<?php/**PHP的多态某种对象实例的不同表现形态。父类引用指向子类对象，然后调用父类方法，去执行子类覆盖父类的那个方法。*/abstractclassFruit{publicabstractfunctioncut();}classBananaextendsFruit{publicfunctioncut(){echo'好恶心';}}classAppleextendsFruit{publicfunctioncut(){echo'切成一块一块的';}}classKnife{publicstaticfunctiontool(Fruit$ft){$ft->cut();}}Knife::tool(newBanana());echo'<br>';Knife::tool(newApple());?>