0202面向对象编程基础

# 类声明，类的实例化

<?php

// class 声明一个类
class student{
//类属性
public $name = ‘张三’;
public $age = 20;
//构造方法初始化 $name和$age变量
function __construct($name,$age){

    $this -> name = $name;
    $this -> age = $age;
}
public function mingzi()
{
    return $this->name;
}

}
// new:类实例化
$obj = new student(‘李四’,28);
var_dump($obj);

类的静态成员

<?php
//静态成员
//static 声明静态成员

class user{

public static $name="小花";
public static $sex="女";
// public function __construct($name="张三",$sex="男"){
//     self::$name = $name;
//     self::$sex = $sex;
// }
public static function mingzi(){
    //调用静态成员用类名::静态成员
    return '我叫'.self::$name.'我是'.self::$sex;
}

}
// $yuangong=new user();
// var_dump(user::$name);
echo user::mingzi();

类的扩展

<?php
//类的扩展

class phone{
protected $name = ‘座机’;
protected $gn= ‘打电话’;

public function chi()
{
   return "$this->name , $this->gn";
}

}

$elephant = new phone();
echo $elephant->chi();

class mobile extends phone {

private $yinyue = '音乐';
private $shipin = '视频';
public function zhineng(){
    return "我不仅会 $this->gn ,我还会 $this->yinyue , $this->shipin";
}

}

$gongju = new mobile();
echo $gongju->zhineng();

trait功能

<?php
//通过在类中使用use 关键字，声明要组合的Trait名称，具体的Trait的声明使用Trait关键词，Trait不能实例化
trait dome1{
public $name = ‘老王’;

public function text(){
    return $this->name;
}

}

class dome2{
use dome1;
}

$dome2 = new dome2();
echo $dome2->text();

trait 的冲突与优先级的解决方案

1.优先级解决
2.别名
<?php
trait student{
public function zhangsan(){
return ‘我是张三’;
}
}

trait student2{
public function zhangsan(){
return ‘我也是张三’;
}
}

class student3{

use student,student2{
//优先级
student::zhangsan insteadOf student2;
//别名
student2::zhangsan as T2zhangsan;
}
}

$student3 = new student3();
echo $student3->zhangsan().’<br>‘;
echo $student3->T2zhangsan();

trait与父类的区别与联系

子类>trait>父类
输出子类chi()

没有子类输出trait的chi()

都没有则输出父类的chi();