loginservlet.java

考勤管理系统源码

package com.wiley.compBooks.EJwithUML.TimecardUI;

import javax.servlet.http.*;
import javax.servlet.*;

import javax.naming.*;
import javax.ejb.*;
import java.rmi.*;
import javax.rmi.PortableRemoteObject;

import java.io.*;

import com.wiley.compBooks.EJwithUML.Base.HtmlPrimitives.Core.*;
import com.wiley.compBooks.EJwithUML.Base.HtmlPrimitives.Layout.*;
import com.wiley.compBooks.EJwithUML.Base.HtmlPrimitives.ContentElements.*;
import com.wiley.compBooks.EJwithUML.Base.EjbUtil.*;
import com.wiley.compBooks.EJwithUML.Base.ApplicationExceptions.*;
import com.wiley.compBooks.EJwithUML.TimeCardWorkflow.*;
import com.wiley.compBooks.EJwithUML.TimecardProducers.*;


/**
 *
 * The LoginServlet class uses the TimecardWorkflow and
 * HtmlPrimitives packages to create the formatted HTML
 * for the Login form and to validate the user.
 *
 */
public class LoginServlet extends BasicTimecardServlet
{
  private LoginWorkflowHome lwfHome = null;

  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
  {
    doPost(request, response);
  }

  /** Overrides method from HttpServlet.
      doPost is called by the servlet engine. */
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
  {
    System.out.println("LoginServlet: doPost");
    PagePrimitive pagePrimitive = null;

    try
    {
      // extract user name and password
      String username = request.getParameter(TimecardKey.USERNAME.getKeyText());
      String password = request.getParameter(TimecardKey.PASSWORD.getKeyText());

      if (username == null)
      {
        pagePrimitive = buildLoginPage();
      }
      else
      {
        if (this.isLoginValid(username, password))
        {
          HttpSession session = request.getSession(true);
          session.setAttribute(TimecardKey.USERNAME.getKeyText(), username);

          pagePrimitive = buildWelcomePage(username);
        }
        else
        {
          pagePrimitive = buildLoginInvalidPage();
        }
      }
    }
    catch (NamingException e)
    {
      pagePrimitive = this.getErrorPage("Error During Login\n", e);
    }
    catch (CreateException e)
    {
      pagePrimitive = this.getErrorPage("Error During Login\n", e);
    }

    StringBuffer buffer = new StringBuffer();
    pagePrimitive.buildContent(buffer);
    response.getWriter().println(buffer);
    response.getWriter().flush();
    response.getWriter().close();
  }

  /** Build page for display on succesful login.*/
  PagePrimitive buildWelcomePage(String username)
  {
    PagePrimitive page = new TimecardPageProducer("Welcome");
    ParagraphPrimitive welcome = new ParagraphPrimitive(TimecardStyle.PAGE_TITLE, "Welcome, " +username);
    page.addToBody(welcome);
    LinkPrimitive link = new LinkPrimitive("/Timecard/RecordTimeServlet");
    link.addText("Enter Hours");
    page.addToBody(link);
    return page;
  }

  /** Build page for user input */
  PagePrimitive buildLoginPage()
  {
    SimpleInputFormProducer form = new SimpleInputFormProducer("Login", "Please enter your username and password.","Login", "./LoginServlet");
    form.addField("User Name", TimecardKey.USERNAME.getKeyText(), "");
    form.addMaskedField("Password", TimecardKey.PASSWORD.getKeyText(), "");

    PagePrimitive page = new TimecardPageProducer("Login");
    page.addToBody(form);
    return page;
  }

  /** Build page with error message when login fails. */
  PagePrimitive buildLoginInvalidPage()
  {
    PagePrimitive page = buildLoginPage();

    SpanPrimitive errorMessage = new SpanPrimitive(Style.WARNING_TEXT, "Invalid username or password. Remember, case matters.");
    page.addToBody(errorMessage);
    return page;
  }

  /** Answer true if the login data matches the database.*/
  private boolean isLoginValid(String username, String password) throws NamingException, RemoteException, CreateException
  {
    boolean valid = false;

    try
    {
      createLoginWorkflowHome();
      LoginWorkflow lwf = lwfHome.create();
      valid = lwf.isUserValid(username, password);
    }
    catch (DataNotFoundException e)
    {
      valid = false;
    }

    return valid;
  }

  private void createLoginWorkflowHome() throws NamingException
  {
    if (lwfHome == null)
    {
      Context initial = new InitialContext();
      Object objref = initial.lookup(EjbReferenceNames.LOGIN_WORKFLOW_HOME);
      lwfHome = (LoginWorkflowHome)PortableRemoteObject.narrow(objref,LoginWorkflowHome.class);
    }
  }
}