Select query using Prepared Statement

[Deva Devaa]

I do not know what is wrong in my code. Following are the conditions in my code given below:

I will enter the customer id in the jTextField
After Entering the customer id then in the Database it will search relative information of that customer id (customer_id,customer_name,customer_contact).
After Collecting relative information of that particular customer id, it will display on the jTextField.
These is my code given below:

import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.*;

public abstract class customer_details extends JFrame implements ActionListener
{
    JTextField textFieldId;
    JTextField textFieldId1;
    JTextField textFieldId2;
    JTextField textFieldId3;    
    JLabel l1;
    JLabel l2;
    JLabel l3;
    JLabel l4;
    JLabel l5;
    JButton b1,b2;
    Container c = getContentPane();
    customer_details()
    {
        super("Shree Datta Digambar");
        setBounds(140,250,777,555);
        c.setLayout(null);
        textFieldId = new JTextField();        
        textFieldId1 = new JTextField();
        textFieldId2 = new JTextField();
        textFieldId3 = new JTextField();
        this.setExtendedState(JFrame.MAXIMIZED_BOTH);
        l1 = new JLabel("Update Customer Details:-");
        l2 = new JLabel("Customer Id");
        l3 = new JLabel("Customer Id");
        l4 = new JLabel("Name");
        l5 = new JLabel("Contact");
        l1.setBounds(10,10,340,20);
        l2.setBounds(10,20,140,70);
        l3.setBounds(10,100,140,70);
        l4.setBounds(100,100,140,70);
        l5.setBounds(270,100,140,70);
        textFieldId.setBounds(10,70,70,20);         
        textFieldId1.setBounds(10,160,70,20); 
        textFieldId2.setBounds(100,160,150,20); 
        textFieldId3.setBounds(270,160,90,20); 
        b1 = new JButton("Ok");
        b1.setBounds(100,70,50,20);   
        b2 = new JButton("Update");
        b2.setBounds(380,160,90,20);  
        c.add(b1);
        c.add(b2);
        c.add(l1);
        c.add(l2);
        c.add(l3);
        c.add(l4);
        c.add(l5);
        c.add(textFieldId);
        c.add(textFieldId1);
        c.add(textFieldId2);
        c.add(textFieldId3);       
        setVisible(true);
        setDefaultCloseOperation(EXIT_ON_CLOSE);                
        b1.addActionListener(this);               
        b2.addActionListener(this);
    }
    public static void main(String[] args) 
    {
        customer_details eeap=new customer_details() {};
    }
    public void actionPerformed(ActionEvent e)
    {               
        System.out.println("You clicked the button");             
        if(e.getSource()==b1)
        {
            try 
            {
                Connection con;
                ResultSet rs1 = null;
                Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
                con = DriverManager.getConnection("jdbc:odbc:Dalvi");
                                        
                    java.sql.Statement st = con.createStatement();
                    PreparedStatement ps = con.prepareStatement
                    ("SELECT customer_id,customer_name,customer_contact FROM customer_details WHERE customer_id = ?");                          
                    ps.setString(1,textFieldId.getText());
                    ps.executeQuery();
                    while(rs1.next())
                    {                     
                            textFieldId1.setText(rs1.getString("customer_id"));
                            textFieldId2.setText(rs1.getString("customer_name"));
                            textFieldId3.setText(rs1.getString("customer_contact"));                       
                    }               
                    textFieldId.setText("");
                    customer_details.this.dispose(); 
                    MainMenu mm = new MainMenu() {};
            } 
            catch (ClassNotFoundException ex) {
                Logger.getLogger(customer_details.class.getName()).log(Level.SEVERE, null, ex);
            }
                catch (SQLException s) 
                        {
                            System.out.println("SQL code does not execute.");
                            JOptionPane.showMessageDialog(null,"Please Enter the Detail Correctly");
                        }
        } 
    }
}

[Ulf Dittmer]

What, exactly, does the code do now, and how is that different from what you were expecting it to do? At which point does the code's behavior start to deviate from your expectation?

Is the actionPerformed method ever being called? Is the "try" block in line 75 ever being executed? Also, you should print out the full stack trace in the catch handler in line 102. Currently the code discards all information that would help you debug this issue.

[Deva Devaa]

I am getting error in line no 86

while(rs1.next())
                {                   
                    textFieldId1.setText(rs1.getString("customer_id"));
                    textFieldId2.setText(rs1.getString("customer_name"));
                    textFieldId3.setText(rs1.getString("customer_contact"));   
                }  

[Ulf Dittmer]

... but you won't tell us what the error is? Post the full stack trace.

[Deva Devaa]

error



You clicked the button
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at customer_details.actionPerformed(customer_details.java:85)

[Ulf Dittmer]

So which object is null? My guess is it's "rs1", because the code you posted never assigns something other than "null" to it.

[Deva Devaa]

I corrected My Code as:

 ResultSet rs1=ps.executeQuery();

Now Query is run successfully but the result it not show in the jtextfield

[Ulf Dittmer]

Have you checked that all the records that you think should be returned by the query are in fact being returned by the query?