How to prevent Tomcat creating separate sessions for domain.com and www.domain.com?

Our web app is deployed on Tomcat. If users visit http://domain.com and http://www.domain.com, they get two different JSESSIONID cookies, and thus two separate sessions, one for domain.开发者_如何转开发com and one for www.domain.com. This causes all sorts of problems if they start doing something in a session on www.domain.com, and then later they are redirected to domain.com.

Is there any way to force Tomcat to just use one JSESSIONID for both domain.com and www.domain.com?

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You could try to use mod_rewrite and redirect all domain.com users to www.domain.com.

If your Tomcat is not behind Apache, you can always write a simple servlet filter to do the same.

Also, have a look here: https://serverfault.com/questions/93995/configuring-apache-tomcat-mod-jk-and-mod-rewrite-to-serve-up-tomcat-from-top-le