Filters are mainly used to determine whether a user logs in to prevent direct access to the webpage in the application for submission.
Filter class writing,
Package 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 .*;
Import com.tar Ena. CRM. domain. admin. Manager;
Public class loginfilter extends httpservlet implements filter ...{
Public void dofilter (servletrequest request, servletresponse response, filterchain chain) throws ioexception, servletexception ...{
Httpservletrequest Req = (httpservletrequest) request;
Httpservletresponse res = (httpservletresponse) response;
If (req. getsession (). getattribute ("manager") = NULL )...{
Res. sendredirect ("/CRM/CORE/login. jsp ");
} Else
Chain. dofilter (request, response );
}
Public void Init (filterconfig arg0) throws servletexception ...{
}
}
In web. xml:
<URL-pattern>/CORE/adminmanage/* </url-pattern> filter a directory
Or:
<URL-pattern>/CORE/adminmanage/test. jsp </url-pattern> filter a specific webpage
<Filter>
<Filter-Name> setlog </filter-Name>
<Filter-class> filter. loginfilter </filter-class>
</Filter>
<Filter-mapping>
<Filter-Name> setlog </filter-Name>
<URL-pattern>/CORE/adminmanage/* </url-pattern>
</Filter-mapping>
