Require login servlet to go to other pages

Question

There are a million examples on the web that shows how to create a basic Java Login Servlet, where the user has to enter a username and password which gets verified by some data

Answer 1

when login is successful you can set a a value in session.setAttribute() and in all pages by using session.getAttribute() check if the value is present or not.If yes stay else go back to login page.

example

After login is successful do

    session.setAttribute("user","user");

Now eac and every page check
if(session.getAttribute("user")==null)
{
response.sendRedirect("loginpage");

}
else
{

//your codes
}