PHP核心技术——反射

反射:

• 反射指在PHP运行状态中，扩展分析PHP程序，导出或提取出关于类、方法、属性、参数等的详细信息，包括注释。这种动态获取信息以及动态调用对象方法的功能称为反射API

class person{ ???public $name; ???public $gender; ???public function say(){ ???????echo $this->name,"\tis",$this->gender,"\r\n"; ???} ???public function __set($name,$value){ ???????echo "Setting $name to $value \r\n"; ???????$this->$name=$value; ???} ???public function __get($name){ ???????if (!isset($this->$name)) { ???????????echo '末设置'; ???????????$this->$name="正在为你设置默认值"; ???????} ???????return $this->$name; ???}}$student = new person();$student -> name='Tom';$student -> gender='male';$student ->age=24;//获取对象属性列表$reflect = new ReflectionObject($student);$props = $reflect -> getProperties();foreach ($props as $prop) { ???print $prop -> getName()."\n";}//获取对象方法列表$m = $reflect -> getMethods();foreach ($m as $prop) { ???print $prop -> getName()."\n";}//返回对象属性的关联数组var_dump(get_object_vars($student));//类属性var_dump(get_class_vars(get_class($student)));//返回由类的方法名组成的数组var_dump(get_class_methods(get_class($student)));//获取对象属性列表所属的类echo get_class($student);

• 反射API的功能显然更强大，甚至能还原这个类的原型，包括方法的访问权限,代码如下

//反射获取类的原型$obj = new ReflectionClass('person');$className = $obj -> getName();$Methods = $Properties = array();foreach ($obj -> getProperties() as $v) { ???$Properties[$v -> getName()] = $v;}foreach ($obj ->getMethods() as $v) { ???$Methods[$v -> getName()] = $v;}echo "class {$className}\n{\n";is_array($Properties)&&ksort($Properties);foreach ($Properties as $k => $v) { ???echo "\t"; ???echo $v -> isPublic()?'public':'',$v -> isPrivate()?'private':'', ???$v -> isProtected()?'protected':'', ???$v -> isStatic()?'static':''; ???echo "\t{$k}\n";}echo "\n";if (is_array($Methods)) ksort($Methods);foreach ($Methods as $k => $v) { ???echo "\tfunction {$k}(){}\n";}echo "}\n";

• 反射可以探知类的内部结构，可以用它做hook实现插件功能或者是做动态代理

class mysql{ ???function connect($db){ ???????echo "连接到数据库${db[0]}\r\n"; ???}}class sqlproxy{ ???private $target; ???function __construct($tar){ ???????$this -> target[] = new $tar(); ???} ???function __call($name,$args){ ???????foreach ($this -> target as $obj) { ???????????$r = new ReflectionClass($obj); ???????????if ($method = $r -> getMethod($name)) { ???????????????if ($method -> isPublic() && !$method -> isAbstract()) { ???????????????????echo "方法前拦截记录LOG\r\n"; ???????????????????$method -> invoke($obj,$args); ???????????????????echo "方法前拦截\r\n"; ???????????????} ???????????} ???????} ???}}$obj = new sqlproxy('mysql');$obj -> connect('member');

• 真正的操作类是mysql类，但是sqlproxy类实现了根据动态传入参数，代替实际的类运行，并且在方法运行前后进行拦截，并且动态地改变类中的方法和属性。这就是简单的动态代理。

参考资料

• [PHP核心技术与最佳实践]

PHP核心技术——反射

原文地址：https://www.cnblogs.com/geniusrun/p/10607736.html