COOKIES
We've already used Cookies indirectly through Sessions. While session data is stored
on the server side and only an index to the server-side data (the session ID)
is transmitted to the client, Cookies can also be used directly to store data
on the client side.
The
Servlet API provides the class javax.servlet.http.Cookie for a convenient
object-oriented representation of Cookies so you don't need to compose and
decompose Cookie and Set-Cookie HTTP headers yourself.
Example. Imagine an authentication Servlet
which receives a username and password from
a login form via doPost and verifies them against a central authentication
database. It then computes an authentiation string (e.g. a Base64-encoded
"user:password" combination, as used by HTTP Basic Authentication). This string is now put into a Cookie
and sent back to the client:
Cookie
authCookie = new Cookie("xyz-Auth", credentials);
authCookie.setVersion(1); authCookie.setDomain(".xyz.com");
res.addCookie(authCookie);
Request and Response Objects
throws
ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
// Print the
HTML header out.println("<HTML><HEAD><TITLE>") ;
out.println("Request info");
out.println("</TITLE></HEAD>");
// Print the
HTML body out.println("<BODY><H1>Request
info</H1><PRE>");
out.println("getCharacterEncoding: " +
request.getCharacterEncoding());
out.println("getContentLength:
" + request.getContentLength()); out.println("getContentType: "
+ request.getContentType()); out.println("getProtocol: " +
request.getProtocol()); out.println("getRemoteAddr: " +
request.getRemoteAddr()); out.println("getRemoteHost: " +
request.getRemoteHost());
Related Topics
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.