mysql面向对象抽象类和接口-白红宇

mysql面向对象抽象类和接口

阅读量：5020 次

发布时间：2019-06-12

本文共 3237 字，大约阅读时间需要 10 分钟。

抽象类：含有抽象方法的类【abstract 抽象关键词】

1 abstract class Usb 2 { 3     public function load(){ 4         echo "Usb is loading
"; 5     } 6  7     public function start(){ 8         echo "Usb is starting
"; 9     }10 11     # 抽象方法12     abstract public function unload();13 }14 15 # 子类16 class Upan extends Usb17 {18     # 调用需先实现unload抽象方法19     public function unload(){20         echo "Usb is unloading
";21     }22 23     public function jitui(){24         echo "我喜欢鸡腿
";25     }26 }27 28 $obj = new Upan();29 $obj->load();

接口：只含有抽象方法的类【interface、abstract 抽象关键词】

1 interface Usb 2 { 3     public function load(); 4  5     public function start(); 6  7     public function unload(); 8 } 9 10 # 子类11 class Upan implements Usb12 {13     public function load(){14         echo "Usb is loading
";15     }16 17     public function start(){18         echo "Usb is starting
";19     }20 21     public function unload(){22         echo "Usb is unloading
";23     }24 }25 26 # 调用前需全部实现Usb类中的抽象方法27 $obj = new Upan();28 $obj->load();

一个子类实现多个接口

1 interface Usb 2 { 3     public function load(); 4  5     public function start(); 6  7     public function unload(); 8 } 9 10 interface Usb211 {12     public function run();13 }14 15 # 子类16 class Upan implements Usb,Usb217 {18     public function load(){19         echo "Usb is loading
";20     }21 22     public function start(){23         echo "Usb is starting
";24     }25 26     public function unload(){27         echo "Usb is unloading
";28     }29 30     public function run(){31         echo "Usb2 is runing
";32     }33 }34 　　　　35 $obj = new Upan();36 $obj->load();

接口扩展，只能继承不能实现，一般不常用

1 interface Usb 2 { 3     public function load(); 4  5     public function start(); 6  7     public function unload(); 8 } 9 10 interface Usb2 extends Usb11 {12     public function run();13 }14 15 # 子类16 class Upan implements Usb217 {18     public function load(){19         echo "Usb is loading
";20     }21 22     public function start(){23         echo "Usb is starting
";24     }25 26     public function unload(){27         echo "Usb is unloading
";28     }29 30     public function run(){31         echo "Usb2 is runing
";32     }33 }34 35 $obj = new Upan();36 $obj->load();

多态小实例

1 interface Usb 2 { 3     public function load(); 4  5     public function start(); 6  7     public function unload(); 8 } 9 10 # 子类11 class Upan implements Usb12 {13     public function load(){14         echo "Usb is loading
";15     }16 17     public function start(){18         echo "Usb is starting
";19     }20 21     public function unload(){22         echo "Usb is unloading
";23     }24 25     public function run(){26         echo "Usb2 is runing
";27     }28 }29 30 # 非法类31 class Udisk32 {33     public function load(){34         echo "Usb is loading
";35     }36 37     public function start(){38         echo "Usb is starting
";39     }40 41     public function unload(){42         echo "Usb is unloading
";43     }44 }45 46 # 只有实现了Usb接口中所有方法才能正常调用47 function useUsb(Usb $o){48     $o->load();49     $o->start();50     $o->unload();51     echo "
       
";52 }53 54 $obj = new Upan();55 $obj2 = new Udisk();56 useUsb($obj);57 useUsb($obj2); #失败