A detailed analysis of error handling and exception handling methods based on PHP7

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PHP7 Error Handling

PHP 7 Changes the way most errors are reported. Unlike the Legacy (PHP 5) Error reporting mechanism, most errors are now thrown as error exceptions.

This Error exception can be captured as a Exception exception by the first matching try/catch block. If there is no matching catch block, the exception handler is called (prior to Set_exception_handler () registration) for processing. If the exception handler has not been registered, it is handled in the traditional way: it is reported as a fatal error (Fatal error).

The Error class does not inherit from the Exception class, so you cannot use catch (Exception e) ... To capture the error. You can catch the Error by catching (Errore) {...}, or by registering the exception handler (Set_exception_handler ()).

Error hierarchy

Throwable Error  arithmeticerror   pisionbyzeroerror  assertionerror  parseerror  TypeError Exception ...  

try{//Code that could throw an Exception or Error.} catch (Throwable $t) {//Executed only in PHP 7, would not match in PHP 5}catch (Exception $e) {//Executed only in PHP 5, Won't is reached in PHP 7}updown9lubaev dot ka at gmail dot com¶11 months agophp 7.1try {//Code ' may throw an Ex Ception or Arithmeticerror.} catch (Arithmeticerror | Exception $e) {//pass}

Extended (Extend) PHP built-in exception handling class

Users can use custom exception handling classes to extend PHP's built-in exception handling classes. The following code shows which properties and methods are accessible and inherited in the subclass of the built-in exception-handling class.

Example #1 built-in exception handling classes

<?phpclass exception{protected $message = ' Unknown Exception ';//exception information private $string;      __tostring Cache protected $code = 0;       User-defined exception code protected $file;       The file name of the exception that occurred protected $line;       The code line number where the exception occurred private $trace;      BackTrace private $previous; Previous exception if nested exception public function __construct ($message = null, $code = 0, exception $previous = Nu ll);   Final Private Function __clone (); Inhibits cloning of exceptions.  Final public Function getMessage ();   Returns the exception information final public function getcode ();   Returns the exception code final public function GetFile ();   Returns the file name of the exception that occurred final public function getLine ();   Returns the line number of the code where the exception occurred. Final public function gettrace ();  BackTrace () array final public function getprevious (); Previous exception final public function gettraceasstring ();    Gettrace () information that has been rasterized into a string//overrideable Public Function __tostring (); Output string}?> If you use a custom class to extend the built-in exception-handling class, and you want to redefine the constructor, it is recommended that you call Parent::__construct () at the same time to check that all variables have been assigned values. When an objectTo output a string, you can overload __tostring () and customize the style of the output. The Note:exception object cannot be copied. Attempting to copy a Exception object causes an E_error level of error.

<?php/** * Customizing an exception handling class */class MyException extends exception{//redefine the constructor to make the message a property that must be specified public function __construct ( $message, $code = 0, Exception $previous = null) {//Custom code//Make sure all variables are correctly assigned Parent::__construct ($message, $code, $prev IOUs); }//Custom string output style public function __tostring () {return __class__. ": [{$this->code}]: {$this->message}\n"; } public Function Customfunction () {echo ' A Custom function for this type of exception\n ';}} /** * Create a class to test the exception handling mechanism */class testexception{public $var; const THROW_NONE = 0; Const THROW_CUSTOM = 1; Const THROW_DEFAU LT = 2; function __construct ($avalue = self::throw_none) {switch ($avalue) {case Self::throw_custom://Throw custom exception throw n    EW MyException (' 1 is an invalid parameter ', 5);   Break    Case Self::throw_default://throws the default exception throw new Exception (' 2 is not allowed as a parameter ', 6);   Break    Default://Without exception, create an object $this->var = $avalue;  Break } }}

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