世博会开始了，为了让游客更好的享受世博旅途，组委会决定做一个自助系统，由这个系统来管理世博中一些常用的资源，例如：志愿者，广播人员，武警，医务人员。游客进入系统后，系统要列出所管理的资源，然后游客选择自己需要的资源，系统就列出该资源的一些信息和服务，游客可以选择这些信息进行了解，或者服务获得帮助。当然有些资源的信息是不对游客开放的，这时候系统需要告知游客所访问的信息不能被访问。程序中出现的异常需要被捕获并做适当处理。-Expo begins, in order to allow tourists to better enjoy the journey Expo, the organizing committee decided to do a self-service system, from the Expo in this system to manage some common resources, such as: volunteers, broadcasters, armed police, medical personnel. Visitors entering the system, the system managed to list resources, and visitors to choose their resources, system will list some of the resource information and services, visitors can choose the information to know, or services for help. Of course, some resource information is not open to visitors, and this time the system need to tell tourists to visit the information can not be accessed. Process needs to be captured exception occurs and make the appropriate treatment.