PHP5 OOP之 static关键字

<?php
//static关键字
class A
{
         public static $aa = 'A::$aa';

         public function static_aa() {
                 return self::$aa;
        }
}

class B extends A
{
         public function static_bb() {
                 return parent::$aa; //调用基类中的公有static属性
        }
        
         //定义静态方法
         public static function b_mystatic()
        {
          echo "我是B的静态方法";
        }
}

print A::$aa. "\n"; //公有可以访问

$a1 = new A();
print $a1->static_aa() . "\n";
//print $a1->aa. "\n";            // 未定义的属性 aa

print B::$aa . "\n"; //继承自A
$b1 = new B();
print $b1->static_bb() . "\n";

B::b_mystatic();
?>