我为什么要在php中使用异常处理？

class Application
{
    public function run()
    {
        try {
            // Start her up!!
        } catch (Exception $e) {
            // If Ajax request,send back status and message
            if ($this->getRequest()->isAjax()) {
                return Application_Json::encode(array(
                    'status' => 'error','msg'    => $e->getMessage());
            }

            // ...otherwise,just throw error
            throw $e;
        }
    }
}

然后,可以通过自定义错误处理程序处理抛出的异常.

由于PHP是一种松散类型的语言,因此您可能需要确保只将字符串作为参数传递给类方法.例如…

class StringsOnly
{
    public function onlyPassStringToThisMethod($string)
    {
        if (!is_string($string)) {
            throw new InvalidArgumentException('$string is definitely not a string');
        }

        // Cool string manipulation...

        return $this;
    }
}

…或者如果您需要以不同方式处理不同类型的异常.

class DifferentExceptionsForDifferentFolks
{
    public function catchMeIfYouCan()
    {
        try {
            $this->flyForFree();
        } catch (CantFlyForFreeException $e) {
            $this->alertAuthorities();
            return 'Sorry,you can't fly for free dude. It just don't work that way!';
        } catch (DbException $e) {
            // Get DB debug info
            $this->logDbDebugInfo();
            return 'Could not access database. What did you mess up this time?';
        } catch (Exception $e) {
            $this->logMiscException($e);
            return 'I catch all exceptions for which you did not account!';
        }
    }
}

如果在Zend Framework中使用事务：

class CreditCardController extends Zend_Controller_Action
{
    public function buyforgirlfriendAction()
    {
        try {
            $this->getDb()->beginTransaction();

            $this->insertGift($giftName,$giftPrice,$giftWowFactor);

            $this->getDb()->commit();
        } catch (Exception $e) {
            // Error encountered,rollback changes
            $this->getDb()->rollBack();

            // Re-throw exception,allow ErrorController forward
            throw $e;
        }
    }
}