計(jì)算機(jī)科學(xué)與技術(shù)--基于jsp技術(shù)的企業(yè)商品展示網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)-預(yù)覽頁(yè)
【正文】 sion of the 10 of the standard is introduced in September 1999 December and launched 11 specifications At present JSP12 standard is relatively new JSP20 standard drafts have e The JSP page from the html code and the Java code embedded them together Server in a page is client requests for these Java code after processed and then will generate the html page back to the client browser Java Serviette is JSP technology base and large Web applications development need Java Serviette and JSP cooperate to plete The JSP have Java technology simple to use fully objectoriented has the platformindependent characteristics and safe and reliable mainly to Inter all characteristics 1 The JSP technology strong ① A pilation and running around At this point more wonderful than PHP Java outside except system without doing any change code ② System multiplatform support Basically can in all platform of arbitrary environment development in random environment in any systematic deployment environment expansion Compared with the limitations of ASPPHP now is so obvious ③ Strong scalability From only a small can run the Jar file ServietteJSP by multiple servers to cluster and load balancing to apply for transaction processing sets message handling one server to countless servers Java shows a great vitality ④ Diversification and powerful development tools support It is like Java with ASP has many excellent development tools and many can get free and many of them have can smooth running on multiple platforms below 2 The JSP technology weakness ① The same with ASP Java is some advantages of its deadly problem It is due to the function in order to extreme crossplatform adjustable ability so dramatically increase the plexity of the product ② Java with running speed is acplished scaleup memoryresident so it in some cases by use of memory than it really is the number of users lowest performance to price On the other hand it also needs hard disk space to store a series of Java files and scaleup documents and corresponding The version files 3 The JSP nine builtin objects That session 5 out page context fit apply and above brief ⑴ The object That encapsulates the user information submitted by calling this object can obtain corresponding methods namely use the information encapsulation the object can retrieve the user submits information ⑵ To the customer request object dynamic response to send data to the client ⑶ Session object ① What is the session session object is a JSP builtin object it is in the first JSP page is loaded when pleted automatically create session period management From a client open browser and connects to the server start to customer closed end leave the server browser called a conversation When a customer visit a server may in the server connection between several pages repeatedly refresh a page the server shall through some way to know this is the same customers this needs session object ② The session object ID when a customers first visit to a JSP page on the server JSP engine generates a session object and assigned String types of ID JSP engine will also be the ID Numbers sent to the client stored in session Cookie such between the object and the customer established onetoone relationship When a customer and visit the connection to the server when the other pages no longer assigned to the customer new session object until customer closed the server browser session object of the customer and customers to cancel the session corresponding relation disappear When customers open the browser to connect to the server the server creates a new session object ⑷ Application object ① What is applied Server startup after the produced this apply object when a customer again place visited sites between each page browsing the object is the same apply until closed servers But with session is different all customers object is the same apply that all customers sharing the builtin apply object ② Apply object monly used method Public use void set Attribute String key specific Object Will Object specified Object parameter added to apply Object and the Object of an index added specified keyword The get Attribute String key specific Object must apply Object Gets the Object containing keywords ⑸ Out object Out an object is an output stream used to client output data Out of all kinds of data object is used to output ⑹ Cookie ① What is the Cookie Cookie is Web server saves in the user on the hard drive a text Cookie allows a Web site on the users puter store information and then returning them to it For example a Web site for every visitor may produce a unique ID and then with the form of Cookie files stored in each user machine If you are using IE browser visit Web you can see all stored in your hard disk Cookie They are most often storage place is c \ Windows \ cookies Window2021 is in in c \ Documents and Settings \ your user name \ cookies Cookie is with keyword key specific value the format to save shops record ② Create a Cookie object calls the Cookie object constructor can create Cookie Cookie object constructor has two string parameters name and Cookie values Cookie c new Cookie so John ③ The JSP if will Cookie object transferred to encapsulate good use of the client 5 add Cookie method Format 5 add Cookie c ④ Read
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