php class中self,parent,this的区别以及实例介绍_PHP教程

class test{
public $public;
private $private;
protected $protected;
static $instance;
static $good = 'tankzhang <br>';
public $tank = 'zhangying <br>';

public function __construct(){
$this->public = 'public <br>';
$this->private = 'private <br>';
$this->protected = 'protected <br>';

}
public function tank(){ //私有方法不能继承，换成public,protected
if (!isset(self::$instance[get_class()]))
{
$c = get_class();
self::$instance = new $c;
}
return self::$instance;
}

public function pub_function() {
echo "you request public function<br>";
echo $this->public;
}
protected function pro_function(){
echo "you request protected function<br>";
echo $this->protected;
}
private function pri_function(){
echo "you request private function<br>";
echo $this->private;
}
static function sta_function(){
echo "you request static function<br>";
}
}

class test1 extends test{

static $love = "tank <br>";
private $aaaaaaa = "ying <br>";

public function __construct(){
parent::tank();
parent::__construct();
}
public function tank(){
echo $this->public;
echo $this->protected;
echo $this->aaaaaaa;
$this->pro_function();
}

public function test1_function(){
echo self::$love;
echo self::$good;
echo parent::$good;
echo parent::$tank; //Fatal error: Access to undeclared static property: test::$tank
echo self::$tank; //Fatal error: Access to undeclared static property: test::$tank
}
static function extends_function(){
parent::sta_function();
self::pro_function();
echo "you request extends_private function<br>";
}
}

error_reporting(E_ALL);
$test = new test1();
$test->tank(); //子类和父类有相同名字的属性和方法，实例化子类时，会调用子类中的方法。
test1::test1_function();
test1::extends_function(); //执行一部分后，报Fatal error: Using $this when not in object context in D:\xampp\htdocs\mytest\www4.php on line 32
?>