How to create a custom exception handler in PHP?

How to create a custom exception handler in PHP? (1) Create a custom exception class, inherited from the Exception class; (2) Use the set_exception_handler() function to register an exception handler to catch exceptions; (3) In the handler, handle exceptions according to the exception type, such as recording exceptions , provide a friendly error message, or take recovery action.

How to create a custom exception handler in PHP

Exception handling in PHP allows you to handle it gracefully at runtime Errors and exceptions. Custom exception handlers provide a way to customize error handling, thereby enhancing application robustness and user experience.

Create a custom exception class

First, you need to create a custom exception class. This will subclass PHP's built-in Exception class:

class MyCustomException extends Exception
{
    // ...
}

Registering an exception handler

Once you create your custom exception class, you You need to use the set_exception_handler() function to register an exception handler. This handler will be executed every time any type of exception is thrown:

set_exception_handler(function (Throwable $exception) {
    // 处理异常
});

Handling exceptions in handlers

In handlers you can access exceptions Object and take appropriate action:

• Log exception information: Write exception message to log file or database.
• Provide friendly error messages: Show the user a short, easy-to-understand description of the exception.
• Take recovery action: Attempt to restore the application's state or retry the operation.
• Rethrow exceptions: If an exception cannot be handled, you can rethrow it to let other code handle it.

Practical Case

Suppose you have an application that needs to handle file operation errors. You can create a custom exception class FileOperationException to handle these errors:

class FileOperationException extends Exception
{
    public function __construct($message, $code = 0, Throwable $previous = null)
    {
        parent::__construct($message, $code, $previous);
    }
}

and register an exception handler with the following code:

set_exception_handler(function (Throwable $exception) {
    if ($exception instanceof FileOperationException) {
        // 处理文件操作错误
    } else {
        // 处理其他类型的异常
    }
});

Now, when thrownFileOperationException When a custom handler is triggered, you can take custom actions for file operation errors.

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