/*前端控制器的主要组成部分及功能如下:
1、入口文件类controller;(对这个系统的调用都是从这个文件开始的,也相当于一个控制中心，对所有相关的类进行调用)
2、应用程序配置信息类applicationhelper;(用于获取应用程序所需的配置信息)
3、命令类解释器commandresolver;(根据用户请求调用相应的命令类)
4、命令类command;(调用用户请求信息类和业务逻辑,还可以调用视图文件)
整个系统的调用步骤大概就是：
1、获取程序所需的配置信息
2、获取命令类
3、执行命令类
前端控制器与命令模式对比，在我看来二者基本没什么区别，原理大致相同。前端控制器的代码及注解如下：*/namespace woo\controller;//入口文件类class controller {private $applicationhelper;private function __construct (); static function run(){$instance = new controller();$instance->init();$instance->handlerequest();
} function init(){ //获取程序所需的配置信息 $applicationhelper = applicationhelper::instance();$applicationhelper->init();
} function handlerequest(){ //获取并执行命令类$request = new \woo\controller\request();$cmd_r = new \woo\command\commandresolver();$cmd = $cmd_r->getcommand($request);$cmd->execute($request);
}
}//获取应用程序配置信息class applicationhelper {private static $instance;private $config = /tmp/data/woo_options.xml; //配置信息保存的文件private function __construct (){} static function instance(){if(!self::$instance){
selff::$instance = new self();
}return self::$instance;
} function init(){$dsn = \woo\base\applicatonregistry::getdsn(); if(!is_null($dsn)){return;
}$this->getoptions();
} private function getoptions(){$this->ensure(file_exists($this->config),conld not find options file); $options = simplexml_load_file($this->config);print get_class($options);$dsn = (string)$options->dsn;$this->ensure($dsn,no dsn found);
\woo\base\applicationregistry::setdsn($dsn); //配置信息将被缓存到一个注册表类中
//设置其他值
} private function ensure($expr,$message){if(!$expr){throw new \woo\base\appexception($message);
}
}
}//用户请求信息类 class request {private $properties;private $feedback =array();function __construct(){$this->init();
\woo\base\requestregistry::setrequest($this);
} function init(){if(isset($_server['request_method'])){$this->properties = $_request;return;
}foreach($_server['argv'] as $arg){if(strpos($arg,'=')){list($key,$val) = explode(=,$arg);$this->setproperty($key,$val);
}
}
} function getproperty($key){if(isset($this->properties[$key]){return $this->properties[$key];
}
} function setproperty($key,$val){$this->properties[$key] = $val;
} function addfeedback($msg){array_push($this->feedback,$msg);
} function getfeedback(){return $this->feedback;
}function getfeedbackstring($separator=\n){return implode($separator,$this->feedback);
}
}
namespace woo\command;//命令解释器 class commandresolver{private static $base_cmd;private static $default_cmd; function __construct (){if(!self::$base_cmd){//命令类的基类,这个主要将使用反射来检查找到的命令类是否是继承了它self::$base_cmd = new \reflectionclass(\woo\command\command);
self::$default_cmd = new defaultcommand(); //默认的命令类，当找不到相应的命令类时将调用它 }
} //获取命令类function getcommand(\woo\controller\request $request){$cmd = $request->getproperty('cmd');$sep = directory_separator; //代表/if(!$cmd){return self::$default_cmd;
}$cmd = str_replace(array('.',$sep),,$cmd);$filepath = woo{$sep}command{$sep}{$cmd}.php; //命令类的文件路径$classname = woo\\command\\{$cmd}; //类名if(file_exists($filepath)){
@require_once($filepath);if(class_exists($classname)){$cmd_class = new reflectionclass($classname);if($cmd_class->issubclassof(self::$base_cmd)){return $cmd_class->newinstance(); //实例化命令类} else {$request->addfeedback(command '$cmd' is not a command);
}
}
}$request->addfeedback(command '$cmd' not found);return clone self::$default_cmd;
}
}//命令类abstract class command{final function __construct(){}function execute(\woo\controller\request $request){$this->doexecute($request);
}abstract function doexecute(\woo\controller\request $request);
}class defaultcommand extends command{function doexecute(\woo\controller\request $request){$request->addfeedback(welcome to woo);include(woo/view/main.php);
}
}//客户端require(woo/controller/controller.php);
\woo\controller\controller::run();
以上就是前端控制器模式实例详解的详细内容。