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php 容器实现

2026-02-28 08:05:05PHP

PHP 容器实现的核心概念

PHP 容器（Dependency Injection Container）是一种管理对象依赖关系的工具，通过自动解析和注入依赖来简化代码。以下是实现容器的关键方法：

基础容器实现

创建一个简单的容器类，包含绑定和解析功能：

class Container {
    protected $bindings = [];

    public function bind($abstract, $concrete) {
        $this->bindings[$abstract] = $concrete;
    }

    public function make($abstract) {
        if (!isset($this->bindings[$abstract])) {
            throw new Exception("No binding found for {$abstract}");
        }

        $concrete = $this->bindings[$abstract];

        if ($concrete instanceof Closure) {
            return $concrete($this);
        }

        return new $concrete;
    }
}

自动依赖解析

通过反射自动解析类的依赖：

public function resolve($class) {
    $reflector = new ReflectionClass($class);

    if (!$reflector->isInstantiable()) {
        throw new Exception("Class {$class} is not instantiable");
    }

    $constructor = $reflector->getConstructor();

    if (is_null($constructor)) {
        return new $class;
    }

    $parameters = $constructor->getParameters();
    $dependencies = $this->resolveDependencies($parameters);

    return $reflector->newInstanceArgs($dependencies);
}

protected function resolveDependencies($parameters) {
    $dependencies = [];

    foreach ($parameters as $parameter) {
        $dependency = $parameter->getClass();

        if (is_null($dependency)) {
            if ($parameter->isDefaultValueAvailable()) {
                $dependencies[] = $parameter->getDefaultValue();
            } else {
                throw new Exception("Cannot resolve dependency {$parameter->name}");
            }
        } else {
            $dependencies[] = $this->resolve($dependency->name);
        }
    }

    return $dependencies;
}

接口绑定实现

支持接口到具体类的绑定：

public function bindInterface($interface, $implementation) {
    $this->bind($interface, function($container) use ($implementation) {
        return $container->resolve($implementation);
    });
}

单例模式支持

确保某些类只实例化一次：

protected $instances = [];

public function singleton($abstract, $concrete) {
    $this->bind($abstract, function($container) use ($concrete) {
        if (!isset($this->instances[$abstract])) {
            $this->instances[$abstract] = $container->make($concrete);
        }
        return $this->instances[$abstract];
    });
}

实际使用示例

$container = new Container();
$container->bind('logger', FileLogger::class);
$container->singleton('db', Database::class);

$logger = $container->make('logger');
$db = $container->make('db');