Unit 5 ,Chapter : 8 Cookie
One Slide per Page Download
Six Slide per Page Download
Monthly Archives: March 2015
Cookie Attribute
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class CookieAttribute extends HttpServlet
{
public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException
{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
//create a cookie
Cookie c1=new Cookie("fname","mca4");
c1.setMaxAge(60*60);
c1.setComment("hi");
c1.setDomain("abc.com");
c1.setPath("/mca");
c1.setSecure(true);
c1.setVersion(1);
response.addCookie(c1);
out.println("Name = " + c1.getName() + "<br>");
out.println("Value = " + c1.getValue()+ "<br>");
out.println("Comment = " + c1.getComment()+ "<br>");
out.println("MaxAge = " + c1.getMaxAge()+ "<br>");
out.println("Domain " + c1.getDomain()+ "<br>");
out.println("Path = " + c1.getPath()+ "<br>");
out.println("Secure = " + c1.getSecure()+ "<br>"); //default value : false
out.println("Version = " + c1.getVersion()+ "<br>"); // default value : 0
}
}
Modifying Cookie Values: Tracking User Access Counts
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Ex3 extends HttpServlet
{
public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException ,IOException
{
res.setContentType("text/html");
PrintWriter out=res.getWriter();
String ac =CookieUtility.getCookieValue(req,"AC","0");
int i=Integer.parseInt(ac);
i=i+1;
out.println("visit counter : " + i);
CookieUtility.createCookie(res,"AC",String.valueOf(i),3600);
}
}
Using Cookies to Remember User Preferences
Ex2.java
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Ex2 extends HttpServlet
{
public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException ,IOException
{
res.setContentType("text/html");
PrintWriter out=res.getWriter();
String unm=CookieUtility.getCookieValue(req,"unm","");
String pwd=CookieUtility.getCookieValue(req,"pwd","");
out.println("<html><body><form action=Ex21>"+
"enter username <input type=text name=txtunm value="+unm+">"+
"<br> enter password : "+
"<input type=password name=pwd value="+pwd+"><br>"+
"<input type=submit value=ok></form></body></html>");
}
}
Ex21.java
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Ex21 extends HttpServlet
{
public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException ,IOException
{
res.setContentType("text/html");
PrintWriter out=res.getWriter();
String unm= req.getParameter("txtunm");
String pwd= req.getParameter("pwd");
CookieUtility.createCookie(res,"unm",unm,300);
CookieUtility.createCookie(res,"pwd",pwd,300);
}
}
Cookie to determine first time visitor using CookieUtility Class
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Ex1 extends HttpServlet
{
public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException ,IOException
{
res.setContentType("text/html");
PrintWriter out=res.getWriter();
String newu =CookieUtility.getCookieValue(req,"RV","No");
if(newu.equals("No"))
{
CookieUtility.createCookie(res,"RV","Yes",300);
out.println("Welcome to India");
}
else
{
out.println("welcome back");
}
}
}
CookieUtility Class
Here CookieUtility class is created to take advantage of reuseability concept.
Here in these class, we have two method:
1) To create a cookie -> createCookie() Method
2) To read particular cookie -> getCookieValue()
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class CookieUtility extends HttpServlet
{
public static String getCookieValue(HttpServletRequest req,String cn,String defaultvalue)
{
Cookie [] cr=req.getCookies();
if(cr != null)
{
for(int i=0;i<cr.length;i++)
{
if(cr[i].getName().equals(cn))
{
return cr[i].getValue();
}
}
}
return defaultvalue;
}
public static void createCookie(HttpServletResponse res,String cn,String cv,int age)
{
Cookie c1=new Cookie(cn,cv);
c1.setMaxAge(age);
res.addCookie(c1);
}
}
Cookie to determine first time visitor
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class RepeatVisitor extends HttpServlet
{
public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException
{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
boolean newu=true;
Cookie [] c=request.getCookies();
if(c!=null)
{
if(c[0].getName().equals("RV"))
{
for (int i=0;i<c.length;i++)
{
if (c[i].getName().equals("RV"))
{
newu=false;
}
}
}
}
if(newu)
{
Cookie c1=new Cookie("RV","Yes");
c1.setMaxAge(60*60);
response.addCookie(c1);
out.println("Welcome to India");
}
else
{
out.println("welcome back");
}
}
}
Retrieving all cookies from the Browser
Note :This will fetch cookies only set by current domain.
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class CookieDemo1 extends HttpServlet
{
public void doGet(HttpServletRequest req,HttpServletResponse res)
throws ServletException,IOException
{
Cookie[] cr = req.getCookies();
if (cr!=null)
{
for (int i=0;i<cr.length;i++)
{
out.println (cr[i].getName() + " : " + cr[i].getValue());
}
}
}
}
Creating a Cookie in a Servlet
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class CookieDemo extends HttpServlet
{
public void doGet(HttpServletRequest req,HttpServletResponse res)
throws ServletException,IOException
{
PrintWriter out = res.getWriter();
Cookie c1 = new Cookie("fname","mca");
c1.setMaxAge(3600); // Set cookie age otherwise it will create session level cookie
res.addCookie(c1);
out.println ("cookie created successfully");
}
}
Web Technology & Application Development – 2640002 