how does a JSP access or mutate a session bean with EL? (MVC)

Question

Right now the controller servlet seems to handle dispatching correctly, so far as I can tell, in that it dispatches to a specified JSP. It uses an instance of MyToken, kept in the session, to track the session. The controller dispatches to different JSP's depending on booleans of the MyToken instance.

I've put all the JSP's in WEB-INF so that only the controller servlet is exposed -- preferably, all requests/responses go through the servlet.

The intention is to use the MyToken object as a session bean.

How does a JSP access such a session bean with EL? The login.jsp page needs set the name value for the bean, and then dispatch back to the controller.

Can that be done with EL? Or, is it only possible to access a session bean with the JSTL?

It's intended as MVC, sans a framework -- just a very simple login with a simple bean for storing simple user data. A properties file contains a list of valid users which the token credentials are checked against.

Controller servlet:

package net.bounceme.dur.servlets;

import filter.PropertiesReader;
import java.io.IOException;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Map;
import java.util.Properties;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

@WebServlet("/controller")
public class Controller extends HttpServlet {

    private static final Logger log = Logger.getLogger(Controller.class.getName());

    protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        log.info("controller processing request..");
        String jsp = dispatcherLogic(request.getSession());
        request.getRequestDispatcher("/WEB-INF/" + jsp).forward(request, response);
    }

    private String dispatcherLogic(HttpSession session) {
        Properties properties = PropertiesReader.getProps();
        MyToken token = (MyToken) session.getAttribute("token");
        if (token != null) {
            token.setAuthenticated(properties.containsValue(token.getName()));
        } else {
            token = new MyToken();
        }
        log.info(token.toString());
        session.setAttribute("token", token);
        if (token.isAuthenticated()) {
            return "success.jsp";
        } else {
            if (token.isAttemptedLogin()) {
                return "fail.jsp";
            } else {
                return "login.jsp";
            }
        }
    }

    private String dispatcherLogic0(HttpSession session) {
        Map p = PropertiesReader.getPropsAsMap();
        Enumeration names = session.getAttributeNames();
        for (String s : Collections.list(names)) {
            log.info(s);
        }
        MyToken t = (MyToken) session.getAttribute("token");
        for (String s : p.keySet()) {
            //  t.getName() = p.containsValue(s);
        }
        return "hello.jsp";  //always to hello page for now
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    @Override
    public String getServletInfo() {
        return "controller";
    }
}


<%@page contentType="text/html" pageEncoding="UTF-8"%>


    
        
        login
    
    
        
            name

web.xml:



    
        AuthenticateFilter
        filter.AuthenticateFilter
        
            Name
            Value
        
    
    
        AuthenticateFilter
        /foo.jsp
    
    
        
            30
        
    
    
        index.html
    
    
        
            all
            all
            /*
            true

token for login credentials:

package net.bounceme.dur.servlets;

import java.util.logging.Logger;

public class MyToken {//should probably be immutable...

    private static Logger log = Logger.getLogger(MyToken.class.getName());

    private String name = "nemo";
    private String role = "captain";
    private String password = "abc";
    private boolean authenticated = false;  //remove down the road?
    private boolean attemptedLogin = false;  //remove down the road?

    public MyToken() {
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getRole() {
        return role;
    }

    public void setRole(String role) {
        this.role = role;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public boolean isAuthenticated() {
        return authenticated;
    }

    public void setAuthenticated(boolean authenticated) {
        this.authenticated = authenticated;
    }

    public boolean isAttemptedLogin() {
        return attemptedLogin;
    }

    public void setAttemptedLogin(boolean attemptedLogin) {
        this.attemptedLogin = attemptedLogin;
    }

    @Override
    public String toString() {
        return name + authenticated + attemptedLogin;
    }
}

how does a JSP access or mutate a session bean with EL? (MVC)

Answers (1)

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