1、 1 外文翻译 ENGLISHE： Develop Web application program using ASP the architecture that must first establish Web application. Now in application frequently with to have two: The architecture of C/S and the architecture of B/S. Client/server and customer end / server hold the architecture of C/S. The custo
2、mer / server structure of two floor. Customer / server ( Client/Server ) model is a kind of good software architecture, it is the one of best application pattern of network. From technology, see that it is a logic concept, denote will a application many tasks of decomposing difference carry out , co
3、mmon completion is entire to apply the function of task. On each network main computer of web site, resource ( hardware, software and data ) divide into step, is not balanced, under customer / server structure, without the client computer of resource through sending request to the server that has re
4、source , get resource request, so meet the resource distribution in network not balancedness. With this kind of structure, can synthesize various computers to cooperate with work, let it each can, realize the scale for the system of computer optimization ( Rightsizing ) with scale reduce to melt ( D
5、ownsizing ). Picture is as follows: It is most of to divide into computer network application into two, in which the resource and function that part supports many users to share , it is realized by server； Another part faces every user , is realized by client computer, also namely, client computer i
6、s usual to carry out proscenium function , realizes man-machine 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
7、 user that shared. For a computer, it can have double function , is being certain and momentary to carve to act as server , and again becomes client computer in another time. Customer / server type computer divide into two kinds, one side who offers service is called as server , asks one side of ser
8、vice to be called as customer. To be able to offer service, server one side must have certain hardware and corresponding server software； Also, customer one side must also have certain hardware and corresponding customer software. There must be a agreement between server and customer, both sides com
9、municate according to this agreement. Apply customer / server model in Internet service , the relation between 2 customer and server is not immutable. Some Internet node offers service on the one hand , also gets service on the other hand from other node； It is even in one time dialogue course, mutu
10、al 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 computer , is using put or mpu
11、t 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 minut
12、es: 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 appl
13、ication resident core , changeable business logic. Therefore its structure has become 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 ,
14、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
15、 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 leve
16、ls of structural development of Client/Server come to the three-layer 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 network to send request. The structure of Browser/Server is maximum to
17、 have simplified the work of client computer, on client computer, 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. 3 Under the three-layer architecture of Browser/Server, express layer ( Pres
18、entatioon ) , 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. Its task is to suggest by Web browser to th
19、e 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 computer accept the homepage file that passed , and show it in Web browser on. Second layer function layer: Have the Web server
20、 of the application function of program extension. In function layer contain the systematic handling of general affairs logic, locate in Web server end. Its task is the request concerning accepting user , need to be first conducted and corresponding to expand application program and database to carr
21、y 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: Databas
22、e server. In data layer contain systematic data handling logic, locate in database server end. Its 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
23、 been easy to see , the architecture of Browser/Server of three-layer is the handling of general affairs of the two levels of structure of Client/Server logic modular from the task of client computer in split , from the first floor of individual composition bear the pressure of its task and such cli
24、ent computer have alleviated greatly, distribute load balancedly and have given Web server, so from the structural change of Client/server of original two floor the structure of Browser/Server of three-layer. This kind of three-layer architecture following picture shows. This kind of structure not o
25、nly client computer from heavy burden and the requirement of performance that rises continuously for it in liberation come out , also defend technology people from heavy maintenance upgrading work in free oneself. Since client computer handles general affairs , logic partial minutes have given funct
26、ion server, make client computer right off slender a lot of, do not take the responsibility for handling complex calculation and data again visit etc. crucial general affairs, is responsible to show part, so, maintenance people do not rush about again for the maintenance work of program between ever
27、y client computer, and put major energy in the program on function server update work. Between this kind of three-layer structural layer and layer, the mutually independent change of any first floor does not affect the function of other layer. It has changed the defect of the two levels of architecture of Client/Server of tradition from foundation, it is the transform with deep once in application systematic architecture. The contrast of two architectures
