librariancontroller.java

来自「图书馆检索系统」· Java 代码 · 共 145 行

import java.io.IOException;
import java.net.URLEncoder;
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.Librarian;
import library.Member;

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

    if (action.equals("checkin")) {
      checkin(req, res);
    } else if (action.equals("checkout")) {
      checkout(req, res);
    } else if (action.equals("login")) {
      login(req, res);
    } else {
      res.sendRedirect("/library/index.jsp");
    }
  }

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

    Librarian librarian = (Librarian) session.getAttribute("librarian");
    Book book = (Book) session.getAttribute("book");

    // Get the bookid parameter
    int bookID = (req.getParameter("bookID") == null) ? 0 : Integer.parseInt(req.getParameter("bookID"));

    // Set the book object to the specified book.
    if (book.getBook(bookID)) {
      try {
        // Check in.
        if (book.checkIn()) {
          res.sendRedirect("/library/entrycomplete.jsp?action=checkedin");
        } else {
          res.sendRedirect("/library/librarianaccess.jsp");
        }
      } catch (Exception e) {
        System.err.println("Checkin failed: " + e.toString());
        sendErrorRedirect(req, res, e);
      }
    } else {
      // This book did not exist.
      book.setErrors("checkinbook", "This book does not exist");
      res.sendRedirect("/library/librarianaccess.jsp");
    }
  }

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

    Librarian librarian = (Librarian) session.getAttribute("librarian");    
    Book book = (Book) session.getAttribute("book");

    // Get the bookid parameter
    int bookID = (req.getParameter("bookID") == null) ? -1 : Integer.parseInt(req.getParameter("bookID"));

    // Get the member's ssn.
    int ssn = (req.getParameter("ssn") == null) ? -1 : Integer.parseInt(req.getParameter("ssn"));

    String pssn = (ssn == -1) ? "" : "?ssn" + ssn;

    // Set the book object to the specified book.
    if (book.getBook(bookID)) {
      // Retrieve the member object.
      Member member = new Member();
      
      if (member.getMember(ssn)) {
        try {
          // Check out.
          if (book.checkOut(librarian, member)) {
            res.sendRedirect("/library/entrycomplete.jsp?action=checkedout");
          } else {
            res.sendRedirect("/library/librarianaccess.jsp" + pssn);
          }
        } catch (Exception e) {
          System.err.println("Checkout failed: " + e.toString());
          sendErrorRedirect(req, res, e);
        }
      } else {
        // This member did not exist.
        book.setErrors("checkoutmember", "This member does not exist");
        res.sendRedirect("/library/librarianaccess.jsp" + pssn);
      }
    } else {
      // This book did not exist.
      book.setErrors("checkoutbook", "This book does not exist");
      res.sendRedirect("/library/librarianaccess.jsp" + pssn);
    }
  }

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

    try {
      Librarian librarian = (Librarian) session.getAttribute("lib");

      if (librarian.validate(
              Integer.parseInt(req.getParameter("ssn")),
              req.getParameter("passwd"))) {
        // Lets invalidate the session
        // to get rid of the unnecessary objects.
        session.invalidate();
        session = req.getSession();

        session.setAttribute("librarian", librarian);

        // Redirect to the librarian page.
        res.sendRedirect("/library/librarianaccess.jsp");

        return;
      }
    } catch(NumberFormatException nfe) {
      //nothing here. allows pass through to post catch
      //code that is common to nfe and validate == false
    } catch (Exception e) {
      System.err.println(e.toString());
      sendErrorRedirect(req, res, e);
      return;
    }

    session.invalidate();

    res.sendRedirect("/library/librarian.jsp?errMsg=" +
            URLEncoder.encode("Invalid user id and/or password",
                    "UTF-8"));
  }
}