Laravel中使用Ioc容器的singleton方法和bind方法创建实例的区别 - DipForLL的博客 - CSDN博客

安宇雨 - 随手采集
2019-04-06 05:57:07
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它们两个都是返回一个类的实例，不同的是singleton是单例模式，而bind是每次返回一个新的实例，看下面的两个例子。

1.Ioc容器bind方法

<?phprequire __DIR__.'/../bootstrap/autoload.php';  class tanteng {     public $name; }   $container = new Illuminate\Container\Container(); $container->bind('tanteng'); $instance = $container->make('tanteng'); $instance->name = 'tanteng'; $instance2 = $container->make('tanteng'); $instance2->name = 'tuntun';  echo $instance->name.' '.$instance2->name;

输出的结果：

tanteng tuntun

结论：

通过bind方法创建实例不是单例模式，而是创建新的实例。

2.Ioc容器singleton方法

<?phprequire __DIR__.'/../bootstrap/autoload.php';  class single {     public $value; }  $container = new Illuminate\Container\Container();  $container->singleton('single'); $instance3 = $container->make('single'); $instance4 = $container->make('single');   $instance3->value = 'aaaa'; $instance4->value = 'bbbb';   echo $instance3->value.' '.$instance4->value;

输出结果：

bbbb bbbb

结论：

使用singleton创建实例使用的是单例模式，每次返回同一个实例。

以上代码可以放在public下，如test.php运行。

再看框架底层代码：

public function singleton($abstract, $concrete = null){    $this->bind($abstract, $concrete, true);}

发现singleton方法其实也是调用bind方法，只是最后一个参数是true，表示单例模式。框架源代码：Illuminate/Container/Container.php

附上bind()方法

public function bind($abstract, $concrete = null, $shared = false)    {        $abstract = $this->normalize($abstract);         $concrete = $this->normalize($concrete);         // If the given types are actually an array, we will assume an alias is being        // defined and will grab this "real" abstract class name and register this        // alias with the container so that it can be used as a shortcut for it.        if (is_array($abstract)) {            list($abstract, $alias) = $this->extractAlias($abstract);             $this->alias($abstract, $alias);        }         // If no concrete type was given, we will simply set the concrete type to the        // abstract type. After that, the concrete type to be registered as shared        // without being forced to state their classes in both of the parameters.        $this->dropStaleInstances($abstract);         if (is_null($concrete)) {            $concrete = $abstract;        }         // If the factory is not a Closure, it means it is just a class name which is        // bound into this container to the abstract type and we will just wrap it        // up inside its own Closure to give us more convenience when extending.        if (! $concrete instanceof Closure) {            $concrete = $this->getClosure($abstract, $concrete);        }         $this->bindings[$abstract] = compact('concrete', 'shared');         // If the abstract type was already resolved in this container we'll fire the        // rebound listener so that any objects which have already gotten resolved        // can have their copy of the object updated via the listener callbacks.        if ($this->resolved($abstract)) {            $this->rebound($abstract);        }    }

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创建于: 2019-04-06 05:57:06
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