Static include
This is a process to include the content of a file into a jsp. The include file can
be a jsp, html or txt file. This inclusion happens during the conversion of jsp
into the servlet. This is required to avoid duplicate code in multiple jsp. If a
common task is required to be performed by a set of jsp files then that code can be
written in a file and that file can be included in the required jsp. This can be
done by using name of the include file into the file attribute of include
directive. This directive can be used in any place and any number of times in a
jsp.
Example:
<html>
<head>
</head>
<body>
<h1 align="center">From jsp</h1>
<%@ include file="./x.jsp"%>
<h1 align="center">From html</h1>
<%@ include file="./y.html"%>
<h1 align="center">From text</h1>
<%@ include file="./z.txt"%>
</body>
</html>
Forwarding request
Using <jsp:forward>
This tag transfers request available to a jsp to another page or a jsp. The
second page can use the request available to the first jsp. It also transfers
the execution control to the second page. The execution control never comes back
to the first jsp. Hence, the code present after this tag cannot execute.
Attribute
Page:- This contains name and path of forward page.
<jsp:forward page="./x.jsp"/>
Using <jsp:include>
This tag transfers request and execution control to another page or jsp to
include response of that page. The execution control comes back to the first jsp.
The first jsp provides response to the user by including response of second
page. A jsp can include response of any number of pages. The user gets response
from multiple pages as a single output.
Attribute
Page:- This contains name and path of the include page.
<jsp:include page="./x.jsp"/>
Using <jsp:param>
This tag creates a parameter in the request.This tag must be used as the sub tag
of <jsp:forward> or <jsp:include> tag.
It can be used to create multiple parameters in the request.When the request
gets transferred then the forward page or include page can use the parameter
created by this tag through getParameter() of the request.
Attribute
Name:- It contains name of the parameter to be created.
Value:- It contains value of the parameter.
Difference between jsp include and static include
JSP include
- This includes response of the page into
the jsp.
- This is called as request time inclusion.
- It can include only the response of a web
page.
- The web server generates different
servlets for each include page.
Static include
- This includes code of a file into the jsp.
- This is called as translation time
inclusion.
- This can include code of any type of file.
- The web server generates only one servlets
for all included file in current jsp.
Example:- To show how to use of forwarding
request in a application. The scenario is when the user provides his/her correct
credentials (accountno, pinno) into the textbox and click a submit button he/she
is redirected to the balance page showing the balance present in his/her account.
Creation of a context file
Create any folder in any drive as (E:\Jsp). Inside that folder store your .jsp
files. Give the Context path name as jsp and docBase as E:\Jsp, here docBase
means the total path where we are storing our .jsp files. These changes are done
in the server.xml file, which is present in (E:\Program Files\Apache Software
Foundation\Tomcat 6.0\conf) directory.
Table creation
First create an account table in Oracle and insert some data as below
create table account(accountno varchar(50),pinno int,balance int)
insert into account values('Raj',123,1000)
insert into account values('Ravi',456,2000)
insert into account values('Rahul',789,3000)
Creation of dsn (database source name)
Start-Control panel- Administrative Tools- Data Sources (ODBC)-go to system dsn
tab-click add button-select a driver for which you want to set up data source
(for Oracle- Oracle in XE)-select it and click finish-give any name in data
source name textbox-then click ok button.
Note:- Here Username=system, Password=pintu and Dsn name=dsn2
Account.html
<html>
<head>
<script language="javascript">
function validate(objForm){
if(objForm.t1.value.length==0){
alert("Please enter Account No!");
objForm.t1.focus();
return false;
}
if(objForm.p1.value.length==0){
alert("Please enter Pin No!");
objForm.p1.focus();
return false;
}
return true;
}
</script>
</head>
<body >
<form name ="objForm" action="./validate.jsp" method="post" onSubmit="return
validate(this)">
<table>
<tr>
<td><b>Account No.</b></td>
<td><input name="t1" type="text " /></td>
</tr>
<tr>
<td><b>Pin No.</b></td>
<td><input name="p1" type="password" /></td>
</tr>
</table>
<input type="submit" value="submit"/>
</form>
</body>
</html>
validate.jsp
<%@ page import="java.sql.*" %>
<%
String str1=request.getParameter("t1");
String str2=request.getParameter("p1");
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con=DriverManager.getConnection("jdbc:odbc:dsn2","system","pintu");
Statement stmt=con.createStatement();
ResultSet rs=stmt.executeQuery("select * from account where accountno='"+ str1
+"' and pinno="+str2 );
if(rs.next())
{
int b=rs.getInt("balance");
%>
<jsp:forward page="/balance.jsp">
<jsp:param name="pr" value="<%= b %>" />
</jsp:forward>
<%
}
else
{
%>
<html>
<body>
<h1>Invalid Account No/Pin No </h1>
<jsp:include page="Account.html" />
<%
}
%>
</body>
</html>
balance.jsp
<html>
<body>
<%
String str1=request.getParameter("t1");
String str2=request.getParameter("pr");
%>
<h1>Account balance of <font color='#663300'><%= str1 %></font> is <font
color='red'><%= str2 %></font> </h1>
</body>
</html>
Running the application
Run the tomcat then write the below line in the URL
http://localhost:8081/jsp/
Here jsp is the Context path, which we mentioned in the server.xml file, which
is present in (E:\Program Files\Apache Software Foundation\Tomcat 6.0\conf)
directory.
After giving the URL a set a listing will come, here only three appears As
Account.html, balance.jsp, validate.jsp. Click Account.html and provide the
correct credentials to know the balance.
![JSP.gif]()