HTTPステータス404 - 見つからない - サーブレットとJSP

Question

私は1つのWebアプリケーションで作業しています。 servletをテストしたいときに問題があります。 サーブレットのエラーが表示されたら -

HTTPステータス404 - 見つかりません。

私は別の同様の問題を検索しますが、解決策が見つかりません。私はサーブレットとjspファイルの間に接続がないと思います。私のコード下：

GetServletController

/* 
* To change this license header, choose License Headers in Project Properties. 
* To change this template file, choose Tools | Templates 
* and open the template in the editor. 
*/ 
package Servlets; 

import java.io.IOException; 
import java.io.PrintWriter; 
import java.util.Enumeration; 
import java.util.List; 
import javax.servlet.RequestDispatcher; 
import javax.servlet.ServletConfig; 
import javax.servlet.ServletContext; 
import javax.servlet.ServletException; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 

/** 
* 
* @author Adam 
*/ 
public class GetServletController extends HttpServlet { 

// private HandsDBUtil handsDBUtil; 
// 
// private ServletConfig config = getServletConfig(); 
// private ServletContext context = config.getServletContext(); 
// 
// private String user = null; 
// private String pass = null; 
// private String c_name = null; 
// private String url = null; 
// @Override 
// public void init() throws ServletException { 
//  super.init(); 
//  Enumeration enumeration = context.getInitParameterNames(); 
//  while (enumeration.hasMoreElements()) { 
//   String name = (String) enumeration.nextElement(); 
//   switch (name) { 
//    case "url": 
//     url = context.getInitParameter(name); 
//     break; 
//    case "pass": 
//     pass = context.getInitParameter(name); 
//     break; 
//    case "user": 
//     user = context.getInitParameter(name); 
//     break; 
//    case "c_name": 
//     c_name = context.getInitParameter(name); 
//     break; 
//   } 
//  } 
// 
//  handsDBUtil = new HandsDBUtil(user, pass, c_name, url); 
// 
// } 
    /** 
    * 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/plain; charset=ISO-8859-2"); 

     PrintWriter out = response.getWriter(); 

     out.println("WOW"); 

     HandsDBUtil handsDBUtil; 

     ServletConfig config = getServletConfig(); 
     ServletContext context = config.getServletContext(); 

     String user = null; 
     String pass = null; 
     String c_name = null; 
     String url = null; 

     Enumeration enumeration = context.getInitParameterNames(); 
     while (enumeration.hasMoreElements()) { 
      String name = (String) enumeration.nextElement(); 
      switch (name) { 
       case "url": 
        url = context.getInitParameter(name); 
        break; 
       case "pass": 
        pass = context.getInitParameter(name); 
        break; 
       case "user": 
        user = context.getInitParameter(name); 
        break; 
       case "c_name": 
        c_name = context.getInitParameter(name); 
        break; 
      } 
     } 

     handsDBUtil = new HandsDBUtil(user, pass, c_name, url); 

     out.println("wow"); 
     out.println(user); 
     try { 
      //listHands(request, response); 
      List<Hand> hands = handsDBUtil.getHands(); 
      System.out.println(hands); 
      request.setAttribute("HAND_LIST", hands); 

      RequestDispatcher dispatcher = request.getRequestDispatcher("getHands"); 
      dispatcher.forward(request, response); 
     } catch (Exception ex) { 
      throw new ServletException(ex); 
     } 
    } 

// private void listHands(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException, Exception { 
// 
//  List<Hand> hands = handsDBUtil.getHands(); 
// 
//  request.setAttribute("HAND_LIST", hands); 
// 
//  RequestDispatcher dispatcher = request.getRequestDispatcher("getHands"); 
//  dispatcher.forward(request, response); 
// 
// } 
    // <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); 
    } 

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

} 

JSP

<%@page import="java.util.*, Servlets.GetServletController, Servlets.Hand" %> 
<!DOCTYPE html> 
<html> 
    <head> 
     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 
     <title>Poker Hands List</title> 
    </head> 

    <form action="GetServletController"/> 

    <% 


     List<Hand> theHands = (List<Hand>) request.getAttribute("HAND_LIST"); 
     %> 

    <body> 

     <%= theHands %> 

     <div id="wrapper"> 
      <div id="header"> 
       <h2> 
        Poker Hands List 
       </h2> 
      </div> 
     </div> 

     <div id="container"> 
      <div id="content"> 

      </div> 
     </div> 
    </body> 
</html> 

web.xmlの

<?xml version="1.0" encoding="UTF-8"?> 
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> 
    <context-param> 
     <param-name>url</param-name> 
     <param-value>jdbc:derby://localhost:1527/lab</param-value> 
    </context-param> 
    <context-param> 
     <param-name>c_name</param-name> 
     <param-value>org.apache.derby.jdbc.ClientDriver</param-value> 
    </context-param> 
    <context-param> 
     <param-name>user</param-name> 
     <param-value>lab</param-value> 
    </context-param> 
    <context-param> 
     <param-name>pass</param-name> 
     <param-value>lab</param-value> 
    </context-param> 
    <servlet> 
     <servlet-name>ServletTest</servlet-name> 
     <servlet-class>Servlets.ServletTest</servlet-class> 
    </servlet> 
    <servlet> 
     <servlet-name>GetServletController</servlet-name> 
     <servlet-class>Servlets.GetServletController</servlet-class> 
    </servlet> 
    <servlet-mapping> 
     <servlet-name>ServletTest</servlet-name> 
     <url-pattern>/ServletTest</url-pattern> 
    </servlet-mapping> 
    <servlet-mapping> 
     <servlet-name>GetServletController</servlet-name> 
     <url-pattern>/GetServletController</url-pattern> 
    </servlet-mapping> 
    <session-config> 
     <session-timeout> 
      30 
     </session-timeout> 
    </session-config> 
    <welcome-file-list> 
     <welcome-file>getHands.jsp</welcome-file> 
     <welcome-file>index.jsp</welcome-file> 
     <welcome-file>mainMenu.jsp</welcome-file> 
    </welcome-file-list> 
</web-app> 

Answer 1

サーバー上のHTML, Image, JSP, Servletなど、任意のリソースへの要求のディスパッチへの使用にが使用されています。あなたはJSPにリクエストを転送したい場合は、あなたの場合は

RequestDispatcher dispatcher = request.getRequestDispatcher("getHands.jsp"); 

の下にあなたがサーブレットにリクエストを転送しているように定義する必要があります。

RequestDispatcher dispatcher = request.getRequestDispatcher("getHands"); 

なぜあなたは404エラー