<?php

 header("content-type:text/html; charset=utf-8");

 /**

  * 包裹重量异常

  */

 class HeavyParcelException extends Exception {}

 /**

  * 包裹类

  */

 class Parcel {

         /**

          * 包裹寄送目的地地址

          */

         public $address;

         /**

          * 包裹重量

          */

         public $weight;

 }

 /**

  * 派送员

  */

 class Courier {

         /**

          * 运送

          */

         public function ship(Parcel $parcel) {

                 //check we have an address

                 //如果包裹的目的地为空

                 if(empty($parcel->address)) {

                         throw new Exception('address not Specified(未填写地址)!');

                 }   

                 //check the weight

                 //如果重量超过5

                 if($parcel->weight > 5) {

                         throw new HeavyParcelException('Parcel exceeds courier limit(包裹超过运送上限)!');

                 }   

                 //otherwise we're coll

                 return true;

         }

 }

 $myCourier = new Courier();

 $parcel = new Parcel();

 //add the address if we have it 为了测试这里不填写地址

 $parcel->weight = 7;

 try {

         $myCourier->ship($parcel);

         echo "parcel shipped";

 } catch (HeavyParcelException $e) {//捕获HeavyParcelException 不写这个异常的类型名字，就跑到普通Exception抛出去了

         echo "Parcel weight error(重量错误): " . $e->getMessage();

         //redirect them to choose another courier

 } catch (Exception $e) {

         echo "Someting went wrong(地址错误): " . $e->getMessage();

         //exit so we don't try to proceed any further

         exit;

 }

 echo '<br/>';

 $a = 123;

 echo $a;