At the same time, the people always at look for the better method of build up the Web application procedure, the module spreads in customer's machine/ server the realm。 JavaBeans and ActiveX were published the company to expand to apply the procedure developer for Java and Windows to use to come to develop the complicated procedure quickly by" the fast application procedure development"( RAD) tool。 These techniques make the expert in the some realm be able to write the module for the perpendicular application plait in the skill area, but the developer can go fetch the usage directly but need not control the expertise of this realm。
Be a kind of take module as the central development terrace, the JSP appeared。 It with the JavaBeans and Enterprise JavaBeans( EJB) module includes the model of the business and the data logic for foundation, provide a great deal of label and a script terraces to use to come to show in the HTML page from the contents of JavaBeans creation or send a present in return。 Because of the property that regards the module as the center of the JSP, it can drive Java and not the developer of Java uses equally。 Not the developer of Java can pass the JSP label( Tags) to use the JavaBeans that the deluxe developer of Java establish。 The developer of Java not only can establish and use the JavaBeans, but also can use the language of Java to come to control more accurately in the JSP page according to the expression logic of the first floor JavaBeans。
See now how JSP is handle claim of HTTP。 In basic claim model, a claim directly was send to JSP page in。 The code of JSP controls to carry on hour of the logic processing and module of JavaBeanses' hand over with each other, and the manifestation result in dynamic state bornly, mixing with the HTML page of the static state HTML code。 The Beans can be JavaBeans or module of EJBs。 Moreover, the more complicated claim model can see make from is request other JSP pages of the page call sign or Java Servlets。
The engine of JSP wants to chase the code of Java that the label of JSP, code of Java in the JSP page even all converts into the big piece together with the static state HTML contents actually。 These codes piece was organized the Java Servlet that customer can not see to go to by the engine of JSP, then the Servlet edits and translate them automatically byte code of Java。
Thus, the visitant that is the website requests a JSP page, under the condition of it is not knowing, an already born, the Servlet actual full general that prepared to edit and translate completes all works, very concealment but again and efficiently。 The Servlet is to edit and translate of, so the code of JSP in the web page does not need when the every time requests that page is explain。 The engine of JSP need to be edit and translate after Servlet the code end is modify only once, then this Servlet that editted and translate can be carry out。 The in view of the fact JSP engine auto is born to edit and translate the Servlet also, need not procedure member begins to edit and translate the code, so the JSP can bring vivid sex that function and fast developments need that you are efficiently。
Compared with the traditional CGI, the JSP has the equal advantage。 First, on the speed, the traditional procedure of CGI needs to use the standard importation of the system to output the equipments to carry out the dynamic state web page born, but the JSP is direct is mutually the connection with server。 And say for the CGI, each interview needs to add to add a progress to handle, the progress build up and destroy by burning constantly and will be a not small burden for calculator of be the server of Web。 The next in order, the JSP is specialized to develop but design for the Web of, its purpose is for building up according to the Web applied procedure, included the norm and the tool of a the whole set。 Use the technique of JSP can combine a lot of JSP pages to become a Web application procedure very expediently。