我们有三个类,Db,FileSystem,Session;实际业务需求要组合操作这三个类.
一.常规做法
class Db{ ???public function read($id) ???{ ???}}class FileSystem{ ???public function writeFile($file) ???{ ???}}class Session{ ???public function setSession($sessionName) ???{ ???}}// 实际逻辑class Logic{ ???protected $db; ???protected $file; ???protected $session; ???public function __construct() ???{ ???????$this->db = new Db(); ???????$this->file = new FileSystem(); ???????$this->session = new Session(); ???} ???public function handle($id) ???{ ???????if ($name = $this->db->read($id)) { ???????????$this->file->writeFile(md5($name) . ‘.txt‘); ???????????$this->session->setSession($id); ???????} ???}}$id = 11;$client = new Logic();$client->handle($id);
缺点:
Logic内部高度耦合了,Db,FileSystem,Session
如果这三个类的初始化条件变化,则需要修改Logic的构造方法.
二.参数依赖(类型提示,将新建关联类的放入调用处)
修改Logic代码如下:
class Logic{ ???protected $db; ???protected $file; ???protected $session; ???public function __construct(Db $db, FileSystem $file, Session $session) ???{ ???????$this->db = $db; ???????$this->file = $file; ???????$this->session = $session; ???} ???public function handle($id) ???{ ???????if ($name = $this->db->read($id)) { ???????????$this->file->writeFile(md5($name) . ‘.txt‘); ???????????$this->session->setSession($id); ???????} ???}}$id = 11;$db = new Db();$file = new FileSystem();$session = new Session();$client = new Logic($db, $file, $session);$client->handle($id);
优点:
实现了解耦
缺点:
业务变动,如果要更改Db类到MySql类或初始化条件变动,代码依然要改动.
ps:大部分的设计模式使用了该解耦方法.
三.容器
1.希望DB类，Session类，FileSystem类“拿来即用”，不用每次繁琐的初始化，比如写$db=new DB(arg1,arg2);这类语句。
2.希望DB等类型的对象是“全局”，在整个程序运行期间，随时可以调用。
3.调用DB等类型的程序员不用知道这个类太多的细节，甚至可以用一个字符串的别名来创建这样一个对象。
能够实现以上目标的就是IOC容器，可以把IOC容器简单的看成一个全局变量，并用关联数组把字符串和构造函数做绑定
// 容器class Container{ ???public $binds = array(); ???public function bind($abstract, $concreate) ???{ ???????$this->binds[$abstract] = $concreate; ???} ???public function make($abstract, $params = []) ???{ ???????return call_user_func_array($this->binds[$abstract], $params); ???}}// 绑定或注册$container = new Container();$container->bind(‘db‘, function () { ???return new Db();});$container->bind(‘file‘, function () { ???return new FileSystem();});$container->bind(‘session‘, function () { ???return new Session();});// 实际逻辑,容器依赖class Logic{ ???protected $db; ???protected $file; ???protected $session; ???public function __construct(Container $container) ???{ ???????$this->db = $container->make(‘db‘); ???????$this->file = $container->make(‘file‘); ???????$this->session = $container->make(‘session‘); ???} ???public function handle($id) ???{ ???????if ($name = $this->db->read($id)) { ???????????$this->file->writeFile(md5($name) . ‘.txt‘); ???????????$this->session->setSession($id); ???????} ???}}$id = 11;$logic = new Logic($container);$logic->handle($id);
本文参考自:https://www.cnblogs.com/sweng/p/6430374.html
php解耦的三种境界
原文地址：http://www.cnblogs.com/itfenqing/p/7819500.html