这种模式有另一种称呼：控制链模式。它主要由一系列对于某些命令的处理器构成，每个查询会在处理器构成的责任链中传递，在每个交汇点由处理器判断是否需要对它们进行响应与处理。每次的处理程序会在有处理器处理这些请求时暂停。
<?phpabstract class Responsibility { // 抽象责任角色 ???protected $next; // 下一个责任角色 ???public function setNext(Responsibility $l) { ???????$this->next = $l; ???????return $this; ???} ???abstract public function operate(); // 操作方法}class ResponsibilityA extends Responsibility { ???public function __construct() {} ???public function operate(){ ???????if (false == is_null($this->next)) { ???????????$this->next->operate(); ???????????echo ‘Res_A start‘."<br>"; ???????} ???}}class ResponsibilityB extends Responsibility { ???public function __construct() {} ???public function operate(){ ???????if (false == is_null($this->next)) { ???????????$this->next->operate(); ???????????echo ‘Res_B start‘; ???????} ???}}$res_a = new ResponsibilityA();$res_b = new ResponsibilityB();$res_a->setNext($res_b);$res_a->operate();//输出：Res_A startPHP设计模式 - 责任链模式
原文地址：https://www.cnblogs.com/taozi32/p/9226828.html