Exception handling in PHP
Exception handling
An exception is an event that occurs at time of execution of program / script that interrupt the execution of the program. PHP 5 introduce the mechanism of exception that handle the error condition in case of object.
PHP 5 has the exception model similar to the other object oriented programming languages and provide three keywords to handle the exception
- Try
- Catch
- Throw
Try block
PHP uses a keyword try to preface a block of code that is likely to cause an error condition.
Syntax
try { Code here; }
If any exception occur in try block an exception handler associated with it handlers that exception. To associate an exception with try block you must put catch block after try blog.
Catch Block
It is used to catch the exception you can write multiple catch block for single try block. Each catch block contains handler of try block. Catch block code is executed when exception occur in try block.
Syntax
try { Code here; } Catch(ExceptionType name) { Code here; }
Note:
If the exception occurs, PHP code after the statement will not be executed so that used try-catch block.
Throw
Throw statement is used to throw the new exception that require the single argument.
Syntax
throw new Exception; you can also pass the custom error message to the exception object throw new Exception( “problem occur” );
Example with exception
function Fun($number) { return $number; } try { $a = Fun(200); if($a > 80); throw new Exception("Value must be less than 80"); if($a < 100); throw new Exception("Value must be greator than 100"); } catch(Exception $e) { echo 'Message: ' .$e->getMessage(); }
Output
Multiple exception
<?php function Fun($number) { return $number; } try { $a = Fun(200); if($a > 80); throw new Exception("Value must be less than 80"); if($a < 100); throw new Exception("Value must be greater than 100"); } catch(Exception $e) { echo 'Message: ' .$e->getMessage(); } ?>
Output
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