【正文】 護(hù)管理，又要對(duì)客戶端維護(hù)和管理，這需要高昂的投 資和復(fù)雜的技術(shù)支持，維護(hù)成本很高，維護(hù)任務(wù)量大。在 JAVA這樣的跨平臺(tái)語(yǔ)言出現(xiàn)之后， B/S 架構(gòu)更是猛烈沖擊 C/S，并對(duì)其形成威脅和挑戰(zhàn)。 目前，軟件系統(tǒng)的改進(jìn)和升級(jí)越來(lái)越頻繁， B/S 架構(gòu)的產(chǎn)品明顯體現(xiàn)著更為方便的特性。無(wú)論用戶的規(guī)模有多大，有多少分支機(jī)構(gòu)都不會(huì)增加任何維護(hù)升級(jí)的工作量，所有的操作只需要針對(duì)服務(wù)器進(jìn)行；如果是異地，只需要把服務(wù)器連接專網(wǎng)即可，實(shí)現(xiàn)遠(yuǎn)程維護(hù)、升級(jí)和共享。今后，軟件升級(jí)和維護(hù)會(huì)越來(lái)越容易，而使用起來(lái)會(huì)越來(lái)越簡(jiǎn)單，這對(duì)用戶人力、物力、時(shí)間、費(fèi)用的節(jié)省是顯而易見(jiàn)的，驚人的。 (2)成本降低，選擇更多。 現(xiàn)在的趨勢(shì)是凡使用B/S 架構(gòu)的應(yīng)用管理軟件，只需安裝在 Linux 服務(wù)器上即可，而且安全性高。 比如說(shuō)很多人每天上 “新浪”網(wǎng)，只要安裝了瀏覽器就可以了，并不需要了解“新浪”的服務(wù)器用的是什么操作系統(tǒng)，而事實(shí)上大部分網(wǎng)站確實(shí)沒(méi)有使用 windows操作系統(tǒng)，但用戶的電腦本身安裝的大部分是 windows 操作系統(tǒng)。 由于 B/S 架構(gòu)管理軟件只安裝在服務(wù)器端 (Server)上，網(wǎng)絡(luò)管理人員只需要管理服務(wù)器就行了，用戶界面主要事務(wù)邏輯在服務(wù)器 (Server)端完全通過(guò) WWW 瀏覽器實(shí)現(xiàn)，極少部分事務(wù)邏輯在前端 (Browser)實(shí)現(xiàn)，所有的客戶端只有瀏覽器，網(wǎng)絡(luò)管理人員只需要做硬件維護(hù)。因此，許多單位都備有數(shù)據(jù)庫(kù)存儲(chǔ)服務(wù)器，以防萬(wàn)一。 Another part faces every user , is realized by client puter, also namely, client puter is usual to carry out proscenium function , realizes manmachine interaction through user interface , or is the application program of specific conducted user. And server usually carries out the function of backstage supporter , manages the outside request concerning seting up, accepting and replying user that shared. For a puter, it can have double function , is being certain and momentary to carve to act as server , and again bees client puter in another time. Customer / server type puter divide into two kinds, one side who offers service is called as server , asks one side of service to be called as customer. To be able to offer service, server one side must have certain hardware and corresponding server software。 It is even in one time dialogue course, mutual role also exchanges probably. As in carry out file transmission , if be called as one side who offers file server, is called as one side who gets file customer, when using get or mget order since another node takes file, can think that what self use and it is client puter , is using put or mput order to another node dispatch file can again think the machine that used self is server. Multilayer customer / server structure Along with the development of enterprise application, recently, have again arisen a kind of new multilayer architecture, it applies customer end to divide into two minutes: Customer application and server apply. Customer application is the part of original customer application , is another and partial to have been transfered to server to apply. New customer application takes the responsibility for user interface and simple regular business logic and new server application resident core , changeable business logic. Therefore its structure has bee new ( Client application + Server application )/Server structure. Following picture shows: This kind of structure has solved traditional Client/Server can expand problem, have reduced customer end business logic , and have reduced the requirement of customer end for hardware. At the same time because of a lot of business logic concentrations have gone to unitary application server on, the maintenance work of application system had been also concentrated together, have eliminated the problem in the traditional structure of Client/Server that software distributes. This kind of structure is called as the architecture of B/S. Browser/Server and browser / server hold the architecture of B/S. On essence, Browser/Server is also a kind of structure of Client/Server, it is a kind of from the traditional two levels of structural development of Client/Server e to the threelayer structural special case of Client/Server that applied on Web. In the system of Browser/Server, user can pass through browser to a lot of servers that spread on work to send request. The structure of Browser/Server is maximum to have simplified the work of client puter, on client puter, need to install and deploy few customer end software only , server will bear more work, for database visit and apply program carry out will in server finish. Under the threelayer architecture of Browser/Server, express layer ( Presentatioon ) , function layer ( Business Logic ) , data layer ( Data Service ) have been cut the unit of 3 relative independences: It is the first layer of to express layer: Web browser. In expressing layer contain system show logic, locate in customer end. It39。s task is the request concerning accepting user , need to be first conducted and corresponding to expand application program and database to carry out connection , passes through the waies such as SQL to database server to put forward data handling to apply for, then etc. database server the result of handling data submit to Web server, deliver again by Web server to return customer end. The number of plies of 3th according to layer: Database server. In data layer contain systematic data handling logic, locate in database server end. It39。s application is often for special purpose. It is lower to develop and defend cost: It need to be implemented on all client puters that the application of Client/Server must develop the customer end software for special purpose, no matter installation and disposition escalate still, have wasted manpower and material resources maximumly. The application of Browser/Server need in customer end have general browser , defend and escalate to work in server end go on , need not carry out any change as customer holds , have reduced the cost of development and maintenance so greatly. It is simple to use , interface friendly: The interface of the user of Client/Server is decided by customer end software, interface and the method of its use are not identical each, per popularize a system of Client/Server ask user study from the beginning, is hard to use. The interface of the user of Browser/Server is unified on browser, browser is easy to use , interface friendly, must not study use again other software, the use of a Lao Yong Yi that has solved user problem. Customer end detumescence: The customer end of Client/Server has the funct