## final 關鍵字 如果父類中的方法被聲明為 `final`，則子類無法覆蓋該方法。如果一個類被聲明為 `final`，則不能被繼承。 父類方法被聲明為 `final`： ``` <?php class BaseClass { public function test() { echo "BaseClass::test() called." . PHP_EOL; } final public function moreTesting() { echo "BaseClass::moreTesting() called." . PHP_EOL; } } class ChildClass extends BaseClass { public function moreTesting() { echo "ChildClass::moreTesting() called." . PHP_EOL; } } // Results in Fatal error: Cannot override final method BaseClass::moreTesting() ?> ``` 父類被聲明為 `final`： ``` <?php final class BaseClass { public function test() { echo "BaseClass::test() called." . PHP_EOL; } public public function moreTesting() { echo "BaseClass::moreTesting() called." . PHP_EOL; } } class ChildClass extends BaseClass { } // Fatal error: Class ChildClass may not inherit from final class (BaseClass) ?> ```