHP learners grow quickly!