Hi Eric,,
If you need to see the full text of the exception then try this:
Change
e.printStackTrace();
to
e.printStackTrace(System.out);
or
e.printStackTrace(System.err);
I believe that the System.out will go to the console,
and System.err will be logged in the JWS error_log file
at <base_dir>\logs\javawebserver\webpageservice\error_log
Spencer
[EMAIL PROTECTED]
eric liu wrote:
>
> Sorry I post this question again. I am sure some of you tried the Bookstore
> example, you don't have any problem running it? Every
> time I tried to follow the tutorials to learn more, I was blocked by
> this question. Anybody can give an explanation? Thank you very
> much!
>
> Did you ever try the sample duke's bookstore provided by
> javasoft. The BookDetailServlet and CatalogServlet always output
> NullPointerException. I have worked on this for long time, right now my
> major problem is: debugging message does not show on the javawebserver
> console( when start the web server, leave it open, then message will show
> up, I used to debug in this way), so I can not check where cause the NPE. I
> use following code:
> >> String bookId = request.getParameter("bookId");
> >> try{
> >> bookId = request.getParameter("bookId");
> >> }catch(Exception e)
> >> {
> >> e.printStackTrace();
> >> System.out.println(e.getMessage());
> >> }
> >> System.out.println("bookId is: "+bookId);
> >>Nothing shows on the console.
>
> The full version of BookDetailServlet.java is
> >>here, gurus please help, the whole package is also attached for your
> convenience(oops, the package is too large to go through, but
> if you have javawebserver installed, it locates in the example/application
> directory)
> >>
> >>import java.io.*;
> >>import javax.servlet.*;
> >>import javax.servlet.http.*;
> >>import database.*;
> >>import cart.ShoppingCart;
> >>
> >>
> >>public class BookDetailServlet extends HttpServlet {
> >>
> >> public void doGet (HttpServletRequest request,
> >> HttpServletResponse response)
> >> throws ServletException, IOException
> >> {
> >> // Get the user's session and shopping cart
> >> HttpSession session = request.getSession(true);
> >> ShoppingCart cart =
> >> (ShoppingCart)session.getValue(session.getId());
> >>
> >> // If the user has no cart, create a new one
> >> if (cart == null) {
> >> cart = new ShoppingCart();
> >> session.putValue(session.getId(), cart);
> >> }
> >>
> >> // set content-type header before accessing the Writer
> >> response.setContentType("text/html");
> >> PrintWriter out = response.getWriter();
> >>
> >> // then write the response
> >> out.println("<html>" +
> >> "<head><title>Book Description</title></head>" +
> >>
> >> "<body bgcolor=\"#FFFFFF\">" +
> >> "<center>" +
> >> "<hr> <br> " +
> >> "<h1>" +
> >> "<font size=\"+3\" color=\"red\">Duke's </font>" +
> >> "<font size=\"+3\" color=\"purple\">Bookstore</font>"
> +
> >> "</h1>" +
> >> "</center>" +
> >> "<br> <hr> <br> ");
> >>
> >> //Get the identifier of the book to display
> >> String bookId = request.getParameter("bookId");
> >> if (bookId != null) {
> >>
> >> // and the information about the book
> >> BookDBServlet database = (BookDBServlet)
> >>
> >getServletConfig().getServletContext().getServlet("bookdb");
> >> BookDetails bd = database.getBookDetails(bookId);
> >>
> >> //Print out the information obtained
> >> out.println("<h2>" + bd.getTitle() + "</h2>" +
> >>
> >> " By <em>" + bd.getFirstName() + ", " +
> >> bd.getSurname() + "</em> " +
> >> "(" + bd.getYear() + ")<br> <br>" +
> >>
> >> "<h4>Here's what the critics say: </h4>" +
> >> "<blockquote>" + bd.getDescription() +
> >> "</blockquote>" +
> >>
> >> "<h4>Our price: $" + bd.getPrice() + "</h4>" +
> >>
> >> "<center>" +
> >> "<p><a href=\"" +
> >> response.encodeUrl("/servlet/catalog?Buy=" +
> >bookId)
> >>+
> >> "\"> Add this item to your shopping cart.</a></p>"
> >+
> >> "</center>");
> >> }
> >> 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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> >of the message "signoff SERVLET-INTEREST".
> >
> >Archives: http://archives.java.sun.com/archives/servlet-interest.html
> >Resources: http://java.sun.com/products/servlet/external-resources.html
> >LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
>
> ___________________________________________________________________________
> To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
> of the message "signoff SERVLET-INTEREST".
>
> Archives: http://archives.java.sun.com/archives/servlet-interest.html
> Resources: http://java.sun.com/products/servlet/external-resources.html
> LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
___________________________________________________________________________
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff SERVLET-INTEREST".
Archives: http://archives.java.sun.com/archives/servlet-interest.html
Resources: http://java.sun.com/products/servlet/external-resources.html
LISTSERV Help: http://www.lsoft.com/manuals/user/user.html
