Problema COM JSP + Servlet [RESOLVIDO]

Programação Java
#1

Bom pessoal to aprendendo JSP e Servlet
to fazendo um exemplo pelo netbeans, porem quando eu clico no botao para enviar os dados ele me joga em uma pagina em branco tendo eu que atualizar ela para que apareça o valor que eu quero, o que fiz de errado ??
Como melhorar o codigo?

P/s to aprendendo sozinho

Servlet

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package com.ask.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author ninguem
 */
public class TestServlet extends HttpServlet {
   String texto="<strong> - ";
    /** 
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {

            out.print(this.texto);

        } finally { 
            out.close();
       }
    } 

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /** 
     * Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    } 

    /** 
     * Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);

        this.texto += request.getParameter("testa")+" -- </strong>";
        PrintWriter writer = response.getWriter();
        writer.print(this.texto);
        writer.close();

    }

    /** 
     * Returns a short description of the servlet.
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}

JSP

<%-- 
    Document   : index
    Created on : 23/08/2010, 14:31:24
    Author     : ninguem
--%>

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
        <meta
            content="text/html; charset=ISO-8859-1"
            http-equiv="content-type">
        <title></title>
    </head>
    <body>
        <table
            style="width: 153px; height: 256px; text-align: left; margin-left: auto; margin-right: auto;"
            border="0" cellpadding="0" cellspacing="0">
            <tbody>
                <tr>
                    <td

                        style="text-align: center; vertical-align: top;">
                            <form action="TestServlet" method="POST">
                            <input type="text" name="testa" size="3">
                            <input type="submit" name ="TESTA">
                            <input type="reset" value="RESETA">
                        </form>
                    </td>
                </tr>
            </tbody>
        </table>
        <br>
    </body>
</html>
#2

Geralmente quando aparece alguma página em branco pode ser sinal de exception. Tente tratar as exceções e redirecionar para uma página de erro.

Se quiser pegue a apostila fj21 da caelum que fala de java para web

#3

Cara, coloca esse código:


         this.texto += request.getParameter("testa")+" -- </strong>";  
         PrintWriter writer = response.getWriter();  
         writer.print(this.texto);  
         writer.close();

aqui dentro :

    protected  void processRequest(HttpServletRequest request, HttpServletResponse response)  
     throws ServletException, IOException {  
         response.setContentType("text/html;charset=UTF-8");  
         PrintWriter out = response.getWriter();  
         try {  
             out.println(this.texto);
             this.texto += request.getParameter("testa")+"--</strong>";
             out.print(this.texto);

         } finally {   
             out.close();  
        }  
     }
#4

Opa vlw as dicas ae

seguinte colega meu achou o problema

tirei essa parte que o netbeans gera sozinho e funcionou, ta atualizando certinho.

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

rafael baixei a apostila e esta sendo muito boa obrigado pela dica =D

Abraços

#5

Edita aí então como [RESOLVIDO], :wink:

#6

Pronto =D

#7