Two aspects of theCookieManager
class can be customized, theCookiePolicy
and theCookieStore
.
For convenience,CookiePolicy
defines the following pre-defined policies for accepting cookies:
CookiePolicy.ACCEPT_ORIGINAL_SERVER
only accepts cookies from the original server.CookiePolicy.ACCEPT_ALL
accepts all cookies.- You can also define your own cookie policy by implementing the
CookiePolicy.ACCEPT_NONE
accepts no cookies.shouldAccept
method ofCookiePolicy
. You can then use thisCookiePolicy
by passing it to the multi-argumentCookieManager
constructor or by calling thesetCookiePolicy(cookiePolicy)
method to change an already existing cookie manager.The following is an example of a cookie policy that rejects cookies from domains that are on a blacklist, before applying the
CookiePolicy.ACCEPT_ORIGINAL_SERVER
policy:When you create aimport java.net.*; public class BlacklistCookiePolicy implements CookiePolicy { String[] blacklist; public BlacklistCookiePolicy(String[] list) { blacklist = list; } public boolean shouldAccept(URI uri, HttpCookie cookie) { String host; try { host = InetAddress.getByName(uri.getHost()).getCanonicalHostName(); } catch (UnknownHostException e) { host = uri.getHost(); } for (int i=0; i<blacklist.length; i++) { if (HttpCookie.domainMatches(blacklist[i], host)) { return false; } } return CookiePolicy.ACCEPT_ORIGINAL_SERVER.shouldAccept(uri, cookie); } }BlacklistCookiePolicy
instance, you pass it an array of strings representing the domains that you do not want to accept cookies from. Then, you set thisBlacklistCookiePolicy
instance as the cookie policy for yourCookieManager
. For example:The sample code will not accept cookies from hosts such as the following:String[] list = new String[] { ".bar.com" }; CookieManager cm = new CookieManager(null, new BlacklistCookiePolicy(list)); CookieHandler.setDefault(cm);However, this sample code will accept cookies from hosts such as the following:foo.bar.com goo.bar.comy.com bar.com x.foo.bar.com
ACookieStore
is an interface that represents a storage area for cookies.CookieManager
adds the cookies to theCookieStore
for every HTTP response and retrieves cookies from theCookieStore
for every HTTP request.You can implement this interface to provide your own
CookieStore
and pass it to theCookieManager
during creation. You cannot set theCookieStore
after theCookieManager
instance has been created. However, you can get a reference to the cookie store by callingCookieManager.getCookieStore()
. Doing so can be useful as it enables you to leverage the default in-memoryCookieStore
implementation that is provided by Java SE and complement its functionality.For example, you might want to create a persistent cookie store that would save cookies so that they can be used even if the Java Virtual Machine is restarted. Your implementation would work similar to the following:
The following is an incomplete example of this cookie store. This example shows you how to leverage the Java SE default in-memory cookie store and how you might extend its functionality.
- Any cookies that were previously saved are read in.
- During runtime, cookies are stored and retrieved from memory.
- Cookies are written out to persistent storage before exiting.
import java.net.*; import java.util.*; public class PersistentCookieStore implements CookieStore, Runnable { CookieStore store; public PersistentCookieStore() { // get the default in memory cookie store store = new CookieManager().getCookieStore(); // todo: read in cookies from persistant storage // and add them store // add a shutdown hook to write out the in memory cookies Runtime.getRuntime().addShutdownHook(new Thread(this)); } public void run() { // todo: write cookies in store to persistent storage } public void add(URI uri, HttpCookie cookie) { store.add(uri, cookie); } public List<HttpCookie> get(URI uri) { return store.get(uri); } public List<HttpCookie> getCookies() { return store.getCookies(); } public List<URI> getURIs() { return store.getURIs(); } public boolean remove(URI uri, HttpCookie cookie) { return store.remove(uri, cookie); } public boolean removeAll() { return store.removeAll(); } }