练习案例：
/demo1.php
<?php//命名空间namespace w1205;//单列模式原理//创建类class Demo1{//构造方法 私有化private function __construct(){}//创建静态属性public static $inst;//实例化public static function get(){//判断返回当前类实例 没有就实例化 已经存在就返回他if (is_null(self::$inst)){self::$inst = new self();// echo '111';}return self::$inst;}//当前类禁用魔术克隆方法private function __clone(){}}//实例化Demo1$obj1 = Demo1::get();$obj2 = Demo1::get();var_dump($obj1,$obj2);echo '<br>';var_dump($obj1 === $obj2);echo '<hr>';/**********************************///单列模式应用场景//创建类class Db{//构造方法 私有化private function __construct(...$data){//配置数据库基本资料$dsn = $data[0];$username = $data[1];$password = $data[2];self::$pdo = new \PDO($dsn,$username,$password);}//创建静态属性public static $pdo;//实例化public static function get(...$data){//判断返回当前类实例 没有就实例化 已经存在就返回他if (is_null(self::$pdo)){new self(...$data);}return self::$pdo;}//当前类禁用魔术克隆方法private function __clone(){}}//实例化Db$data = ['mysql:host=127.0.0.1;dbname=phpcn','root','root66'];$pdo = Db::get(...$data);print_r($pdo->query('SELECT * FROM `user`')->fetchAll());
/demo2.php
<?php//命名空间namespace w1205;//工厂模式 批量创建类的实例或对象//创建类class test1{public function __construct($arg1){echo '成功创建参数：' . $arg1;}}class test2{public function __construct($arg1,$arg2){echo '成功创建参数：' . $arg1 . '---' . $arg2 ;}}class test3{public function __construct($arg1,$arg2,$arg3){echo '成功创建参数：' . $arg1 . '---' . $arg2 . '---' . $arg3;}}//工厂类class Factory{public static function create($name,...$data){return new $name(...$data);}}//使用工厂类实例化Factory::create(test1::class,111);Factory::create(test2::class,111,222);Factory::create(test3::class,111,222,333);
/demo3.php
<?php//命名空间namespace w1205;//依赖注入 用来解决对象调用之间的耦合//工作类class P{//需要依赖外部对象private $car;//将注入点放到构造方法中public function __construct(Car $car){$this->car = $car;}//从外部对象执行操作public function work(){return $this->car->drive();}}//需要依赖对的外部类class Car{public function drive(){return '开车！！！';}}//实例化类$car = new Car();$p = new P($car);echo $p->work();
/M.PHP
<?php//命名空间namespace w1205;//设置数据class M{public function get(){return '中国';}}
/P.php
<?phpnamespace w1205;//数据class P{public function get(M $m){return '我们是' . $m->get() .'人';}}
<?phpnamespace w1205;//容器类class C{//实例当前类容器protected $inst = [];//将类实例化的过程绑定到容器public function bind($alias,\Closure $P){$this->inst[$alias] = $P;}//取出保存在容器中的实例化过程闭包 执行public function M($alias){return $this->inst[$alias]();}}
/demo1.php
<?phpnamespace w1205;//调用文件//不调用C容器类require 'P.php';require 'M.php';//创建类class Client1{public function show(){//创建P实例$p = new P();//创建M实例$m = new M();//将P注入到M中return $p->get($m);}}//客户端调用echo (new Client1())->show();
/demo2.php
<?phpnamespace w1205;//引入文件require 'P.php';require 'M.php';require 'C.php';//创建类 使用容器 把实例化代码放到容器中class Client2{//输出P Mpublic function show(P $p,M $m){return $p->get($m);}}//将类实例绑定到容器中 并实例化返回$c = new C();//将实例化代码绑定到容器$c->bind('P',function (){return new P();});$c->bind('M',function (){return new M();});$p = $c->M('P');$m = $c->M('M');echo (new Client2())->show($p,$m);
\inc\a.php
<?phpnamespace base\inc;class a{public function du(){return 'A类';}}
\inc\b.php
<?phpnamespace base\inc;class a{public function du(){return 'A类';}}
\inc\c.php
<?phpnamespace base\inc;class a{public function du(){return 'A类';}}
\auto.php
<?php//自动加载技术spl_autoload_register(function ($className){$path = str_replace('\\', '/', $className);require dirname(__DIR__) . DIRECTORY_SEPARATOR .$path . '.php';});
\demo1.php
<?php//工厂模式 实例namespace base;//use外部类名use base\inc\a;use base\inc\b;use base\inc\c;//引入自动加载文件require __DIR__ . '\auto.php';//创建类class Travel1{private $vehicle;//构造方法public function __construct($v){//设置判断switch (strtolower($v)){case 'a':$this->vehicle = new a();break;case 'b':$this->vehicle = new b();break;case 'c':$this->vehicle = new c();}}//调用外部依赖对象public function t(){return $this->vehicle->du() .'装备';}}//调用echo (new Travel1('a'))->t(),'<hr>';echo (new Travel1('b'))->t(),'<hr>';echo (new Travel1('c'))->t(),'<hr>';
\demo2.php
<?php//工厂模式 实例namespace base;//use外部类名use base\inc\a;use base\inc\b;use base\inc\c;//引入自动加载文件require __DIR__ . '\auto.php';//工厂类class F{protected static $inst;public static function get($v){switch (strtolower($v)){case 'a':self::$inst =new a();break;case 'b':self::$inst =new b();break;case 'c':self::$inst =new c();}return self::$inst;}}//创建类class Travel2{private $vehicle;//构造方法public function __construct($v){$this->vehicle = F::get($v);}//// public function __construct($v)// {// //设置判断// switch (strtolower($v)){// case 'a':// $this->vehicle = new a();// break;// case 'b':// $this->vehicle = new b();// break;// case 'c':// $this->vehicle = new c();// }// }//调用外部依赖对象public function t(){return $this->vehicle->du() .'装备！';}}//调用echo (new Travel2('a'))->t(),'<hr>';echo (new Travel2('b'))->t(),'<hr>';echo (new Travel2('c'))->t(),'<hr>';
/demo3.php
<?phpnamespace base;//引用use base\incs\a;use base\incs\b;use base\incs\c;use base\incs\iV;require __DIR__ . '/auto.php';class demo3{private $vehicle;public function __construct(iV $vehicle){$this->vehicle = $vehicle;}public function travelModel(){return $this->vehicle->du() . '装备！!!';}}echo (new demo3(new a()))->travelModel(), '<br>';echo (new demo3(new b()))->travelModel(), '<br>';echo (new demo3(new c()))->travelModel(), '<br>';
手写
总结
单例模式：设置类中唯一实例 通过判断禁止出现一个类 多个实例
工厂模式：通过数据调入批量创建多个统一规范的类实例/对象
