一文搞懂│工厂模式、单例模式、策略模式、适配器模式、观察者模式的原理和使用

<?php/*** 工厂类*/class factory{    public static function create($className) {        return new $className();    }} class A {}class B {} $a = factory::create('A');$b = factory::create('B'); var_dump($a); // object(A)#1 (0) {}var_dump($b); // object(B)#2 (0) {}

<?php/** * Interface shape */interface shape{    public function area();    public function perimeter();} /** * 矩形 * Class rectangle */class rectangle implements shape{    private $width;    private $height;     public function __construct($width, $height) {        $this->width = $width;        $this->height = $height;    }     public function area() {        return $this->width * $this->height;    }     public function perimeter() {        return 2 * ($this->width + $this->height);    }} /** * 圆 * Class circle */class circle implements shape{    private $radius;     public function __construct($radius) {        $this->radius = $radius;    }     public function area() {        return M_PI * pow($this->radius, 2);    }     public function perimeter() {        return 2 * M_PI * $this->radius;    }} /** * 工厂类 * Class factory */class factory{    public static function create() {        switch (func_num_args()) {            case 1:                return new circle(func_get_arg(0));                break;            case 2:                return new rectangle(func_get_arg(0), func_get_arg(1));                break;        }    }} $a = factory::create(4, 5);$b = factory::create(2); echo '矩形的周长为：' . $a->perimeter();echo '矩形的面积为：' . $a->area();echo '圆的周长为：' . $a->perimeter();echo '圆的面积为：' . $a->area();

<?php/** * Class A */class A {} $a = new A();$b = new A();
// 非单例模式中可以看到其中#1，#2分属不同的内存空间var_dump($a); // object(A)#1 (0) {}var_dump($b); // object(A)#2 (0) {}

<?php/** * Class database */class database{    /**     * @var $instance     */    private static $instance;     /**     * 私有的构造方法，禁止外部实例化     * database constructor.     */    private function __construct() {}     /**     * 私有的克隆方法，禁止外部克隆     */    private function __clone() {}     /**     * 获取单例     * @return database     */    public static function getInstance()    {        if(!self::$instance instanceof self) {            self::$instance = new self();        }         return self::$instance;    }} $a = database::getInstance();$b = database::getInstance();
var_dump($a); // object(database)#1 (0) {}var_dump($b); // object(database)#1 (0) {}

<?php/** * Class mysql */class mysql{    /**     * @var \PDO     */    private $pdo;     /**     * @var $instance     */    private static $instance;     /**     * @var array     */    private $_config = [        'host' => '127.0.0.1',        'post' => 3306,        'user' => 'root',        'password' => '',        'charset' => 'utf8',        'dbname' => 'autofelix',        'except' => 'PDO::ERRMODE_EXCEPTION'    ];     /**     * mysql constructor.     */    private function __construct() {}     /**     * 数据库链接     */    public function connect()    {        try {            $dsn = "mysql:host={$this->_config['host']};port={$this->_config['post']};dbname={$this->_config['dbname']};charset={$this->_config['charset']}";            $this->pdo = new PDO($dsn, $this->_config['user'], $this->_config['password']);            $this->pdo->setAttribute(PDO::ATTR_ERRMODE, $this->_config['except']);        } catch (PDOException $e) {            exit('数据库连接失败：' . $e->getMessage());        }    }     /**     * @param $sql     * @return array     */    public function getAll($sql)    {        $this->sql = $sql;        $pdostatement = $this->pdo->query($sql);        return $pdostatement->fetchAll(PDO::FETCH_ASSOC);    }     /**     * @return mysql     */    public static function getInstance()    {        if(!self::$instance instanceof self) {            self::$instance = new self();        }        return self::$instance;    }     private function __clone() {}} $mysql = mysql::getInstance();$mysql->connect(); $sql = 'select * from autofelix_users where 1';$result = $mysql->getAll($sql);echo json_encode($result);

<?php/** * Class A */class A {    public function name()    {        echo "我是A类";    }} /** * Class B */class B {    public function name()    {        echo "我是B类";    }} /** * Class strategy */class strategy{    /**     * @var $obj     */    private $obj;     /**     * @return mixed     */    public function getName()    {        return $this->obj->name();    }     /**     * @param $class     */    public function setClass($class)    {        $this->obj = $class;    }} $strategy = new strategy();// 分门别类// $strategy->setClass(new A());$strategy->setClass(new B());// 同一个入口$strategy->getName(); // 我是B类

<?php/** * 定义接口 * Interface userStrategy */interface userStrategy{    public function hotel();    public function dinner();} /** * 尊贵的客人享有的待遇 * Class rich */class rich implements userStrategy{    public function hotel()    {        return "你是高贵的客人，为你推荐了高级住宿";    }     public function dinner()    {        return "你是高贵的客人，为你推荐了烛光晚餐";    }} /** * 普通的客人享有的待遇 * Class poor */class poor implements userStrategy{    public function hotel()    {        return "你是普通的客人，为你推荐了大众住宿";    }     public function dinner()    {        return "你是普通的客人，为你推荐了自助餐";    }} /** * Class user */class user{    private $_userClass;     public function getHotel() {        return $this->_userClass->hotel();    }     public function getDinner() {        return $this->_userClass->dinner();    }     public function setUserClass(userStrategy $userStrategy) {        $this->_userClass = $userStrategy;    }} /** * 这时候有个autofelix用户过来网站预定房间 * Class autofelix */class autofelix extends user {} $people = new autofelix(); //设置群体$people->setUserClass(new poor()); //获取该群体的住宿和晚餐$hotel = $people->getHotel();$dinner = $people->getDinner(); echo json_encode([    'hotel' => $hotel,    'dinner' => $dinner]);
// 结果如下{    hotel: "你是普通的客人，为你推荐了大众住宿",    dinner: "你是普通的客人，为你推荐了自助餐"}

<?php class A{    private $str;     public function __construct($str)    {        $this->str = $str;    }     public function getStr()    {        return $this->str;    }     // 错误示范，直接复制 getStr 中的代码改个方法名，臃肿    public function getString()    {        return $this->str;    }} //适配器模式前$a = new A('i am autofelix');$result = $a->getStr();var_dump($result);

<?php// 项目原本代码class A{    private $str;     public function __construct($str)    {        $this->str = $str;    }     public function getStr()    {        return $this->str;    }}
// 定义统一接口interface AInterface {    function getString();} class B implements AInterface{    /**     * @var A     */    private $_A;     public function __construct($class)    {        $this->_A = $class;    }     public function getString()    {        return $this->_A->getStr();    }} // 适配器模式前$a = new A('i am autofelix');$result = $a->getStr();var_dump($result);
// 适配器模式后$b = new B($a);$result = $b->getString();var_dump($result);

// 系统自带的观察者接口// 默认需要实现 onListen 和 getObserverName 这两个方法// 如果是自定义观察者接口名，一定要实现onListen同功能的方法// onListen 注册监听行为interface InterfaceObserver{    public function onListen($sender, $args);    public function getObserverName();}
// 定义可被观察者的接口// 其实就是用来监听事件的发生// addObserver 方法我们是用来依赖注入一些用户购票之后系统的行为操作// removeObserver 方法，是用来移除某个后续操作的，我们暂时不去实现interface InterfaceObservable{    public function addObserver($observer);    public function removeObserver($observer_name);}

<?php/** * Interface InterfaceObserver * 观察者接口 */interface InterfaceObserver{    public function onListen($sender, $args);    public function getObserverName();} /** * Interface InterfaceObservable * 被观察对象接口 */interface InterfaceObservable{    public function addObserver($observer);    public function removeObserver($observer_name);} class Ticket implements InterfaceObservable{    /**     * @var array     */    private $_observers = [];     /**     * @param $observer     */    public function addObserver($observer)    {        if ($observer instanceof InterfaceObserver) {            $this->_observers[] = $observer;        }    }     /**     * @param $observer_name     */    public function removeObserver($observer_name) {}     /**     * 用户购票行为     */    public function buy()    {        //用户购票逻辑,这里不详细说明,仅仅以参数代之        $result = [            'code' => 200,            'msg' => '用户购票成功',            'sign' => 'ea5070bec29826cc0f8e0b7b6861fd75'        ];         //购票成功，开始后期处理        if($result['code'] == 200) {            foreach ($this->_observers as $observer) {                $observer->onListen($this, $result['sign']);            }        }    }}  /** * 记录用户购票日志 * Class TicketRecord */class ticketRecord implements InterfaceObserver{    public function onListen($sender, $args)    {        echo "记录用户购票成功,编号为:{$args}<br/>";    }     public function getObserverName() {}} /** * 给用户发送观影短信 * Class sendMsg */class sendMsg implements InterfaceObserver{    public function onListen($sender, $args)    {        echo "您的电影票购买成功,请凭编号:{$args}观影<br/>";    }     public function getObserverName() {}} $ticket = new Ticket();$ticket->addObserver(new ticketRecord());$ticket->addObserver(new sendMsg());$ticket->buy();