To print Hello with
name
Step
1- Design
JSP page
Step
2- Make another jsp page to get
the parameters (using forward Request Dispatcher)
<html>
<head>
<meta
http-equiv="Content-Type" content="text/html;
charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<%
String st=request.getParameter("txtName");
if(st=="")
{
getServletContext().getRequestDispatcher("/index.jsp").forward(request,
response);
}
else
{
getServletContext().getRequestDispatcher("/welcome.jsp").forward(request,response);
}
%>
</body>
</html>
Step
3- Make
another demo so that hello comes in front of the name you write in textfield
<head>
<meta http-equiv="Content-Type" content="text/html;
charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
Hello---> <%=request.getParameter("txtName")%>
</body>
</html>
Demo 2- To display image with text on the image as
well as below the image with the help of servlet chaining.
Step 1- Design the first jsp page.
Step2- Design second jsp page in which image is to
be displayed and store the image in images folder.
<html>
<head>
<title>Dispatcher
Sample</title>
</head>
<body>
<div align="center">
<br><br>
<table width="800"
border="0" cellspacing="0" cellpadding="0"
bgcolor="#FFFFFF">
<!-- Title row [Begin]
-->
<tr>
<td
colspan="2" height="500"
background="images/faculty.jpg" align="center" valign="middle">
<big><big><big>
<div
style="color:white;"> <b>Hello World</b></div>
</big></big></big>
</td>
</tr>
<!-- Title row [End] -->
<tr>
<!-- Left Image [Begin]
-->
<td
width="600" background="images/main.jpg"
align="center" valign="top"> </td>
<!-- Left Image [End]
-->
<td>
<table
border="0" width="100%">
<!-- Content Row
[Begin] -->
<!-- Content row
[End] -->
</table>
</td>
</tr>
<!-- Footer row [Begin]
-->
<tr>
<td
width="60"> </td>
<td bgcolor="#FFFFFF"
align="center" valign="middle">
<table
border="0">
<tr>
<td
colspan="2" valign="middle" align="left">
<div
style="color: gray;">
<small>Copyright©http://nancy@techdazzler.com</small>
</div>
</td>
</tr>
</table>
</td>
</tr>
<!-- Footer row [End] -->
</table>
</div>
</body>
</html>
Step 3- Make
a servlet to print hello name which we will be giving in text fied as
shown
Step 4- Click on submit and output is ….
Demo 3- Use of Request Dispatcher (using include)
Step1- Deign JSP page1 as login application and css
is used here
Step 2-
Put values
Step 3- Click
on submit and another jsp page is
opened.
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;
charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<h1 align="center">LOGIN DETAILS</h1>
<form action="index3.jsp">
<table border="3" align="center">
<% String
Name=request.getParameter("txtName");
String password=
request.getParameter("txtPass");
if(Name==""
&& password=="" )
{
getServletContext().getRequestDispatcher("/index3.jsp").include(request, response);
}
%>
<tbody>
<tr>
<td>Name</td>
<td><input
type="text" name="txtName" value="<%=Name
%>" readonly="readonly" /></td></tr>
<tr><td>Place</td>
<td><input
type="text" name="txtPlace" value=""
/></td></tr>
<tr>
<td>Age</td>
<td><input
type="text" name="txtAge" value=""
/></td></tr>
<tr><td>Qualification</td>
<td><input
type="text" name="txtQua" value=""
/></td>
</tr>
<tr>
<td
colspan="4" align="center">
<input
type="submit" value="Submit" />
</td>
</tr>
</tbody>
</table>
</form>
</body>
</html>
Step 4-
Fill information
Step 5- Click on
submit and see the information on next page
Step 6- Check that the information is travelling from
1 pg to another now fill again the leftover records
Step 7- Click
on add and you will get the final result
sendRedirect
The
method response.sendRedirect() is used to dispatch the request for another
servlet execution in servlet chaining. In this process, client or browser are
involved in request dispatching. Firstly, servlet send response along with send
redirect URL to the client and
client again send that request to the server back to execute another servlet in
servlet chaining. Here, all servets may or may not execute in same
server or they may be executed differently
and client is plays an important
role in dispatching thus servlet
chaining is slow. In this process we can communicate with multiple servers.
HttpServletResponse response;
response.setRedirect(/servlet.jsp);
Advantage:
servets may or may not execute in same server or they may be executed differently and client is involved in dispatching.
servets may or may not execute in same server or they may be executed differently and client is involved in dispatching.
Limitation:
Here, as first send
Redirect() goes to client then to url to execute
another servlet, so first servlet respond to client and client again redirects
the URL to execte the servlet.Thus it takes more time to redirect the request
URL for the servlet chaining.
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