Java Qiao Xiaosong-Clear the webpage cache using the filter Filter

Package www. csdn. dbshop. filter; import Java. io. ioexception; import javax. servlet. filter; import javax. servlet. filterchain; import javax. servlet. filterconfig; import javax. servlet. servletexception; import javax. servlet. servletrequest; import javax. servlet. servletresponse; import javax. servlet. HTTP. httpservletresponse; public class cachefilter implements filter {public void destroy () {system. out. println ("cache filter ------ destruction operation");} public void dofilter (servletrequest request, servletresponse response, filterchain chain) throws ioexception, servletexception {system. out. println ("Clear cache ................ "); // response object httpservletresponse res = (httpservletresponse) response; // set the expiration time of the webpage. Once it expires, you must call res again on the server. setdateheader ("expires",-1); // cache-control specifies the cache mechanism that the request and response should follow. No-Cache indicates that the request or response message cannot be cached by Res. setheader ("cache-control", "No-Cache"); // used to disable the browser from calling the page content from the local cache, once the page is set, Res cannot be called out from the cache. setheader ("Pragma", "No-Cache"); // release the chain. dofilter (request, Res);} public void Init (filterconfig) throws servletexception {system. out. println ("initialize data ----- clear cache ");}}