【文章內容簡介】 and display a from 0 to 9 string. In the string in the front and rear of the HTML code that some are through the text output. HTML HEAD TITLEJSP PAGE /TITLE /HEAD BODY %@ page language=java % %! String str=0。 % % for (int i=1。 i 10。 i++) { str = str + i。 } % JSP Before out。 P %= str % P JSP After out。 /BODY /HTML The JSP page can be divided into several parts for analysis. First is the JSP instructions. It describes the basic information of the page, such as the use of language, whether to maintain conversation status, whether to use cushion etc. The JSP instructions by % @ beginning, % over. In this example, directive % @ brief language = Java % simply defines this example is using Java language (at present, in the JSP specification in Java is the only support language). Next came the JSP statement. The JSP statement may be regarded as the definition of this level of variables and method of place. The JSP statement by %! Start, % over. If the cases of %! String STR = 0 。 % defines a String variable. In every statement behind must have a semicolon, just like in ordinary Java class declaration in the same member variables. Located in % and % between the code block is to describe the JSP page handling logic of Java code, such as the example shown the seas cycle. Finally, located in % = and % between code is called the JSP expression, such as the example of % = STR % below. The JSP expression provides a will JSP generated numerical embedded HTML pages of simple method. 2. The session state management The session state maintain is the Web application developers must face the problem. There are various ways can be used to solve this problem, if use Cookies, hidden form input domain, or directly to the URL in additional status information. Java Servlet provides a continuous effectively in multiple requests the conversation between objects, the object allows users to store and retrieve the session state information. The JSP also support Servlet of this concept. In the JSP from guidelines can see many relevant implied object instructions (implicit meaning is that these objects can directly referenced, do not need explicit statement, also do not need special code to create actually cases). For example that object, it is the HttpServletRequest a derived class. The object contains all the related current browser requests information, including Cookies, HTML form variables, etc. Session object is also such a hidden objects. This object in the first JSP page is loaded, and automatically created by related to that objects. The conversation with ASP object of similar, JSP session object for those who hope that through multiple pages to plete a affairs application is very useful. To illustrate the session object concrete application, next we use three pages more than a page of simulation Web application. The first page (q1. HTML) contain only a requirement to enter your user name HTML forms, the HTML code is as follows: HTML BODY FORM METHOD=POST ACTION= Please write your name： INPUT TYPE=TEXT NAME=thename INPUT TYPE=SUBMIT VALUE=SUBMIT /FORM /BODY /HTML The second page is a JSP page (q2. JSP), it through that object extraction in q1. HTML form thename value, it will be stored for name variable, then will the name value saved to the session objects. Session object is a name/value pairs set, here, name/value pairs of the name is thename, namely for name values of the value of the variable. Due in session during the session object is effective until, so here preserved variables on subsequent page as well. Q2. JSP another task is to ask the second question. Below is its code: HTML BODY %@ page language=java % %! String name=。 % % name = (thename)。 (thename, name)。 % What is your name： %= name % p FORM METHOD=POST ACTION= What do you want to eat? INPUT TYPE=TEXT NAME=food P INPUT TYPE=SUBMIT VALUE=SUBMIT /FORM /BODY /HTML The third page is a JSP page (percentile. JSP), main task is to show the qamp。a results. It from the value of the thename session object extraction and display it, prove the value in the first though page input, but through session object is maintained. Percentile. JSP another task is to extract the user input at the second page and displays it: HTML BODY %@ page language=java % %! String food=。 % % food = (food)。 String name = (String) (thename)。 % Your name is： %= name % P Your favorite food is： %= food % /BODY /HTML 3. Citing JavaBean ponents Based on a Java JavaBean is a kind of software ponent. In Web applications for the JSP integrated JavaBean ponent provides the perfect support. This support can not only shorten time (can use directly by test and trustworthy of existing ponents, to avoid the repeated development), but also for the JSP application has brought more scalability. JavaBean ponents can be used to execute plex puting tasks, or responsible and database of interaction and data extraction, etc. If we have three JavaBean, they respectively display news, stock price, weather conditions function, they create contain all these three functions of Web page only need to instantiate the three Bean, using HTML forms will be they in turn positioning is ok. To illustrate the JSP JavaBean application environment, we created a name of TaxRate Bean. It has two attributes that our Product (products) and Rate (tax). Two set separately used to set the two properties, and two the get method is used to extract the two attributes. In practical applications,