基于bs模式的教務管理系統的設計與實現畢業設計外文翻譯(完整版)

　　

【正文】 與升級的成本和工作量，降低了用戶的總體成本(TCO)。傳統的C/S體系結構雖然采用的是開放模式，但這只是系統開發一級的開放性，在特定的應用中無論是Client端還是Server端都還需要特定的軟件支持。三層的Browser/Server體系結構具有許多傳統Client/Server體系結構不具備的優點，而且又緊密的結合了Internet/Intranet技術，是技術發展的大勢所趨，它把應用系統帶入了一個嶄新的發展時代。 使用簡單，界面友好：Client/Server用戶的界面是由客戶端軟件所決定的，其使用的方法和界面各不相同，每推廣一個Client/Server系統都要求用戶從頭學起，難以使用。這種結構不僅把客戶機從沉重的負擔和不斷對其提高的性能的要求中解放出來，也把技術維護人員從繁重的維護升級工作中解脫出來。 第二層　功能層：具有應用程序擴展功能的Web服務器。這種結構即被稱為B/S體系結構。有的Internet節點一方面提供服務，另一方面也從別的節點處獲得服務；甚至在一次對話過程中，雙方的角色也可能互換。采用這種結構能綜合各種計算機協同工作，各盡其能，實現對計算機系統的規模優化（Rightsizing）和規模縮小化(Downsizing)。指導教師評語： 2012年2月18日簽名： （手寫簽名） 注：請將該封面與附件裝訂成冊。客戶/服務器（Client/Server）模型是一種良好的軟件體系結構，是網絡的最佳應用模式之一。為了能夠提供服務，服務器一方必須具有一定的硬件和相應的服務器軟件；同樣，客戶一方也必須具有一定的硬件和相應的客戶軟件。因此其結構就變成了新的(Client應用+Server應用)/Server結構。 在Browser/Server三層體系結構下，表示層(Presentatioon)、功能層(Business Logic)、數據層(Data Service)被割成三個相對獨立的單元：第一層　表示層：Web瀏覽器。它的任務是接受Web服務器對數據庫操縱的請求，實現對數據庫查詢、修改、更新等功能，把運行結果提交給Web服務器。Browser/Server所采用的標準都是開放的、非專用的，是經過標準化組織所確定的而非單一廠商所制定，保證了其應用的通用性和跨平臺性。Browser/Server系統的三部分模塊各自相對獨立，其中一部分模塊改變時其它模塊不受影響，系統改進變得非常容易，且可以用不同廠家的產品來組成性能更佳的系統。它是軟件系統體系結構，通過它可以充分利用兩端硬件環境的優勢，將任務合理分配到Client端和Server端來實現，降低了系統的通訊開銷。B/S(Browser/Server)結構即瀏覽器和服務器結構。(3) 管理軟件主流技術。二者可分別稱為前臺程序與后臺程序。(3) C/S架構的劣勢是高昂的維護成本且投資大。所以客戶機越來越“瘦”，而服務器越來越“胖”是將來信息化發展的主流方向。(3) 應用服務器運行數據負荷較重。s task is to suggest by Web browser to the certain a Web server on network that service is asked , after verifying for user identity, Web server delivers needed homepage with HTTP agreement to customer end, client puter accept the homepage file that passed , and show it in Web browser on. Second layer function layer: Have the Web server of the application function of program extension. In function layer contain the systematic handling of general affairs logic, locate in Web server end. It39。 Customer application program operation can be called as customer puter on the own puter of user, in correspondence with database server, when needs carry out any operation for the data in database, customer program seeks server program voluntarily , and sends request to it, server program is regular as basis intends to make to reply, send to return result, application server operation data load is lighter. (2) Data store management function relatively transparent. In database application data store management function, is carried out respectively independently by server program and customer application program , is regular as proscenium application can violate , and usually those different( no matter is have known still unknown ) operations data, in server program, do not concentrate realization, for instance visit limits of authority, serial number can be repeated , must have customer talent establishment the rule order. It is these to own , for the last user that works on proscenium program is transparent , they need not be interest in ( can not usually also interfere ) the course of behind, can plete own all work. In the application of customer server configuration proscenium program not is very thin , troublesome matter is delivered to server and network. In the system of C/S take off , database can not bee public really , professionally more petent storehouse, it gets independent special management. (3) The inferior position of the configuration of C/S is high maintenance cost make investment just big. First, with the configuration of C/S, will select proper database platform to realize the genuine unification of database data, make the data synchronism that spreads in two lands plete deliver by database system go to manage, but the logically two operators of land will directly visit a same database to realize efficiently , have so some problems, if needs establishment the data synchronism of real time , the database server that must establish real time munication connection between two places and maintains two lands is online to run , network management staff will again want to defend and manage for customer end as server defends management , maintenance and plex tech support and the investment of this high needs have very high cost, maintenance task is measured. Secondly, the software of the structure of C/S of tradition need to develop the software of different edition according to the different system of operating system , is very rapid because of the renovation of product, price is working needs high with inefficient already do not meet. In JAVA step platform language appearance after, the configuration of B/S is more vigorous impact C/S , and forms threat and challenge for it. .The advantage of B/S configuration software (1) The Maintenance of inferior position and upgrading way are simple. Now upgrading and the improvement of software system more and more frequently, the product of the configuration of B/S embodies more convenient property obviously. For one a little a little bit big unit , if systematic administrator needs , between hundreds of 1000 even last puters round trip run , efficiency and workload is to can imagine, but the configuration of B/S software needs management server have been all right , all customer ends are browser only, need not do any maintenance at all. No matter the scale of user has , is what , has how many branch will not increase any workload of maintenance upgrading , is all to operate needs to aim at server to go on。s task is to accept the request that Web server controls for database, realization is inquired and modified for database , update etc. function, submit operation result to Web server. Careful analysis is been easy to see , the architecture of Browser/Server of threelayer is the handling of general affairs of the two levels of structure of Client/Server logic modular from the task of client puter in split , from the first floor of individual position bear the pressure of its task and such client puter have alleviated greatly, distribute load balancedly and have given Web server, so from the