Error handling mechanism in PHP7: How to better manage and catch errors?

Error handling mechanism in PHP7: How to better manage and catch errors?

Introduction:
Error handling is a very important part of programming, it can help us better debug and manage code. PHP7 has improved the error handling mechanism and provides more powerful functions and flexibility. This article will introduce how to better manage and capture errors in PHP7, and provide specific code examples.

1. Error reporting level and settings
In PHP7, we can set the level of error reporting by modifying the php.ini file. You can decide which errors need to be reported and where to send the error reports by setting the error_reporting parameter.

Sample code:

// 设置错误报告级别，显示所有错误
error_reporting(E_ALL);

// 将错误报告发送到日志文件
ini_set('log_errors', 1);
ini_set('error_log', '/path/to/error.log');

By setting the error reporting level to E_ALL, we can catch all types of errors, which helps to check potential problems in the code.

2. Custom error handling function
PHP7 introduces a new error handling function: set_error_handler. We can use this function to customize the behavior of error handling instead of using the default error handling mechanism.

Sample code:

// 定义自定义错误处理函数
function customErrorHandler($errno, $errstr, $errfile, $errline)
{
    // 错误处理逻辑
    echo "Error [$errno]: $errstr in $errfile on line $errline";
}

// 设置自定义错误处理函数
set_error_handler("customErrorHandler");

In the above code, we define a custom error handling function named "customErrorHandler". Then set it as the default error handling function by calling the set_error_handler function.

3. Exception handling mechanism
In addition to error handling functions, PHP7 also introduces an exception handling mechanism. An exception is an object that is thrown when an error occurs during code execution. We can use try-catch block to catch and handle exceptions.

Sample code:

// 定义自定义异常处理类
class CustomException extends Exception
{
    public function errorMessage()
    {
        // 异常处理逻辑
        return 'Error ['.$this->getCode().']: '.$this->getMessage().' in '.$this->getFile().' on line '.$this->getLine();
    }
}

try {
    // 抛出异常
    throw new CustomException('This is a custom exception.');
} catch (CustomException $e) {
    // 捕获异常
    echo $e->errorMessage();
}

In the above code, we define a custom exception handling class named "CustomException", which is a subclass of the Exception class. Then, a custom exception object is thrown in the try block, and the exception is caught and handled in the catch block.

4. The difference between error handling and exception handling
Error handling and exception handling are both used to handle errors that occur during code execution. The main difference between them is that error handling actively handles errors in the code, while exception handling throws exceptions in the code and then catches them through try-catch blocks.

Error handling is more suitable for some foreseeable errors, such as file reading failure, undefined variables, etc.; while exception handling is suitable for some unforeseen errors or exceptions in business logic.

The choice of error handling and exception handling should be determined based on specific needs and situations.

Conclusion:
PHP7 provides a more powerful and flexible error handling mechanism, including error reporting level settings, custom error handling functions, exception handling mechanisms, etc. Proper use of these functions can better manage and capture errors, and improve the robustness and maintainability of the code.

Reference materials:

• PHP documentation: https://www.php.net/manual/en/function.error-reporting.php
• PHP documentation : https://www.php.net/manual/en/function.set-error-handler.php
• PHP Documentation: https://www.php.net/manual/en/language.exceptions .php
• PHP documentation: https://www.php.net/manual/en/language.exceptions.extending.php

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