Java Filter to redirect users who are not logged in to login page
Solution 1
After response.sendRedirect("/login.jsp");
do return;
.
Solution 2
I believe that you should either invoke sendRedirect OR doFilter. E.g.
if (requiresLogin)
response.sendRedirect("/login.jsp");
else
chain.doFilter(req,resp);
Shamik
I am a learner. Currently Tech Lead @twilio. Know a thing or two about python and java development.
Updated on July 09, 2022Comments
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Shamik almost 2 years
I was trying to make a filter to stop users who are not logged in from accessing certain pages.For this i made a filter class with the following
doFilter
methodHttpServletRequest request = (HttpServletRequest) req; HttpServletResponse response = (HttpServletResponse) res; String url = request.getRequestURI(); boolean allowedRequest = false; System.out.println(url); if(urlList.contains(url)) { allowedRequest = true; System.out.println("in list"); } if (!allowedRequest) { Object o = request.getSession().getAttribute("UserInfo"); if (null == o) { System.out.println("Hey i am in"); response.sendRedirect("/login.jsp"); } } chain.doFilter(req, res); } // end of doFilter
To allow the pages which doesnot need the user to be logged in i created an arraylist url-list in init()
Now a very strange stupid thing is happening. suppose i have two pages home.jsp and dcr.jsp. When i try to access home.jsp without logging in the i am successfully redirected to login.jsp but when i am trying to access dcr.jsp it is not redirected although it enters the loop if(null == o) which i can understand because i am getting that line printed in console.THis is the output that i get in the server This is the output that i get in the server
/dcrmaintenance.jsp Hey i am in
Which tells me that the null == o was true.
The page dcr.jsp accesses a session object and since the user is not logged in it is getting java.lang.NullPointerException as expected but i cannot understand why is the redirection not taking place even after entering the loop.If someone can pt out where i am making a mistake it would be appreciated.
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Shamik about 12 yearsI didnt have any other filter.The other solution worked.But i will check out how i can use security constraints! thanks.