📄 bookdetailsservlet.java

📁 卡内基梅隆大学软件工程课件,很全面
💻 JAVA
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/* * * Copyright 2001 Sun Microsystems, Inc. All Rights Reserved. *  * This software is the proprietary information of Sun Microsystems, Inc.   * Use is subject to license terms. *  */import java.io.*;import java.util.*;import javax.servlet.*;import javax.servlet.http.*;import database.*;import cart.*;import util.Currency;import exception.*;/** * This is a simple example of an HTTP Servlet.  It responds to the GET * method of the HTTP protocol.  */public class BookDetailsServlet extends HttpServlet {   private BookDB bookDB;   public void init() throws ServletException {      bookDB =            (BookDB)getServletContext().getAttribute("bookDB");         if (bookDB == null)             throw new UnavailableException("Couldn't get database.");   }   public void destroy() {         bookDB = null;   }         public void doGet (HttpServletRequest request,                       HttpServletResponse response)        throws ServletException, IOException {        HttpSession session = request.getSession(true);    		ResourceBundle messages = (ResourceBundle)session.getAttribute("messages");   // set headers and buffer size before accessing the Writer        response.setContentType("text/html");            response.setBufferSize(8192);            PrintWriter out = response.getWriter();   // then write the response        out.println("<html>" +                    "<head><title>" + messages.getString("TitleBookDescription") + "</title></head>");        // Get the dispatcher; it gets the banner to the user        RequestDispatcher dispatcher =               getServletContext().getRequestDispatcher("/banner");                                                   if (dispatcher != null)               dispatcher.include(request, response);                       //Get the identifier of the book to display        String bookId = request.getParameter("bookId");        if (bookId != null) {            // and the information about the book            try {               BookDetails bd = bookDB.getBookDetails(bookId);               Currency c = (Currency)session.getAttribute("currency");               if (c == null) {                  c = new Currency();                  c.setLocale(request.getLocale());                  session.setAttribute("currency", c);               }               c.setAmount(bd.getPrice());                     //Print out the information obtained               out.println("<h2>" + bd.getTitle() + "</h2>" +                           "&nbsp;" + messages.getString("By") + " <em>" + bd.getFirstName() + " " +                           bd.getSurname() + "</em> &nbsp; &nbsp; " +                           "(" + bd.getYear() + ")<br> &nbsp; <br>" +                           "<h4>" + messages.getString("Critics")+ "</h4>" +                           "<blockquote>" + bd.getDescription() +                           "</blockquote>" +                           "<h4>" + messages.getString("Price") + c.getFormat() + "</h4>" +                           "<p><strong><a href=\"" +                           response.encodeURL(request.getContextPath() + "/catalog?bookId=" + bookId) +                           "\">" + messages.getString("CartAdd") + "</a>&nbsp;&nbsp;&nbsp;" +                           "<a href=\"" +                            response.encodeURL(request.getContextPath() + "/catalog") + "\">" + messages.getString("ContinueShopping") + "</a></p></strong>");            } catch (BookNotFoundException ex) {                     response.resetBuffer();                     throw new ServletException(ex);            }                                            }        out.println("</body></html>");        out.close();    }    public String getServletInfo() {        return "The BookDetail servlet returns information about" +               "any book that is available from the bookstore.";    }}
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