| With the development of Internet technologies, the different network application systems and their managements are becoming more and more complicated. Directory Service meet the needs of the network development by its hierarchical structure, object oriented data model, and extensible and distributed characteristics.By studying the Directory Service and its applications, the applications of the Directory Service is concluded, as the view from the combining Directory Service, the service of the network application and their managements. Based on comparing the advantages and disadvantages of Directory applications, a new application model, which intends to further combine applications systems with Directory is proposed. Then the model is designed and implemented with the developing Web Services technologies.Several cases and their implementations are introduced in this thesis. Finally, some security issues about Directory Applications are discussed. |