Advanced Java: Cookies in Servlet.

*What is Cookies?

~A cookie is a small piece of information that is persisted between the multiple client requests.

*Method of Cookies.

~public void getName()

:-return the name of the Cookie The Name Cannot be change after Creation.

~public String getValue()

:-return the value of Cookie.

~public void setValue(String name)

:-Change the name of the Cookie.

~public void setValue(String Value)

:-Change the value of the Cookie.

~public void setDomain(String pattern)

:-This method sets the domain to which Cookies applies.

~public String getDomain()

:-This method gets the domain to which Cookie applies.

~public void setMaxAge(int expiry)

:-This method sets how mach time (in seconds) should elapse before the Cookie expires.If you don't set this the cookie will last only for the current session.

~public int getMaxAge()

:-This Method return the maximum age of the cookie ,specified in second,by Default,-1,indicating the cookie will persist until browser shutdown.

~public String getPath()

:-This method gets the path to which this Cookie applies.

~public void setpath(String uri)

:-This method sets the path to which this Cookie applies.if you don't specify a path the cookie is return for all URLS in the same directory as the current page as well as all subdirectories.

~public void setSecure(boolean flag)

:-This method sets the boolean indicating whether cookie should only be set over encrypted connection.

*Other methods required for using Cookies

~public void addZCookie(cookie ck)

:-method of httpServletResponse interface is used to add Cookie in response object.

~public Cookie[] getCookies()

:-Method of httpServletRequest is used to return all the Cookied Form the Browser.

*Constructor.

~Cookie()

:-Contructor a Cookie.

~Cookie(String name,String value)

:-Contruct a cookie with Specified name and value.

*Example:

index.html

<html>
<head></head>
<body>
<form action="servlet1" method="post">
Name:<input type="text" name="userName"/><br/>
<input type="submit" value="go"/>
</form>
</body
</html>

servlet1.java

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class servlet1 extends HttpServlet {

protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html");

PrintWriter out=response.getWriter();

String name=request.getParameter("userName");

Cookie ck=new Cookie("un",name);

response.addCookie(ck);

out.print("<form action='servlet2' method='post'>");

out.print("<input type='submit' value='go'>");

out.print("</form>");

out.close();

}
}

Servlet2.java

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(urlPatterns = {"/servlet2"})
public class servlet2 extends HttpServlet {

protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

response.setContentType("text/html");
PrintWriter out=response.getWriter();

Cookie ck[]=request.getCookies();
out.println("hellow"+ck[0].getValue());
out.close();

}
}

output