Login/Log Out sample application is Struts 2 problem

Login/Log Out sample application is Struts 2

what are the additional technologies used in order to

make a logged-out user unable to login back by using

back button of the browser ?

please give the sample开发者_JAVA百科 code also

when using struts 2 and its session invalidation is not giving the above mentioned result.

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use this scriptlet

response.setHeader("Cache-Control","no-cache"); //HTTP 1.1 
response.setHeader("Pragma","no-cache"); //HTTP 1.0 
response.setHeader("Cache-Control","no-store");
response.setDateHeader ("Expires", 0);