problem about servlet and class

[mehdi chorsi]

Hi i have a problem
i want to show data in jsp page
i created a servlet page for this and i created a java class for fetch data from data base

now i don't know how can get connection between Servlet and class to get list from class !!!

ShowClassTypesServlet.java

package com.ikco.krishnasql.action;

import com.ikco.krishnasql.dao.Declaration;
import com.ikco.krishnasql.dao.InsertDataDAO;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ShowClassTypesServlet extends HttpServlet {
   
  InsertDataDAO showDataDao =new InsertDataDAO();
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {
         
          showDataDao.showdata();
         
          RequestDispatcher dispatcher = request.getRequestDispatcher("/DisplayRecords.jsp");
            dispatcher.forward(request, response);
        } catch (Exception e){


        }

    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

   
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>
}

InsertDataDAO.java

package com.ikco.krishnasql.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

public class InsertDataDAO {

    Connection con;
    Statement st;
    ResultSet rs;
    List lst = new ArrayList();

    public void save(Declaration declira) throws SQLException {
        Connection con = getConnection();
        String insert = "INSERT INTO CLASS_TAYPES (NAME, MIN_STUDENTS, DESCRIPTION, MAX_STUDENTS) VALUES (?, ?, ?, ?)";
        PreparedStatement ps = con.prepareStatement(insert);
        ps.setString(1, declira.getName());
        ps.setString(2, declira.getMin_students());
        ps.setString(3, declira.getDescription());
        ps.setString(4, declira.getMax_students());
        ps.executeUpdate();
        ps.close();
        con.commit();
        System.out.println("Storing Student Object is Done!");
    }

    public void update(Declaration std) {
        Connection con = getConnection();
        String update = "UPDATE CLASS_TAYPES WHERE name ";
        System.out.println("Storing Student Object is Done!");
    }

    public void remove(Declaration std) {
        System.out.println("Storing Student Object is Done!");
    }

    public void showdata() throws SQLException {
        String show = "SELECT * FROM CLASS_TAYPES";
        Connection con = getConnection();
        Statement st = con.createStatement();
        st.executeQuery(show);
        rs = st.getResultSet();
        while (rs.next()) {
            lst.add(rs.getString("name"));
            lst.add(rs.getString("min_students"));
            lst.add(rs.getString("description"));
            lst.add(rs.getString("max_students"));
        }
        rs.close();



    }

    public List<Declaration> findAll() {
        System.out.println("Storing Student Object is Done!");
        return null;
    }

    public Connection getConnection() {
        try {
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/ocool2", "root", "9999");
            con.setAutoCommit(false);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return con;

    }

DisplayRecords.jsp

<%@page import="java.util.List"%>
<%@page import="java.util.Iterator"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <table align="center" border ="1px" with ="80%">
            <%Iterator itr;%>
            <%List data = (List) request.getAttribute("EmpData");
            for (itr = data.iterator(); itr.hasNext();){
           %>     
           <tr>
               <% String s = (String) itr.next();%>
               <td><%=s%></td>
               <td><%= itr.next() %></td>
               <td><%= itr.next() %></td>
               <td><%= itr.next() %></td>
               <td> <input type="submit" value="Edit" name="edit" onclick="editRecord(<%=s%>);"> </td>
               <td> <input type="submit" value="Delete" name="delete" onclick="deleteRecord(<%=s%>);"> </td>
           
           <%}%>
           </tr>
        </table>
    </body>
</html>

[Jeanne Boyarsky]

showData() builds a list which is good. It needs to return the list. Then the servlet can put the list in a request.setAttribute() call so it becomes available for the JSP.