package servlets;
import java.io.IOException;
import java.io.PrintStream;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionBindingListener;
public class ExampleServlet extends HttpServlet {
public void init(ServletConfig config) {
System.out.println("Example servlet has started up.");
}
public void destroy() {
System.out.println("Example servlet is shutting down.");
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
System.out.println("ExampleServlet got GET request.");
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
System.out.println("ExampleServlet got POST request.");
String userName = request.getParameter("name");
String password = request.getParameter("password");
String nextPage = request.getParameter("nextPage");
String nextServlet = request.getParameter("nextServlet");
PrintStream out = new PrintStream(response.getOutputStream());
if (nextServlet != null) {
request.getRequestDispatcher("image").forward(request, response);
return;
}
if (nextPage == null) {
out.println("Results");
out.println("Results of Log InYou have successfully logged into the system!");
session.setAttribute("user", new User(userName));
out.println("
Click here to get to the next page.
");
out.println("Click here to go to the next servlet.
");
} else {
out.println("Your password is not correct!
");
}
out.println("");
} else {
out.println("Next page");
User user = (User)request.getSession().getAttribute("user");
if (user != null) {
out.println("I remember who you are " + user.getName() + ".
");
} else {
out.println("I seem to have forgotten you.
");
}
out.println("");
}
}
}
class User implements HttpSessionBindingListener {
private String userName;
public User(String userName) {
this.userName = userName;
}
public String getName() {
return userName;
}
public void valueBound(HttpSessionBindingEvent e) {
System.out.println("A value has been bound to the session: " + userName);
}
public void valueUnbound(HttpSessionBindingEvent e) {
System.out.println("Goodbye " + userName);
}
}