PHP Exception Handling Guide

In PHP, exception handling is a mechanism for handling errors that occur during runtime by throwing and catching exceptions. Exceptions are objects used to represent error states, and they inherit from the Exception class.

The main advantage of exception handling is that it allows the error handling logic to be separated from the normal business logic, thereby increasing code maintainability and stability.

The basic usage of the abnormality is as follows:

1. Throw exception.

throw new Exception('Error message');

1. Catch an exception.

try {
    // 业务逻辑代码
    if ($error_condition) {
        throw new Exception('Error message');
    }
} catch (Exception $e) {
    // 异常处理逻辑
    echo 'Caught exception: ' . $e->getMessage();
}

1. Custom exception class:

class CustomException extends Exception {
    public function customFunction() {
        echo 'Custom exception function';
    }
}

try {
    if ($error_condition) {
        throw new CustomException('Custom error message');
    }
} catch (CustomException $e) {
    echo 'Caught custom exception: ' . $e->getMessage();
    $e->customFunction();
}

In practical applications, exception handling is often combined with functions such as logging and displaying error pages to provide a better user experience and improve error localization capabilities.