jsp文件的404状态glassfish错误

Question

我一直在尝试使用jsp和servlets NetBeans发送邮件。我尝试了很多代码，但运行项目时出现了常见的404状态错误。我使用glassfish服务器3.以下是我的代码。

的index.jsp：

<form action="sendmail">

          Sending Id :<input type="text" name="semail" />
           Title:<input type="text" name="title" />
           Message :</td><td><textarea rows="5" cols="30" name="msg"></textarea>
           <input type="submit" name="submit" value="mail" />
        </table>
    </form>

sendmail.java：

    import java.io.IOException;
    import java.io.PrintWriter;
    import java.util.Date;
    import java.util.Properties;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.mail.*;
    import javax.mail.internet.*;

    public class sendmail extends HttpServlet
    {

    String username ="//some username";
    String password = "//some password";
    String smtphost = "smtp.gmail.com";
    String compression = "";
    String from = "abc@gmail.com";
    String to = "";
    String body = "";
    Transport tr = null;

    protected void processRequest(HttpServletRequest request, HttpServletResponse        response) throws ServletException, IOException
    {
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();
    try {

        String semail = request.getParameter("semail");
        String title = request.getParameter("title");
        String msg2 = request.getParameter("msg");

        to=semail;
        compression=title;
        body=msg2;

        Properties props = System.getProperties();
     props.put("mail.smtp.auth", "true");

     // Get a Session object
     Session mailSession = Session.getDefaultInstance(props, null);

     // construct the message
     Message msg = new MimeMessage(mailSession);

     //Set message attributes
     msg.setFrom(new InternetAddress(from));
     InternetAddress[] address = {new InternetAddress(to)};
     msg.setRecipients(Message.RecipientType.TO, address);
     msg.setSubject(compression);
     msg.setText(body);
     msg.setSentDate(new Date());

     tr = mailSession.getTransport("smtp");
     tr.connect(smtphost, username, password);
     msg.saveChanges();
     tr.sendMessage(msg, msg.getAllRecipients());
     tr.close();
     out.print("<script>alert('Mail has been sent successfully......');</script>");
     response.sendRedirect("success.jsp");
     }
    catch (Exception e)
    {
        response.sendRedirect("fail.jsp");

    } finally {
        out.close();
    }
}

}

success.jsp和fail.jsp将分别显示单词success和failed。

请帮助解决错误！提前谢谢。