In this example we shall show you how to make use of HttpCookie class, HttpCookie is used to implement the HTTP state management mechanism which specifies a way to create a stateful session with HTTP requests and responses.
Generally, HTTP request/response pairs are independent of each other. However, the state management mechanism enables clients and servers to exchange state information and put these pairs in a larger context, which is called a session. The state information used to create and maintain the session is called a cookie.
A cookie is a piece of data that can be stored in a browser’s cache. If you visit a web site and then revisit it, the cookie data can be used to identify you as a return visitor. Cookies enable state information, such as an online shopping cart, to be remembered. A cookie can be short term, holding data for a single web session, that is, until you close the browser, or a cookie can be longer term, holding data for a week or a year.
Let’s see the below example which shows how to obtain all Http Cookies when we connect to facebook.com and provides complete information about those cookies like max age, domain name, value path etc.
Example:
HttpCookieTest.java:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 | package com.jcg;import java.io.IOException;import java.net.CookieHandler;import java.net.CookieManager;import java.net.CookieStore;import java.net.HttpCookie;import java.net.URL;import java.net.URLConnection;import java.util.List;/** * @author ashraf * */public class HttpCookieTest { /** * @param args * @throws IOException */ public static void main(String[] args) throws IOException { //Create a default system-wide CookieManager CookieManager cookieManager = new CookieManager(); CookieHandler.setDefault(cookieManager); //Open a connection for the given URL URL url = new URL(urlString); URLConnection urlConnection = url.openConnection(); urlConnection.getContent(); //Get CookieStore which is the default internal in-memory CookieStore cookieStore = cookieManager.getCookieStore(); //Retrieve all stored HttpCookies from CookieStore List cookies = cookieStore.getCookies(); int cookieIdx = 0; //Iterate HttpCookie object for (HttpCookie ck : cookies) { System.out.println("------------------ Cookie." + ++cookieIdx + " ------------------"); //Get the cookie name System.out.println("Cookie name: " + ck.getName()); //Get the domain set for the cookie System.out.println("Domain: " + ck.getDomain()); //Get the max age of the cookie System.out.println("Max age: " + ck.getMaxAge()); //Get the path of the server System.out.println("Server path: " + ck.getPath()); //Get boolean if the cookie is being restricted to a secure protocol System.out.println("Is secured: " + ck.getSecure()); //Gets the value of the cookie System.out.println("Cookie value: " + ck.getValue()); //Gets the version of the protocol with which the given cookie is related. System.out.println("Cookie protocol version: " + ck.getVersion()); } }} |
Output:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | ------------------ Cookie.1 ------------------Cookie name: reg_fb_gateDomain: .facebook.comMax age: -1Server path: /Is secured: falseCookie value: https%3A%2F%2Ffanyv88.com%3A443%2Fhttps%2Fwww.facebook.com%2FCookie protocol version: 0------------------ Cookie.2 ------------------Cookie name: reg_fb_refDomain: .facebook.comMax age: -1Server path: /Is secured: falseCookie value: https%3A%2F%2Ffanyv88.com%3A443%2Fhttps%2Fwww.facebook.com%2FCookie protocol version: 0------------------ Cookie.3 ------------------Cookie name: datrDomain: .facebook.comMax age: 63071999Server path: /Is secured: falseCookie value: ElIxVBBVUE8ODDu-dVnn7FecCookie protocol version: 0 |
Explanation:
In the above example, we create and set a system-wide CookieManager using the following code:
1 2 | CookieManager cookieManager = new CookieManager();CookieHandler.setDefault(cookieManager); |
The first line calls the default CookieManager constructor to create a new CookieManager instance with a default cookie store and accept policy. The second line calls the static setDefault method of CookieHandler to set the system-wide handler.
After that, we open a connection with facebook.com to get all the available cookies. Finally, we retrieve all cookies from the cookie store using the below code then we print information about those cookies like max age, domain name, value path etc.
1 2 | CookieStore cookieStore = cookieManager.getCookieStore();List cookies = cookieStore.getCookies(); |
Tip
CookieStoreis the place where any accepted HTTP cookie is stored. If not specified when created, aCookieManagerinstance will use an internal in-memory implementation. This implementation is not persistent and only lives for the lifetime of the Java Virtual Machine. Users requiring a persistent store must implement their own store.- The default
CookiePolicyused byCookieManagerisCookiePolicy.ACCEPT_ORIGINAL_SERVER, which only accepts cookies from the original server. So, the Set-Cookie response from the server must have a “domain” attribute set, and it must match the domain of the host in the URL.
Download the Source Code of this example:
This was an example of how to use HttpCookie class.
You can download the full source code of this example here: java.net.HttpCookie Example Code
