JSP (Java Server Pages) Lecture # 4 Breif detail lecture about the JSP with example code the tutorial thing such as how to create, deploy etc etc

1. IMRAN DAUD
FOUNDATION UNIVERSITY
INSTITUTE OF MANAGEMENT AND
COMPUTER SCIENCES
Imran Daud
FUIMCS
Web Engineering
JSP

2. Intro to JSP
 Sun‟s Solution for developing dynamic websites.
 Server side scripting support for creating database
driven web applications.
 Web file always has „.jsp‟ extension.
 Insert java code into JSP file.
 On receiving request, JSP pages are loaded into
server memory for its execution.
 JSP Services are efficient and client is served in short
period of time.

3. Web-Server for JSP
 Number of web-servers are available.
 Apache TomCat
 WebSphere
 GalssFish
 etc

4. Setup NetBeans
 Start NetBeans
 Goto File->New Project…

5. Name & Location for Project

6. Choose Web-Server

7. Install New Web-Server

8. Installation and Login Details
First Install
required
web-server.
Give server
location
Username &
Password

9. We use Already Installed with NetBeans

12. Test Web-Server
 Run jsp file to test server by clicking green play
button.

13. JSP Tags
 <% (scriptless)
 <@ (directive page, include and taglib)
 <%-- (comment)

14. JSP Tags
 Directives
In the directives we can import packages, define error handling
pages or the session information of the JSP page.
 Declarations
This tag is used for defining the functions and variables to be used
in the JSP.
 Scriplets
In this tag we can insert any amount of valid java code and these
codes are placed in _jspService method by the JSP engine.
 Expressions
We can use this tag to output any data on the generated page. These
data are automatically converted to string and printed on the output
stream

15. Directive
<%@directive attribute="value" %>
 Where directive may be:
 page: page is used to provide the information about it.
Example: <%@page language="java" %>
 include: include is used to include a file in the JSP page.
Example: <%@ include file="/header.jsp" %>
 taglib: taglib is used to use the custom tags in the JSP pages
(custom tags allows us to defined our own tags).
Example: <%@ taglib uri="tlds/taglib.tld" prefix="mytag" %>

16. Attributes can be
 language="java"
This tells the server that the page is using the java language. Current JSP specification supports
only java language.
Example: <%@page language="java" %>
 extends="mypackage.myclass"
This attribute is used when we want to extend any class. We can use comma(,) to import more
than one packages.
Example: <%@page language="java" import="java.sql.*,mypackage.myclass" %>
 session="true"
When this value is true session data is available to the JSP page otherwise not. By default this
value is true.
Example: <%@page language="java" session="true" %>
 errorPage="error.jsp"
errorPage is used to handle the un-handled exceptions in the page.
Example: <%@page language="java" session="true" errorPage="error.jsp" %>
 contentType="text/html;charset=ISO-8859-1"
Use this attribute to set the mime type and character set of the JSP.
Example: <%@page language="java" session="true" contentType="text/html;charset=ISO-
8859-1" %>

17. Adding Scriptless
 <% opening tag
 %> closing tag
 To print message<% =“Hello World” %>
 To print <% = new java.util.Date() %>

18. JSP Declarations
 you must use the <%! and %> sequences to enclose
your declarations.
<%!
Date theDate = new Date();
Date getDate() {
out.println( "In getDate() method");
return theDate;
}
%>
Hello! The time is now <%= getDate() %>

19. Practice
 Make website counter…….

20. Declaration and Website Counter
<%!
 static int i=0;
 private int getCount(){
 return ++i;
 }
%>
<%=getCount()%>

21. Variables in Scriptless
 request:
request represents the clients request and is a subclass of HttpServletRequest. Use
this variable to retrieve the data submitted along the request.
Example:
<%
//java codes
String userName=null;
userName=request.getParameter("userName");
%>
 response:
response is subclass of HttpServletResponse.
 session:
session represents the HTTP session object associated with the request.
 out:
out is an object of output stream and is used to send any output to the client.

22. Handling „Request‟
 Steps
 Make index page with „form‟ containing username and
password.
 Use post or get method within form tag.
 Make two buttons submit and rest.
 Handle request in another jsp page.
 Methods to use are:
 Request
 Pagecontext(to redirect page)

23. Request methods
 very useful pre-defined variable is "request".
 It is of type javax.servlet.http.HttpServletRequest
 <%
request.getRemoteHoste(); or
request.getRemoteAddr();
 %>

24. JSP Session
 Associate any data with session by using .
 As long as session is maintained with user data will
be accessible on any page of website.
 Session object is associated with each user visiting
that website.
 Example: Associate username with session with
website of three pages.

25. How to Mix Scriptless and HTML

26. Import package
 <%@page import="java.util.*" %>
 <HTML>
 <BODY>
<% System.out.println( "Evaluating date now" );
Date date = new Date();
 %>
 Hello! The time is now
 <%= date %>
 </BODY>
 </HTML>

27. JSP Beans
 JSP introduces another organized way to retrieve
form data (but also supports other functionalities).
 That is by introducing bean.(This is not full beans)
 Define java with settter and
getter functions.

28. Bean Proporties
 i) It has a public no-args constructor
 ii) It has 'set' and 'get' methods for its properties.
 iii) It may have any general functions.

29. Steps in Creating JSP Beans
 Create html page with form data by setting action
page.
 Create java class with setter and getter function with
same name as defined in form fccccdcx.
 Create JSP page that will handle request data with
following tags.
 <jsp:useBean id=“mybean” class=“package.className"
scope="session"/>
 <jsp:setProperty name="mybean" property="*" />
 Retrieve data by following command.
 <%=mybean.getPassword()%>

30. Scope of Bean
 Scope= “Page” (only in current page of page specified)
 Scope = “request” (within request)
 Scope = “session” (all pages)

31.  If we access parameter in third page using „request‟
object then it shows null value.
 But same can be accessed using session object, if
scope is set to session.
 Now we can also access parameter through „request‟
object with following command in 2nd page.
 <jsp:forward page="session.jsp" />
 Use following to include page in existing page
 <jsp:include = “page.jsp” flush = “false” />

32. Quiz
 Use beans to make website counter……

33. Tag Libraries
 Also known as custom tags defined by user.
 Use to initiate any custom action.
 Custom actions include form processing, accessing
databases and other enterprise services such as email
and directories, and flow control.

34. Features of Custom Tags
 They can be customized via attributes passed from the calling
page.
 They have access to all the objects available to JSP pages.
 They can modify the response generated by the calling page.
 They can communicate with each other. You can create and
initialize a JavaBeans component, create a variable that refers
to that bean in one tag, and then use the bean in another tag.
 They can be nested within one another, allowing for complex
interactions within a JSP page.

35. Custom Tags
 Declare Tag Libraries
 <%@ taglib uri="/tlt" prefix="tlt" %>
 „Uri‟ attribute refers to a URI that uniquely identifies the tag
library.
 The prefix attribute distinguishes tags provided by a given tag
library from those provided by other tag libraries.

36. Steps
To define a tag, you need to:
 First declare the tags in a tag library
descriptor(TLD).
 Develop a tag handler and helper classes for the tag.

37. Tag Handler
Tag Handler
 Tag handler object is invoked by jsp container to
evaluate custom tag.
 This tag handler is java file with all custom actions
defined in it.
 We only use overridden functions

38. Classes to Import for handler
 TagSupport
 SimpleTagSupport

39. Tag Library Descriptor (TLD)

40. How to ?
 Create New File Tag Library Descriptor.
 Create Tag Handler file.
 Set functionality in tag handler. (once tag handler file is created
it automatically will write basic tags in TLD file).
 Call custom tag using following
 <%@taglib uri="mytld" prefix="mytag" %>
 <mytag:mytaghandler/>

41. Database
 Pre-Req:
 MySQL Server
 MySQL Workbench
 Create Database with table and attributes.
 WAMP Server
 Important
 Include SQL Library in Library folder before stating to
implement your project.

42. Steps to follow
 Import SQL Package in JSP File
 <%@ page language="java" import="java.sql.*" %>
 Load MySQL Driver
 Class.forName("com.mysql.jdbc.Driver");
 Create Connection with SQL Server
 Connection c=DriverManager.getConnection("jdbc:mysql://
localhost:3300/mydb","root", "123");
 Statement s= c.createStatement();
 ResultSet
 Statement
 ResultSet rs=s.executeQuery("Select * from student");

43. Show Results
 while (rs.next())
 {
out.println(rs.getString("myfield")+"<br>");
}

44. JSTL Use
 JSTL Tags are used for
 Iteration and conditionals
 Tags for manipulating XML documents
 Internationalization tags
 SQL tags.

45. JSTL

46. JSTL Steps
 Add JSTL library by right clicking on library folder of
project.
 To use JSTL in JSP file use following
 <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"
%>

47. JSTL Core Tags

49. JSTL SQL Tags

51. JSTL Functions

52. JSTL Format Tags

53. Reference
 http://www.csl.mtu.edu/cs2321/
 Netbeans.org
 Roseindia.net
 Jsptut.com
 tutorialspoint.com/jsp