Cookie
public class Cookie
extends java.lang.Object
implements java.lang.Cloneable
Creates a cookie, a small amount of information sent by a servlet to a Web browser,
saved by the browser, and later sent back to the server. A cookie's value can
uniquely identify a client, so cookies are commonly used for session
management.
A cookie has a name, a single value, and optional attributes such as a comment,
path and domain qualifiers, a maximum age, and a version number. Some Web
browsers have bugs in how they handle the optional attributes, so use them
sparingly to improve the interoperability of your servlets.
The servlet sends cookies to the browser by using the HttpServletResponse.addCookie(javax.servlet.http.Cookie)
method, which adds fields to HTTP response headers to send cookies to the
browser, one at a time. The browser is expected to support 20 cookies for each
Web server, 300 cookies total, and may limit cookie size to 4 KB each.
The browser returns cookies to the servlet by adding fields to HTTP request
headers. Cookies can be retrieved from a request by using the HttpServletRequest.getCookies() method. Several
cookies might have the same name but different path attributes.
Cookies affect the caching of the Web pages that use them. HTTP 1.0 does not cache
pages that use cookies created with this class. This class does not support the
cache control defined with HTTP 1.1.
Register.java
package view;
import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Register extends HttpServlet
{
protected void processRequest(HttpServletRequest request, HttpServletResponse
response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try
{
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet Register</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Please fill the details:</h1>");
out.println("<form action=Validate method=GET>");
out.println("<table>" +
"<tr>" +
"<td>Name</td><td><input type=text name=name></input></td></tr>" +
"<tr>" +
"<td>Surname</td><td><input type=text
name=surname></input></td></tr>" +
"<tr>" +
"<td>City</td><td><input type=text name=city></input></td></tr>" +
"<tr>" +
"<td>State</td><td><input type=text name=state></input></td></tr>"
+
"<tr>" +
"<td></td><td><input type=reset
value=Reset></input>  <input type=submit Value=Submit></input></td>" +
"</tr>" +
"</table>");
out.println("</form>");
out.println("</body>");
out.println("</html>");
}
finally{
out.close();
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
processRequest(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
processRequest(request, response);
}
public String getServletInfo()
{
return "Short description";
}
}
show.java
package view;
import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Show extends HttpServlet
{
protected void processRequest(HttpServletRequest request, HttpServletResponse
response)
throws ServletException, IOException
{
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
Cookie[] c=request.getCookies();
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet Show</title>");
out.println("</head>");
out.println("<body>");
if(c.length == 1)
{
out.println("<h4>The information you enter only lasts " +
"10 seconds in history.</h4>");
out.println("Please <a href=\"Register\">Click Here</a> to submit
again.");
}
else
{
out.println("<h3>Your Information is:</h3>");
out.println("<table>" +
"<tr>" +
"<td>Name</td><td>"+c[1].getName()+"</tr>" +
"<tr>" +
"<td>Surname</td><td>"+c[1].getValue()+"</td></tr>" +
"<tr>" +
"<td>City</td><td>"+c[2].getName()+"</td></tr>" +
"<tr>" +
"<td>State</td><td>"+c[2].getValue()+"</td></tr>" +
"</table>");
out.println("<br /><a href=\"Show\">Click Here</a> to refresh page.");
out.println("<h4>The information you enter only lasts " +
"10 seconds in history.</h4>");
out.println("Please <a href=\"Register\">Click Here</a> to submit
again.");
}
out.println("</body>");
out.println("</html>");
} finally {
out.close();
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
processRequest(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
processRequest(request, response);
}
public String getServletInfo()
{
return "Short description";
}
}
Validate.java
package control;
import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Validate extends HttpServlet {
protected void processRequest(HttpServletRequest request, HttpServletResponse
response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
String name=request.getParameter("name");
String surname=request.getParameter("surname");
String city=request.getParameter("city");
String state=request.getParameter("state");
Cookie c1=new Cookie(name,surname);
Cookie c2=new Cookie(city,state);
c1.setMaxAge(10);
c2.setMaxAge(10);
response.addCookie(c1);
response.addCookie(c2);
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet Validate</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Information Stored sucessfully!!!</h1>");
out.println("<br />Please <a href=\"Show\">Click Here</a> to go to next
page.");
out.println("<br /> Page will be expired in 10 seconds.");
out.println("</body>");
out.println("</html>");
} finally {
out.close();
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
processRequest(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
processRequest(request, response);
}
public String getServletInfo()
{
return "Short description";
}
}
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