策略模式的出行旅游：

;    }}class TrainStrategy implementsTravelStrategy{    public function travelAlgorithm(){        echotravelbyTrain,

;    }}class BicycleStrategy implementsTravelStrategy{    public function travelAlgorithm(){        echotravelbyBicycle,

;    }}class PersonContext{    private$_strategy = null;    public function __construct(TravelStrategy$travel){        $this->_strategy=$travel;    }        public functionset TravelStrategy(TravelStrategy$travel){        $this->_strategy=$travel;    }        public function travel(){        return$this->_strategy->travelAlgorithm();    }}//乘坐火车旅行$person=newPersonContext(newTrainStrategy());$person->travel();//改骑自行车$person->setTravelStrategy(newBicycleStrategy());$person->travel();?>