Exception in thread
Hi everybody,
I am getting "Exception in thread "main" java.lang.NullPointerException" when I try to run the code. The pointed lines for the error are all related to searchDB method. Please, anyone can help figuring out what's wrong?
package onlineshopping;
import javax.swing.*; //for frame class
import java.awt.event.*; //for GUI event Handlers
import java.awt.*; //for container class
import java.sql.*;
public class OnlineShopping extends JFrame
{
// Data Members
private Connection OnlineShopping;
public Statement onlineStmt;
public ResultSet onlineRs;
// Constructors
public OnlineShopping(String title) {
super(title);
loadDriver();
connectDatabase();
int test[] = new int[100];
test = searchDB("clothes","Condition","used");
//JOptionPane.showMessageDialog(null,test[0]);
//JOptionPane.showMessageDialog(null,test[1]);
//JOptionPane.showMessageDialog(null,test[2]);
//JOptionPane.showMessageDialog(null,test[3]);
//writeToDB("clothes","Title","ok3");
//writeToDB("clothes","Quantity",7);
//addWindowListener(new WindowHandler());
}
//methods
private void loadDriver()
{
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
}
catch (ClassNotFoundException err)
{
JOptionPane.showMessageDialog(null,"Could not Load Sun Driver");
System.exit(1);
}
}
private void connectDatabase()
{
try
{
OnlineShopping = DriverManager.getConnection("jdbc:odbc:OnlineShopping");
}
catch (SQLException error)
{
JOptionPane.showMessageDialog(null,"Error Connecting to database:\n" + error.toString());
}
}
public void createResultSet(String tableName)
{
try
{
onlineStmt = OnlineShopping.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_UPDATABLE);
onlineRs = onlineStmt.executeQuery("Select * from "+tableName+ " ;");
}
catch (SQLException error)
{
JOptionPane.showMessageDialog(null,"Error Connecting to database:\n" + error.toString());
}
}
private void writeToDB(String tableName,String columnTitle,String dataEntry)
{
try
{
createResultSet(tableName);
onlineRs.moveToInsertRow();
onlineRs.updateString(columnTitle,dataEntry);
onlineRs.insertRow();
}
catch (SQLException error)
{
JOptionPane.showMessageDialog(null,"Error Connecting to database:\n" + error.toString());
}
}
private void writeToDB(String tableName,String columnTitle,int dataEntry)
{
try
{
createResultSet(tableName);
onlineRs.moveToInsertRow();
onlineRs.updateInt(columnTitle,dataEntry);
onlineRs.insertRow();
}
catch (SQLException error)
{
JOptionPane.showMessageDialog(null,"Error Connecting to database:\n" + error.toString());
}
}
public int[] searchDB(String tableName,String columnTitle,String searchWord)
{
int searchReturn[]= new int[100];
int i=0;
try
{
createResultSet(tableName);
while (onlineRs.next())
{
if (onlineRs.getString(columnTitle).toLowerCase().contains(searchWord.toLowerCase())){
searchReturn=onlineRs.getInt(1);
i++;
}
}
}
catch (SQLException error)
{
JOptionPane.showMessageDialog(null,"Error Connecting to database:\n" + error.toString());
}
return searchReturn;
}
private class WindowHandler extends WindowAdapter
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
}
}
The main only constucts an OnlineShopping object.
