1. JSP Action Elements
Lec - 37

2. JSP Journey directive elements ………………………. scripting elements
JSP comments……………………………….
declarations …………………………………
expressions …………………………..……..
scriptlets………………………………
action elements
special JSP tags ………………………….….
implicit
objects

3. JSP Action Elements

4. JSP Action Elements Format Expressed using XML syntax
Opening tag <jsp:actionElement attribute=“value” … >
Body body
Closing tag </jsp:actionElement >
Empty tags without body
<jsp:actionElement attribute=“value” … />

5. JSP Action Elements cont.
Purpose
To work with JavaBeans
To include pages at request time
To forward request to another resource etc.

6. Some JSP Action Elements
To work with JavaBeans
<jsp:useBean />
<jsp:setProperty />
<jsp:getProperty />
To include resources at request time
<jsp:include />
To forward request to anther JSP or Servlet
<jsp:forward />
To work with applets
<jsp:plugin />
And many more….

7. Working with JavaBeans using JSP Action Elements

8. Working with JavaBeans using JSP action elements
JSP action elements also helps to work with JavaBeans
<jsp:useBean />
Makes a JavaBeans object available in a page
<jsp:setProperty />
Sets a JavaBeans property value
<jsp:getProperty />
Gets a JavaBeans property value

9. JSP useBean Action Element
jsp:useBean is being equivalent to building an object in scriptlet
<%
MyBean m = new MyBean();
%> OR
<jsp:useBean id = “m” scope = “page” class=“vu.MyBean ”/>

10. JSP setProperty Action Element
jsp:setProperty is being equivalent to following code of scriptlet
<%
m.setName(“ali”);
%> OR
<jsp:setProperty id = “m” property = “name”
value=“ali” />

11. JSP getProperty Action Element
jsp:getProperty is being equivalent to following code of scriptlet
<%
String name = m.getName();
out.println(name);
%> OR
<jsp:getProperty id = “m” property= “name” />

12. Sharing Beans & Object Scopes

13. Understanding page Scope
first.jsp
second
.jsp
third.jsp
request 1
request 1
or request 2
create
Values not available
MyBean m = new MyBean();
MyBean m
m.setName(“ali”);
[name = ali]
Page Context

14. Understanding request Scope
first.jsp
second
.jsp
third.jsp
fourth.jsp
request 1
request 1
request 2
create
values not available
values available
MyBean m
[name = ali]
ServletRequest

15. Understanding session Scope
first.jsp
second
.jsp
third.jsp
fourth.jsp
request 1
request 1
request 2
create
values available
values available
MyBean m
[name = ali]
HttpSession

16. Understanding application Scope
first.jsp
second
.jsp
third.jsp
fourth.jsp
request 1
request 1
request 2
create
values available
values available
MyBean m
[name = ali]
ServletContext

17. Different Object Scopes
Most visible
page
Objects may be accessed only within pages
where they are created
Least visible

18. Different Object Scopes
Most visible
Only within pages processing the request
in which they are created
request
page
Objects may be accessed only within pages
where they are created
Least visible

19. Different Object Scopes
Most visible
Only from pages belonging to same session
as the one in which they were created
session
Only within pages processing the request
in which they are created
request
page
Objects may be accessed only within pages
where they are created
Least visible

20. Different Object Scopes
Within all pages belonging to same
application
Most visible
application
Only from pages belonging to same session
as the one in which they were created
session
Only within pages processing the request
in which they are created
request
page
Objects may be accessed only within pages
where they are created
Least visible

21. Object Scopes session, request & page

22. Object Scopes session vs. application

23. More JSP Action Elements

24. JSP include Action Element cont.
jsp:include is being equivalent to following code of scriptlet
<%
RequestDispatcher rd = request.getRequestDispatcher(“one.jsp”);
rd.include(request, response);
%> OR
<jsp:include page = “one.jsp” flush= “true” />

25. JSP forward Action Element
To forward request to another resource
Format
<jsp:forward page=“one.jsp" />
Works similar to following code of scriptlet
<%
RequestDispatcher rd = request.getRequestDispatcher(“one.jsp”);
rd.forward(request, response);
%>
Notes
-You are not permitted to specify false for the flush attribute (until JSP 1.2)
-Don’t forget that trailing slash - XML syntax!