What is Multitiered Application? 出自sun對寵物商店例子的綜述文檔?
Partitioning a design into tiers allows designers to choose the appropriate technology for a given situation. The Java Pet Store demo, illustrates how its design is divided into multiple tiers.
使用分層的方式來進行設計,可以使設計者針對具體的情況使用合適 的技術。這個Java 寵物商店的例子展示了如何把一個設計分成多層結構。
The Client tier is often the only part of the application the user sees. The Java Pet Store demo Client tier consists of a browser displaying web pages generated from JSP pages in the Web tier. An administrator interface uses a spreadsheet client, such as StarOffice software, to communicate with the Web Tier XML messages. The Client tier communicates with other tiers through defined interfaces. 客戶層通常是用戶唯一可以看到的應用程序的部分。這個寵物商店例子 的客戶層是一個瀏覽器,它負責顯示Web層中JSP頁產生的web頁面。一個 管理員接口可以使用一個spreadsheet客戶端(例如StarOffice軟件)來 和Web層交換XML消息。客戶層通過定義好的接口和其他層交互。
The Web tier performs web-related processing, such as serving HTML, instantiating web page templates, and formatting JSP pages for display. Some objects within the Web tier act as proxies to components in the Enterprise JavaBeans components tier. Web層負責Web相關的處理,比如提供HTML服務,產生web頁面的模板的實作, 格式化JSP頁面來顯示。Web層中有一些物件可以作為EJB組件層中組件的 代理。
The Enterprise JavaBeans components tier is responsible for any processing involving Enterprise JavaBeans components. Enterprise JavaBeans components contain the business logic of the Java Pet Store demo, such as processing orders. EJB components also represent the model objects of the Java Pet Store demo, including Account and placed Orders. EJB組件層負責任何與EJB組件相關的處理。EJB組件中包含這個Java寵物商店 的商業邏輯,比如處理訂單。EJB組件也含有這個Java寵物商店的物件模型, 包括賬目和處理過的訂單。
Stand-alone clients and web applications in the Web tier can use Enterprise JavaBeans components hosted by the Enterprise JavaBeans components tier. The Java Pet Store demo demonstrates the proper use of Enterprise JavaBeans components. 單機版客戶端和網絡層中的web應用都可以使用EJB組件層中的EJB組件。這個 Java寵物商店的例子展示了如何恰當地使用EJB組件。
The Enterprise Information System (EIS) tier provides a layer of software that maps existing data and application resources into the design of a J2EE application in an implementation-neutral way. The EIS tier can also access applications of other organizations or businesses, providing seamless business-to-business integration. 企業信息系統(EIS)層提供了一層軟件,以一種與實現無關的方式把已存在 的數據和應用資源一起映射到一個J2EE應用程序的設計之中。EIS層通過B2B的 無縫集成使得其它的組織或商業機構也可以對其進行使用。
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