php 魔术方法

<?php
    class test {
        public function  __construct() {
            echo '__construct';
        }

        public function  __destruct() {
            echo '__destruct';
        }

        public function  __get($key) {
            echo '__get';
        }

        public function  __set($key,$value) {
            echo '__set';
        }

        public function  __call($key, $args) {
            echo '__call';
        }

        public function  __toString() {
            echo '__toString';
        }

        public function  __clone() {
            echo '__clone';
        }
    }
    $test = new test();
?>