php custom exception handling

First, I'd recommend to take a look at corresponding PHP manual page, it's great place to start. Also, you can take a look at Extending Exceptions page - there are some more info about standard exception class, and example of custom exception implementation.

If the question is, how to do some specific action if exception of particular type was thrown, then you just have to specify exception type in catch statement:

    try {
        //do some actions, which may throw exception
    } catch (MyException $e) {
        // Specific exception - do something with it
        // (access specific fields, if necessary)
    } catch (Exception $e) {
        // General exception - log exception details
        // and show user some general error message
    }

Try this as the first thing on your php page(s).

It captures php errors and exceptions.

function php_error($input, $msg = '', $file = '', $line = '', $context = '') {
    if (error_reporting() == 0) return;

    if (is_object($input)) {
        echo "<strong>PHP EXCEPTION: </strong>";
        h_print($input);
        $title  = 'PHP Exception';
        $error  = 'Exception';
        $code   = null;
    } else {
        if ($input == E_STRICT) return;
        if ($input != E_ERROR) return;
        $title  = 'PHP Error';
        $error  = $msg.' in <strong>'.$file.'</strong> on <strong>line '.$line.'</strong>.';
        $code   = null;
    }

    debug($title, $error, $code);

}

set_error_handler('php_error');
set_exception_handler('php_error');

Official docs is a good place to start - http://php.net/manual/en/language.exceptions.php.

If it is just a message that you want to capture you would do it at follows;

try{
    throw new Exception("This is your error message");
}catch(Exception $e){
    print $e->getMessage();
}

If you want to capture specific errors you would use:

try{
    throw new SQLException("SQL error message");
}catch(SQLException $e){
    print "SQL Error: ".$e->getMessage();
}catch(Exception $e){
    print "Error: ".$e->getMessage();
}

For the record - you'd need to define SQLException. This can be done as simply as:

class SQLException extends Exception{

}

---

For a title and message you would extend the Exception class:

class CustomException extends Exception{

    protected $title;

    public function __construct($title, $message, $code = 0, Exception $previous = null) {

        $this->title = $title;

        parent::__construct($message, $code, $previous);

    }

    public function getTitle(){
        return $this->title;
    }

}

You could invoke this using :

try{
    throw new CustomException("My Title", "My error message");
}catch(CustomException $e){
    print $e->getTitle()."<br />".$e->getMessage();
}