PHP中静态方法和非静态方法的相互调用

在PHP的非静态方法中可以调用静态方法

class test{

    public static function strPrint(){
        echo 'this is strPrint static function<br>';
    }

    public function staticFuncInvoke(){
        self::strPrint();
    }
}

$test = new test();

$test->staticFuncInvoke();

上面的代码会输出: this is strPrint static function.

而下面的代码会直接挂掉，php直接给出fatal error：

　　Fatal error: Using $this when not in object context in E:\htdocs\test\content.php on line 6

class test{

    public static function strPrint(){
        $this->staticFuncInvoke();
    }

    public function staticFuncInvoke(){
        echo 'this is a nonstatic function named staticFuncInvoke';
    }
}

test::strPrint();