Member Avatar for chan6212

How to retrieve all tables from database dynamically using servlets and jsp...please help me

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  • 4 Replies
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  • 5 Hours Discussion Span
  • Latest Post Latest Post by stultuske

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Member Avatar for stultuske

two points:
you may be a bit more specific (about what it is you want and what it is you've tried so far)
you may also consider posting this question in the jsp forum.

Member Avatar for chan6212

JSP PROGRAM

<%@page language="java" %>
<%@page import="java.sql.*;" %>


<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<table>
<tr>
<td>table name</td>
<td>${display.tablename}</td>
</tr>
</table>
</body>
</html>

SERVLET PROGRAM

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

    /**
     * @see HttpServlet#HttpServlet()
     */
    public DisplayTable() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        response.setContentType("text/html");
        Connection conn;
        PreparedStatement ps;
        ResultSet rs;
        String tablename=request.getParameter("tname");
        try{

            Class.forName("org.postgresql.Driver");
            System.out.println("Connecting to selected database....");
            conn=DriverManager.getConnection("jdbc:postgresql://172.16.5.222:5432/TESTDB","infotech","infotech");
            System.out.println("Connected to database Successfully");

            String query="select * from ?";
            ps=conn.prepareStatement(query);

            ps.setString(1, tablename);


            rs=ps.executeQuery();
            while(rs.next())
            {
                Display display=new Display (rs);   

            display.setTablename(rs.getString("tablename"));


             request.setAttribute("display",display);
             RequestDispatcher view = request.getRequestDispatcher("display.jsp");
             view.forward(request, response);
            }
            rs.close();
            ps.close();
            conn.close();

            }catch(Exception e){

        }

    }
}

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */

JAVA CLASS

import java.sql.ResultSet;
import java.sql.SQLException;


public class Display {
    private String tablename;

    public String getTablename() {
        return tablename;
    }

    public void setTablename(String tablename) {
        this.tablename = tablename;
    }

   public Display(ResultSet resultset) throws SQLException
   {
       this.tablename=resultset.getString("tablename");
   }
}

HTML CODE

<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<form action="display" method="get">
Table name<input type="text">
<input type="submit" value="GetDetails">
</form>
</body>
</html>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<servlet>

<servlet-name>DisplayTable</servlet-name>
<servlet-class>DisplayTable</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>DisplayTable</servlet-name>
<url-pattern>/display</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
</web-app>

/////I am not getting output..please try to help me

Edited by chan6212
Member Avatar for chan6212

It is not retrieving any table..please help me

Member Avatar for stultuske

you write code like this:

catch(Exception e){
        }

no wonder you have no idea what's going wrong. if an exception is thrown, you merely hide it. print the stacktraces and check your logs.

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