How to display data from database to JSP Page in Struts2

[akshat Singh]

I am new to Struts and want to display the Registration ID which is generating automatically by the mysql to my success page when user submits the form, please guide me how to achieve it...

My Action...

package net.Candidate.application.action; 

import java.io.*; 
import java.sql.*; 
import java.util.*; 

import javax.naming.*; 
import com.opensymphony.xwork2.ActionSupport; 
import com.opensymphony.xwork2.ActionContext; 

import net.database.*; 
import net.Candidate.application.model.Apply; 
import net.Candidate.application.model.Appform; 

public class SubmitAppFormAction extends ActionSupport { 
        
        private Appform appform; 
        private int onlineID = 0; 
        
        public String add() { 
                try 
                { 
                        Connection connect = null; 
                        ResultSet result = null; 
                        PreparedStatement pstmt = null; 
                        
                        DBConnection getConnect = new DBConnection(); 
                        connect = getConnect.getCon(); 
                        System.out.println("JDBC MySQL Connection...."); 
                                
                                String query = "INSERT INTO applicant VALUES(NULL,?,?,?,?,?,?.........NOW())"; 
                                pstmt = connect.prepareStatement(query); 
                                pstmt.setString(1, appform.getName()); 
                                pstmt.setString(2, appform.getSurname()); 
                                pstmt.setString(3, appform.getDOB()); 
                                pstmt.setString(4, appform.getGender()); 
                                pstmt.setString(5, appform.getNationality()); 
                                pstmt.setString(6, appform.getEmail());	
                                ........................ 
                                ........................	
                                pstmt.executeUpdate(); 
                                
                                int OnlineID = 0;
                                ResultSet result_ID = null; 
                        
                                String IDqry = "Select OnlineID from applicant where Email=?"; 
                                pstmt = connect.prepareStatement(IDqry); 
                                pstmt.setString(1, appform.getEmail()); 
                                result_ID = pstmt.executeQuery(); 
                                { 
                                        while (result_ID.next()) 
                                        { 
                                            OnlineID = result_ID.getInt(1);     
                                        } 
                                 } 
                                        
                                String Securityquery = "INSERT INTO security VALUES("+OnlineID+",?,?,?,?)"; 
                                pstmt = connect.prepareStatement(Securityquery); 
                                pstmt.setString(1, appform.getEmail()); 
                                pstmt.setString(2, appform.getReferee1Email()); 
                                pstmt.setString(3, appform.getReferee2Email()); 
                                pstmt.setString(4, appform.getPasswd()); 
                                pstmt.executeUpdate();	
                                
                                setOnlineID(this.onlineID); 
                                return "success";
                } 
                catch (SQLException e) { 
                        e.printStackTrace(); 
                } 
                return SUCCESS; 
        } 
        
        public int getOnlineID() { 
                return onlineID; 
        } 
        
        public void setOnlineID(int onlineID) { 
                //Implementation of the application specific logic to retrieve the data from the database// 
                        try 
                        { 
                        Connection connect = null; 
                        PreparedStatement pstmt = null; 
                        DBConnection getConnect = new DBConnection(); 
                        connect = getConnect.getCon(); 
                        
                        int OnlineID = 0; 
                        ResultSet result_OID = null; 
                        String OIDqry = "Select OnlineID from applicant where Email=?"; 
                                        pstmt = connect.prepareStatement(OIDqry); 
                        pstmt.setString(1, appform.getEmail()); 
                        result_OID = pstmt.executeQuery(); 
                        { 
                                while (result_OID.next()) 
                                { 
                                    OnlineID = result_OID.getInt(1); 
                                } 
                            } 
                        } 
                          
                 catch (SQLException e) { 
                        e.printStackTrace(); 
                 }	
                }
        
        public Appform getAppform() { 
                return appform; 
        }	
        public void setAppform(Appform appform) { 
                this.appform = appform; 
        } 
        
} 

I TRIED BY THE METHOD HIGHLIGHTED IN BOLD:

I want to display the OnlineID which is generated on my JSP page, but it is showing OnlineID as 0.

My JSP:

<%@ taglib prefix="s" uri="/struts-tags" %> 

<div id="heading">
<s:text name="title_applysuccess"/>
</div>

<div id="index">        
<s:text name="apply_Success"/>

<s:text name="apply_SuccessID"/><s:property value="%{onlineID}"></s:property>
</div>

Please help........

[Joe Ess]

New to Java? I see a couple of problems in your code. First, you declare an instance scope variable:

private int onlineID = 0; 

Then you pass it to a class method, which is totally unnecessary, because it is already accessible:

setOnlineID(this.onlineID);

Then you create a new, but very similarly named variable in the method (Bad Idea!):

int OnlineID = 0;  

and you set the value for the local variable, but you do not set the value for the instance variable:

OnlineID = result_OID.getInt(1);  

You also do not need to use OGNL syntax on your JSP tag (the percent sign and brackets). The JSP tag will take the property name itself as an argument:

<s:property value="%{onlineID}">

[Souvvik Basu]

hi..
Can anyone please direct me to some tutorial that teaches me how to use database in a struts2 application? Searching the net, I found information in bits and pieces, but nothing comprehensive which teaches the stuff (without assuming that the reader knows the basics of how to do it).
Thanks in advance for the help...