1. JSP implicit objects & directive elements
Lec - 35

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

3. Implicit Objects

4. Implicit Objects
Objects that can be used in scriplets & expressions without defining them before.
request
response
out
Session
application
config
pageContext
exception
page

5. Implicit Objects cont. request: javax.servlet.HttpServletRequest
request object that is the reason for the servlet to run
response: javax.servlet.HttpServletResponse
Response for the request
out: javax.servlet.jsp.JspWriter
Output stream writer

6. Example of Implicit Objects
web.jsp
If page = = web
index.jsp
controller
.jsp
If page = = java
java.jsp

7. Use of implicit objects
Example Code
Use of implicit objects

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

9. JSP Directives

10. JSP Directives
Used to convey special processing information about the page to JSP container
Enable programmer to:
Specify page settings
Include content from other resources
Specify custom-tag libraries

11. JSP Directives cont. Format JSP directives
directive {attribute=“val”}* %>
JSP directives
page: page {attribute=“val”}* %>
include: include {attribute=“val”}* %>
taglib: taglib {attribute=“val”}* %>

12. JSP page Directive

13. JSP page Directive
Give high level information about servlet that will result from JSP page
Can be used anywhere in the document
Can control
Which classes are imported
What class the servlet extends
What MIME type is generated
How multithreading is handled
If the servlet participates in session
Which page handles unexpected errors

14. JSP page Directive cont.
Defines attributes of the page
page {attribute=“val”}* %>
Some Attributes
language = “java”
extends = “package.class”
import = “package.*,package.class,…”
session = “true | false”
Info = “text”
contentType = “mimeType”
isThreadSafe = “true | false”
errorPage = “relativeURL”
isErrorPage = “true | false”
Language specifies what language
Directives provide global information that is conceptually valid independent of any specific request received by the JSP page.
Compile time information.

15. JSP page Directive cont.
Some example uses are:
To import the package like java.util
page import = “java.util.*”
info = “using util package” %>
To declare this page as an error page
page isErrorPage = “true” %>
To generate the excel spread sheet
page contentType =
“application/vnd.ms-excel” %>
Language specifies what language
Directives provide global information that is conceptually valid independent of any specific request received by the JSP page.
Compile time information.

16. JSP include Directive

17. JSP include Directive
Lets you include (reuse) navigation bars, tables and other elements in JSP page
You can include files at
Translation Time (by using include directives)
Request Time (by using Action elements)

18. Including Pages at Translation Time using include directive
Format
file=“relativeURL”%>
Purpose
To include a file in JSP document at the time document is translated into a servlet.
May contain JSP code that affect the main page such as response header settings etc.

19. use of include directive
Example Code
use of include directive

20. Generate Excel Spread-sheets by setting content type
Modify Last Example to
Generate Excel Spread-sheets
by setting content type

21. XML Syntax for Directives
<jsp:directive.directiveType attribute=“value” />
For example, the XML equivalent of
page import = “java.util.*” %> Is
<jsp:directive.page import=“java.util.*” />

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

23. JSP Life Cycle Methods

24. JSP Life Cycle Methods jspInit() _jspService() jspDestroy() Request
Response
_jspService()
jspDestroy()