PHP의 인터페이스와 추상 클래스의 차이점과 인터페이스 인스턴스 코드를 정의하고 상속하는 방법에 대한 자세한 설명

<?php
//简单定义实现接口
interface UserInterface{  //定义user接口
    function getname();
}
interface TeacherInterface{    //定义teacher接口
    function getLengthofService();
}
class User implements UserInterface{ //实现user接口
    private $name="nostop";
    public function getName(){
        return $this->name;
    }
}
class Teacher implements TeacherInterface{ //实现teacher接口
    private $age=23;
    public function getLengthofService(){
        return $this->age;
    }
}
$user=new User();
echo $user->getName().&#39;<br />&#39;;//nostop
$teacher=new Teacher();
echo $teacher->getLengthofService().&#39;<br />&#39;;//23
//继承类实现接口
class GraduResultudent extends User implements TeacherInterface{ //继承User类 实现接口
    private $teacher;
    public function construct(){     //定义构造函数
        $this->teacher=new Teacher();  //实例化Teacher对象
    }
    public function getLengthOfService(){ //实现TeacherInterface接口的方法
        return $this->teacher->getLengthOfService();
    }
}
class Result{
    public static function getUserName(UserInterface $_user){ //注意：这里面的类型变成接口类型
        echo "Name is ".$_user->getName().&#39;<br />&#39;;
    }
    public static function getLengthOfService(TeacherInterface $_teacher){ //注意：这里面的类型变成接口类型
        echo "age is ".$_teacher->getLengthOfService();
    }
}
$object=new GraduResultudent();
Result::getUserName($object); //Name is nostop
Result::getLengthOfService($object); //age is 23
echo "<br />";
//接口实现用户的折扣
interface People{    //定义接口
    function getUserType();
    function getCount();
}
class VipUser implements People{ //实现接口
    //用户折卡系数
    private $discount=0.8;
    function getUserType(){
        return "VIP用户";
    }
    function getCount(){
        return    $this->discount;       
    }
}
$vip=new VipUser();    //实现化对象
echo $vip->getUserType().&#39;商品价格：&#39;.$vip->getCount()*100;  //VIP用户商品价格：80
class Goods{
    var $price=100;
    var $member;
    function run(People $member){ //注意：这里面的参数类型是接口类型
        $this->member=$member;
        $discount=$this->member->getCount();
        $usertype=$this->member->getUserType();
        echo $usertype."商品价格：".$this->price*$discount;
    }
}
$display=new Goods();
$display->run(new VipUser);//VIP用户商品价格：80
?>