Reading ResultSet into JTable (over different classes)

Question

So in my program I'm trying to read the data inside my resultset which I used to get data from my database with a PreparedStatement. I'm using the MVC model and the DAO pattern which made me kinda get lost with how I have to read my resultset from one class(BTRDaoImpl) to my JTable in my View class. So far from researching it I found the best solution to be to make a custom table class, but from there on I don't know how to progress.

My custom table class:

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

import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;

public class ResultSetTable extends JTable{
 /**
 * 
 */
private static final long serialVersionUID = 1L;

private final DefaultTableModel dataModel;

  public ResultSetTable(ResultSet rs)
                       throws SQLException{

    super();
    dataModel = new DefaultTableModel();
    setModel(dataModel);

    try {
      //create an array of column names
      ResultSetMetaData mdata = rs.getMetaData();
      int colCount = mdata.getColumnCount();
      String[] colNames = new String[colCount];
      for (int i = 1; i <= colCount; i++) {
        colNames[i - 1] = mdata.getColumnName(i);
      }
      dataModel.setColumnIdentifiers(colNames);

      //get data through loop
      while (rs.next()) {
        String[] rowData = new String[colCount];
        for (int i = 1; i <= colCount; i++) {
          rowData[i - 1] = rs.getString(i);
        }
        dataModel.addRow(rowData);
      }
    }
    finally{
      try {
        rs.close();
      }
      catch (SQLException ignore) {
      }
    }
  }
}

And the relevant part of my View class:

import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTable;
import javax.swing.JTextField;

import dbconnect.dao.impl.BTRDaoImpl;

public class View extends JFrame{
public View() {

    JTable table = new JTable(new ResultSetTable(BTRDaoImpl.resultset);

    this.setSize(600, 400);
    setResizable(false);
}

My BTRDaoImpl class with the sql query and resultset:

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Collection;
import mvc.View;
import dao.BTRbDao;
import business.BTRBean;

public class BTRDaoImpl extends AbstractDao implements BTRDao {

private Connection dbConnection = null;
private PreparedStatement preparedStatement = null;

public void sqlquery() {
    try {

        String btrname = View.searchbbtrname.getText();
        String btrplz = View.searchbtrplz.getText();
        btrname = btrname.trim().toUpperCase();
        btrplz = btrplz.trim().toUpperCase();

        if (btrplz.isEmpty()) {
            String btrResult = "SELECT BBSTBBNR, BBSTNABE, BBSTPLZ FROM BP.TBBBST WHERE BBSTNABEG = ?";

            dbConnection = AbstractDao.getConnection();
            preparedStatement = dbConnection.prepareStatement(btrResult);
            preparedStatement.setString(1, btrname);


        } else {
            String btrResult = "SELECT BBSTBBNR, BBSTNABE, BBSTPLZ FROM BP.TBBBST WHERE BBSTNABEG = ? AND BBSTPLZ = ?";

            dbConnection = AbstractDao.getConnection();
            preparedStatement = dbConnection.prepareStatement(btrResult);
            preparedStatement.setString(1, btrname);
            preparedStatement.setString(2, btrplz);

        }
    } catch (SQLException e1) {
        System.out.println("An error with the SQL query occured: ");
        e1.printStackTrace();
    } 
}

public Collection<BtrBean> getBTR() throws SQLException,
        IOException {
    sqlquery();
    final Collection<BtrBean> result = new ArrayList<BtrBean>();

    ResultSet resultset = null;
    try {
        resultset = preparedStatement.executeQuery();

        // while loop to get data
        while (resultset.next()) {
            BtrBean btr = new BtrBean();
            int btrid = resultset.getInt(1);
            String btrplz = resultset.getString(3);
            String btrname = resultset.getString(2);
            btr.setBetriebnr(btrid);
            btr.setBetriebplz(btrplz);
            btr.setBetriebname(btrname);
            result.add(btr);
        //  System.out.println("BTR-ID: " + btrid + " BTR PLZ: " + btrplz + " BTR: " + btrname);
        }

    } catch (SQLException e) {
        e.printStackTrace();
        System.out.println("An error processing the SQL occured: ");
        e.printStackTrace();
    } catch (NullPointerException npe) {
        System.out.println("NullPointerException: ");
        npe.printStackTrace();
    } finally {
        if (preparedStatement != null) preparedStatement.close();
        closeConnection(resultset);
    }
    return result;
}

}

Answer 1

General way to do this:

1. Design a POJO to hold your data.
2. From the PreparedStatement, create the POJO instances and fill the data in the POJOs.
3. Create a custom TableModel class by extending from AbstractTableDataModel. Implement the getValue(int, int) method to return your data in the model.
4. Create your GUI and pass the model to your table upon construction.

Mission accomplished.