.jsp中的登录系统

Question

I have a login.jsp page which contains a login form. Once logged in the user will be taken to index.jsp and this index.jsp should know which user is logged in. If the user refreshes the page he will stay logged in and not taken back to the login.jsp . So there need to be some sort of session.

UPDATE Session Management

Answer 1

Once the user has logged in you should add something to the session, such as the user name, to indicate the user is logged in.

You might then like to add a servlet filter that detects whether a request is coming from someone who is logged on by checking for a user name on the session. If the person is not logged on your filter can send the request to your login.jsp instead of the actual page they requested. Using a filter like this means you don't have to write any logon detection and redirecting in your JSP pages.

Finally you might want to provide a logout option which kills the session with session.invalidate();

Answer 2

Use request.getSession() to begin a new session. There you can save(using setAttribute method) your own Java objects which will be there during the whole session.

Answer 3

This can be done by using the session object:

<%
   String name = "testme";
   session.setAttribute( "theName", name ); //write as an attribute in the session object
%>

and some time later you can do:

<% String name= session.getAttribute("theName")%> // retireve the attribute from the session

check here for a simple introduction: http://www.jsptut.com/Sessions.jsp