CODEWITHSUNDEEP
jspservlets
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Reputation: 21

display data in jsp from servlet

I am a begginer,I am trying to display data in database. I have a controller servlet, DBhelper, table.jsp and an index...

this is the controller servlet

import java.io.IOException;
import java.sql.ResultSet;

import javax.annotation.Resource;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;
import demo2.DBhelper;

/**
 * Servlet implementation class servletJsp
 */
@WebServlet("/servletJsp")
public class controller extends HttpServlet {
    private static final long serialVersionUID = 1L;

    @Resource(name="")
    private DataSource dataSource;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        String page;
        if(request.getParameterMap().containsKey("page")){
            page =request.getParameter("page");
        }else{
            page="index";
        }
        if(page.equals("table")){
            ResultSet rs =new DBhelper().getUsers(dataSource);
            request.getRequestDispatcher("table.jsp").forward(request, response);
            request.setAttribute("users", rs);
    }

}
}

this is the DBhelper..

package demo2;



import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;


import javax.sql.DataSource;

public class DBhelper {

    private ResultSet users =null;

    public ResultSet getUsers(DataSource dataSource) {

        Connection con;
        Statement st;

        try{
        con =dataSource.getConnection();
        st=con.createStatement();

        String query="select * from authorities";
        users= st.executeQuery(query);
        }catch(Exception e){

            e.printStackTrace();
        }
        return users;
    }
}

this is the table.jsp

<%@ page import="java.sql.ResultSet" %>
<%
ResultSet rs = (ResultSet)request.getAttribute("users");
while(rs.next()){
    String username = rs.getString("username");
    out.println(username);``
}

%>

I am getting an error in the table.jsp, in the line while(rs.next)

Upvotes: 0

Views: 2859

Answers (1)

Jozef Chocholacek
Jozef Chocholacek

Reputation: 2924

The problem is here:

if(page.equals("table")){
    ResultSet rs = new DBhelper().getUsers(dataSource);
    request.getRequestDispatcher("table.jsp").forward(request, response);
    request.setAttribute("users", rs);
}

You are forwarding the flow to the JSP page before setting the users attribute, thus your ResultSet rs is null in your JSP. Change the order to 

if(page.equals("table")){
    ResultSet rs = new DBhelper().getUsers(dataSource);
    request.setAttribute("users", rs);
    request.getRequestDispatcher("table.jsp").forward(request, response);
}

and it should work (of course, if DBhelper.getUsers(...) returns not null ResultSet).

Upvotes: 2

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