Servlets, JSPs and Tags

3.16 Servlets, JSPs and Tags

3.16.1 Questions

1. What a CGI program does? What do the servlets provide?

2. What methods are not present in the Servlet interface?

a. destroy()

b. processRequest()

c. processResponse()

d. init()

3. Which are the parameters 535y249f of the HttpServlet's service method? For what are they used?

4. How many servlets of a particular class are loaded into the container? What does the container before it shuts down?

5. How is the form data stored in an HttpServletRequest?

6. Is it possible that two clients can process the service() method at the same time? What must be done in the service method concerning the common resources?

7. What session tracking is? Explain how it can be performed (mention at least 2 ways).

8. How is data kept in a session object?

9. Explain how the JSP page is processed? Is the generated servlet recreated each time a new client performs a first request? Why?

10. What syntax from the following ones is a correct syntax for an existing JSP scripting element:

a. <jsp:scriptlet> something </jsp:scriptlet>

b. <%- something >

c. <%= something %>

d. <-- something -->

e. <%! something %>

11. What is the difference between beans and custom tags:

a. beans are actions and custom tags are components

b. beans are components and custom tags are actions/handlers

c. there is no difference between beans and custom tags

12. What are the basic steps for implementing custom tags? What is a tag library descriptor? For what is needed?

13. How can you find an ancestor tag of a custom tag derived from BodyTagSupport, based on the class name of the ancestor tag? What happens if the tag is not found?

3.16.2 Problems

1. Write an HTTP servlet that responds to each request containing a given date with the day of the week for that date.

2. Write a small web application based on the JSP technology that is able to administer a list of users. The application should be able to:

a. present the list of available users

b. offer possibility to add a new user, to delete an existing one and to modify an existing one

3. Consider using Struts when implementing the web application

4. Write a custom tag that based on the current locale gets the language specific value for a given key (there are separate resource files containing key/value pairs for each supported language) Use this custom tag to add internationalization support to application from point 2.