membercontroller.java

图书馆检索系统

import java.io.IOException;
import java.net.URLEncoder;
import java.sql.SQLException;
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 library.Book;
import library.Hold;
import library.Member;

public class MemberController extends Controller {
  public void doPost (HttpServletRequest req,
          HttpServletResponse res) throws ServletException, IOException {
    String action = req.getParameter("action");

    // Output for debug purposes.
    System.err.println("MemberController: " + action);

    // Take the appropriate action.
    if (action.equals("placehold")) {
      placeHold(req, res);
    } else if (action.equals("makefav")) {
      makeFav(req, res);
    } else if (action.equals("login")) {
      login(req, res);
    } else if (action.equals("viewborrowed")) {
      viewBorrowed(req, res);
    } else if (action.equals("viewonhold")) {
      viewOnHold(req, res);
    } else {
      res.sendRedirect("/library/index.jsp");
    }
  }

  private void viewBorrowed (HttpServletRequest req, HttpServletResponse res)
          throws ServletException, IOException {
    // Get the session object.
    HttpSession session = req.getSession();

    // Retrieve the member.
    Member member = (Member) session.getAttribute("member");

    // Get the checked out books.
    Book book = null;

    try {
      book = member.getCheckedOutBooks();
    } catch (SQLException se) {
      System.err.println(se.toString());
      sendErrorRedirect(req, res, se);
      return;
    }

    // Store the book object in the session.
    session.setAttribute("book", book);

    // Redirect to the display page.
    res.sendRedirect("/library/viewborrowedbooks.jsp");
  }

  private void viewOnHold (HttpServletRequest req,
          HttpServletResponse res) throws ServletException, IOException {
    // Get the session object.
    HttpSession session = req.getSession();

    // Retrieve the member.
    Member member = (Member) session.getAttribute("member");

    // Get the held books.
    Hold hold = null;

    try {
      hold = member.getHolds();
    } catch (SQLException se) {
      System.err.println(se.toString());
      sendErrorRedirect(req, res, se);
      return;
    }

    // Store the book object in the session.
    session.setAttribute("hold", hold);

    // Redirect to the display page.
    res.sendRedirect("/library/viewheldbooks.jsp");
  }

  private void login(HttpServletRequest req,
          HttpServletResponse res) throws ServletException, IOException {
    // Get the session object.
    HttpSession session = req.getSession();

    Member member = (Member) session.getAttribute("mem");

    // The passwd and ssn parameters will be present when attempting
    // to login.
    String pass = req.getParameter("passwd");
    int ssn = (req.getParameter("ssn").equals("")) ? 0 :
            Integer.parseInt(req.getParameter("ssn"));

    // A callNumber parameter may or may not be present,
    // One will be present if a member clicked "Place Hold"
    // without being logged in, and then attempts to log in.
    String hcn =
            (req.getParameter("hcn") == null) ? "" : req.getParameter("hcn");
    String fcn =
            (req.getParameter("fcn") == null) ? "" : req.getParameter("fcn");

    // When redirecting to another page, include a forwarded
    // call number to hold (if any).
    String hcnparam = hcn.equals("") ? "" : "?hcn=" + hcn;
    String fcnparam = fcn.equals("") ? "" : "?fcn=" + fcn;

    String cnparam = hcn.equals("") ? fcnparam : hcnparam;

    // Lets invalidate the session
    // to get rid of the unneeded Member session attribute.
    session.invalidate();
    session = req.getSession();

    try {
      if (member.validate(ssn, pass)) {
        session.setAttribute("member", member);

        res.sendRedirect("/library/memberaccount.jsp" + cnparam);
      } else {
        // The password was not validated.  We simply
        // set an error message, and redirect back to
        // the member login page.
     	Member m = new Member();

        session.setAttribute("mem", m);

        m.setErrors("generic","Invalid user id and/or password");
        res.sendRedirect(URLEncoder.encode("/library/member.jsp" + cnparam, "UTF-8"));
      }
    } catch (Exception e2) {
      // Something bad happened, so redirect to the
      // error page.
      System.err.println(e2.toString());
      sendErrorRedirect(req, res, e2);
    }
  }

  private void placeHold(HttpServletRequest req, HttpServletResponse res) 
          throws ServletException, IOException {
    // Get the session object.
    HttpSession session = req.getSession();

    Member member = (Member) session.getAttribute("member");

    // Now get the callnumber parameter.
    String cn = req.getParameter("cn");

    // Before placing a hold, we must first make sure that
    // a member is logged in.  If they are not logged in,
    // redirect to the member login page.
    if (member == null) {
      res.sendRedirect(URLEncoder.encode("/library/member.jsp?hcn=" + cn, "UTF-8"));
    } else {
      try {
        int ok = member.placeHold(cn) ? 1 : 0;

        res.sendRedirect(URLEncoder.encode("/library/hold_done.jsp?cn=" 
                + cn + "&ok=" + ok, "UTF-8"));
      } catch (Exception e) {
        System.err.println(e.toString());
        sendErrorRedirect(req, res, e);
      }
    }
  }

  private void makeFav(HttpServletRequest req, HttpServletResponse res) 
          throws ServletException, IOException {
    // Get the session object.
    HttpSession session = req.getSession();

    Member member = (Member) session.getAttribute("member");

    // Now get the callnumber parameter.
    String cn = req.getParameter("cn");

    // Before placing a hold, we must first make sure that
    // a member is logged in.  If they are not logged in,
    // redirect to the member login page.
    if (member == null) {
      res.sendRedirect(URLEncoder.encode("/library/member.jsp?fcn=" + cn, "UTF-8"));
    } else {
      try {
        int ok = member.addFav(cn) ? 1 : 0;

        res.sendRedirect(URLEncoder.encode("/library/addfav_done.jsp?cn=" 
                + cn + "&ok=" + ok, "UTF-8"));
      } catch (Exception e) {
        System.err.println(e.toString());
        sendErrorRedirect(req, res, e);
      }
    }
  }
}