// File: LoginHandler.java
// This servlet checks the username and password for validity.
// If the client fails the check, they are told that access is denied.
// If the client passes, that fact is recorded in their session object
// and they are immediately redirected to the original target (obtained
// from the Session object).
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class LoginHandler extends HttpServlet {
public void doPost(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
res.setContentType("text/html");
PrintWriter out = res.getWriter();
// Get the user's name and password
String name = req.getParameter("name");
String passwd = req.getParameter("passwd");
// Check the name and password for validity
if (!allowUser(name, passwd)) {
out.println("Access Denied");
out.println("Your login and password are invalid.
");
out.println("You may want to try again");
out.println("");
}
else {
// Valid login. Make a note in the session object.
HttpSession session = req.getSession(true);
session.putValue("logon.isDone", name); // just a marker object
// Try redirecting the client to the page he first tried to access
try {
String target = (String) session.getValue("login.target");
if (target != null)
res.sendRedirect(target);
return;
}
catch (Exception ignored) { }
// Couldn't redirect to the target. Redirect to the site's home page.
res.sendRedirect(req.getScheme() + "://" +
req.getServerName() + ":" + req.getServerPort());
}
}
protected boolean allowUser(String user, String passwd) {
return true; // trust everyone
}
}