将Servlet中提交的表单值传递给Java类，从而插入数据库

Question

The form values are submitted to the servlet and I need to retrieve those values into a class "RegisterDetails" and hence insert into the database "userdetails".. I used session to store the values and later retrieve it in the class file. Its a failure. How am I supposed to bring those values into the class file??? Later I need to pass the values into a jsp as well. Please instruct me. If there's any mistakes please help me...

Servlet: p1.java

import java.io.IOException;
import java.sql.Connection;

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

//import reg.common.Co;
//import agge.db.geg;
//import agge.model.m_login;
import reg.db.RegisterDetails;


/**
 * Servlet implementation class p1
 */
@WebServlet("/p1")
public class p1 extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public p1() {
        super();
        // TODO Auto-generated constructor stub
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    }
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        HttpSession session = request.getSession();
        String a=request.getParameter("username1");
        String b=request.getParameter("password1");
        String c = request.getParameter("confirmpassword1");
        String d = request.getParameter("email1");
        String ee = request.getParameter("mob1");
        String f =request.getParameter("address1");

        System.out.println("Hai User "+a);
        System.out.println("Password is "+b);


        session.setAttribute("de", a); 
        session.setAttribute("de1", b);
        session.setAttribute("de2", c);
        session.setAttribute("de3", d);
        session.setAttribute("de4", ee);
        session.setAttribute("de5",f);
        RegisterDetails details = new  RegisterDetails();

        session.setAttribute("details", details);
        getServletContext().getRequestDispatcher("/jsp/Welcome.jsp").forward(request, response);
    }
}

Class: RegisterDetails.java

package reg.db;

import javax.servlet.ServletRequest;
import javax.servlet.http.HttpSession;

import java.sql.*;
public class RegisterDetails {
    String user13;
    String pass13;
    String confpassword13;
    String email13;
    String mobile13;
    String address13;
    private ServletRequest session;


    String n=(String)session.getAttribute("de");
    String n1=(String)session.getAttribute("de1");
    String n2=(String)session.getAttribute("de2");
    String n3=(String)session.getAttribute("de3");
    String n4=(String)session.getAttribute("de4");
    String n5=(String)session.getAttribute("de5");



    public boolean insertDB() throws Exception {        

        Connection conn=null;
        PreparedStatement st = null;

        st=conn.prepareStatement("insert into user_details(username, password, confpassword, email,mobile, address) values ('" + n + "','" + n1 + "','" + n2 + "','" + n3 + "','" + n4 + "',' "+n5+ "')");

        ResultSet rs =st.executeQuery();
        boolean l_status=false;
        while(rs.next()){
            user13          =   rs.getString("username");
            pass13          =   rs.getString("password");
            confpassword13  =   rs.getString("confpassword");
            email13         =   rs.getString("email");
            mobile13            =   rs.getString("mobile");
            address13           =   rs.getString("address");
        }
        return l_status=true;

    }
}

Database connectivity: Dbconnect.java

package reg.common;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class Dbconnect {

    Connection conn=null;

    public  Connection getConnection() { 
         try {
             String driverName = "org.postgresql.Driver";
             Class.forName(driverName).newInstance(); 

             conn=DriverManager.getConnection("jdbc:postgresql://localhost:5432/postgres","postgres", "postgres");
         } 
         catch (ClassNotFoundException e) {e.printStackTrace();
             System.out.println("db Error1");
         } 
         catch (SQLException e) {
             e.printStackTrace();
             System.out.println("DB Error 2");
         }
         catch (Exception e) {

        }
         return conn;
    }

    public void closeConnection(Connection connection) {
        try{
            connection.close();
        }
        catch (Exception e) {

        }

    }
}

jsp:Welcome.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
    <%@ page import="reg.db.RegisterDetails" %>

<!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>

  Hai
<% RegisterDetails details = (RegisterDetails)session.getAttribute("details");%>

</body>
</html>

Answer 1

In your p1 servlet, you are setting your session attribute "details" with a new instance of RegisterDetails without setting any properties of that object (ie username, etc.).

Instead, you are setting those properties as cryptically named session attributes ("de", "de1" and so on).

This is likely to cause your issue (aside from all considerations in terms of architecture or security), since the RegisterDetails you retrieve will essentially be an empty object.

Answer 2

Try these few steps ... 1. Instead of storing the parameter values in various String objects, you should set the value of the data members of your RegisterDetails object

2. Create another class that specifically handles the job of working with the database (use the connection object in that class)

3. Create methods for CRUD operations in the above class and pass the RegisterDetails object.

4. Call the insert method of the newly created class from within your servlet and pass the RegisterDetails object in it

5. Once inserted then add the RegisterDetails object to the servlet request and dispatch the request to your jsp

Answer 3

You are setting the parameters received in your servlet into other session attributes and setting an empty RegisterDetails Object. Instead set the values received in the RegisterDetails object in you servlet. Something like this:-

RegisterDetails details = new  RegisterDetails();
details.user13=request.getParameter("username1");
details.pass13=request.getParameter("password1");
details.confpassword13= request.getParameter("confirmpassword1");
details.email13= request.getParameter("email1");
details.mobile13 = request.getParameter("mob1");
details.address13 =request.getParameter("address1");

This should solve your issue, but apart from this I suggest to redesign your solution and follow coding best practices. Alteast generate getter/setter methods for you RegisterDetails class, and then set the object data memeber values using that, intead of directly accessing them.

Edit:- It seems that the access specifier of your data members for RegisterDetails is default , change it to public to access and assign them values, since your servlet and RegisterDetails classes are in different packages. Although the recommended approach would be to set them as private and generate public getter/setters.