详解Laravel服务容器的优势

$obj1 = $container->make('class1', 'class2');
 
$obj2 = $container->make('class3', 'class4');

$obj1 = new class1(new class2());
 
$obj2 = new class3(new class4());

 
class EmailService{
    public function send(){
        //todo 发送邮件方法
    }
}
//如果任何地方要发邮件我们就复制下面这两行代码
 
$emailService = new EmailService();
 
$emailService->send();

$this->app->bind('emailService', function ($app) {
    return new EmailService();
});
//如果任何地方要发邮件我们就复制下面这两行代码
$emailService = app('emailService');
$emailService->send();

//只需要改这一个地方
$this->app->bind('emailService', function ($app) {
    return new SupperEmailService();
});

//使用到EamilSerice类的每个地方都要更改
$emailService = new SupperEmailService();
$emailService->send();

class SupperEamilService{
    //创建静态私有的变量保存该类对象
    static private $instance;
    //防止直接创建对象
    private function __construct(){
        
    }
    //防止克隆对象
    private function __clone(){

    }
    static public function getInstance(){
        //判断$instance是否是Uni的对象
        //没有则创建
        if (!self::$instance instanceof self) {
            self::$instance = new self();
        }
        return self::$instance;
    }
    //发送邮件方法
    public function send(){

    }

}

$emailService=SupperEmailService::getInstance();
$emailService->send();

//只需要把bind改成singleton
$this->app->singleton('emailService', function ($app) {
    return new SupperEmailService();
});

<?PHP
interface TrafficTool{
    public function Go();
}
class Train implements TrafficTool{
    public function go(){
        echo "train....";
    }

}
class Leg implements TrafficTool{
    public function go(){
        echo "leg..";
    }
}
class Traveller{
    
    protected $_trafficTool;
    public function __construct(TrafficTool $trafficTool){
        $this->_trafficTool = $trafficTool;
    }
    public function visitTibet() {
        $this->_trafficTool->go();
    }

}

<?php
$train = new Train();
$tra = new Traveller($train);
$tra->visitTibet();

<?php
namespace App\Providers;
use Laravel\Lumen\Providers\EventServiceProvider as ServiceProvider;
class RepositoryServiceProvider extends ServiceProvider{
    public function reGISter(){
        //在服务容器中绑定类
        $this->app->bind( 'TrafficTool', 'Train');
        $this->app->bind('Traveller', 'Traveller');
    }
}

<?php
// 实例化对象
$tra = app()->make('Traveller');
$tra->visitTibet();