Most simple code to populate JTable from ResultSet

Question

I googled the whole day and no luck. I call getnPrintAllData() method after pressing OK button. So the code is:

public class DatabaseSQLiteConne         


        

Answer 1

Class Row will handle one row from your database.

Complete implementation of UpdateTask responsible for filling up UI.

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JTable;
import javax.swing.SwingWorker;

public class JTableUpdateTask extends SwingWorker {

    JTable      table       = null;

    ResultSet   resultSet   = null;

    public JTableUpdateTask(JTable table, ResultSet rs) {
        this.table = table;
        this.resultSet = rs;
    }

    @Override
    protected JTable doInBackground() throws Exception {
        List rows = new ArrayList();
        Object[] values = new Object[6];
        while (resultSet.next()) {
            values = new Object[6];
            values[0] = resultSet.getString("id");
            values[1] = resultSet.getString("student_name");
            values[2] = resultSet.getString("street");
            values[3] = resultSet.getString("city");
            values[4] = resultSet.getString("state");
            values[5] = resultSet.getString("zipcode");
            Row row = new Row(values);
            rows.add(row);
        }
        process(rows); 
        return this.table;
    }

    protected void process(List chunks) {
        ResultSetTableModel tableModel = (this.table.getModel() instanceof ResultSetTableModel ? (ResultSetTableModel) this.table.getModel() : null);
        if (tableModel == null) {
            try {
                tableModel = new ResultSetTableModel(this.resultSet.getMetaData(), chunks);
            } catch (SQLException e) {
                e.printStackTrace();
            }
            this.table.setModel(tableModel);
        } else {
            tableModel.getRows().addAll(chunks);
        }
        tableModel.fireTableDataChanged();
    }
}

Table Model:

import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import javax.swing.table.AbstractTableModel;

/**
 * Simple wrapper around Object[] representing a row from the ResultSet.
 */
class Row {
    private final Object[]  values;

    public Row(Object[] values) {
        this.values = values;
    }

    public int getSize() {
        return values.length;
    }

    public Object getValue(int i) {
        return values[i];
    }
}

// TableModel implementation that will be populated by SwingWorker.
public class ResultSetTableModel extends AbstractTableModel {
    private final ResultSetMetaData rsmd;

    private List               rows;

    public ResultSetTableModel(ResultSetMetaData rsmd, List rows) {
        this.rsmd = rsmd;
        if (rows != null) {
            this.rows = rows;
        } else {
            this.rows = new ArrayList();
        }

    }

    public int getRowCount() {
        return rows.size();
    }

    public int getColumnCount() {
        try {
            return rsmd.getColumnCount();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return 0;
    }

    public Object getValue(int row, int column) {
        return rows.get(row).getValue(column);
    }

    public String getColumnName(int col) {
        try {
            return rsmd.getColumnName(col + 1);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return "";
    }

    public Class getColumnClass(int col) {
        String className = "";
        try {
            className = rsmd.getColumnClassName(col);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return className.getClass();
    }

    @Override
    public Object getValueAt(int rowIndex, int columnIndex) {
        if(rowIndex > rows.size()){
            return null;
        }
        return rows.get(rowIndex).getValue(columnIndex);
    }

    public List getRows() {
        return this.rows;
    }

    public void setRows(List rows) {
        this.rows = rows;
    }
}

Main Application which builds UI and does the database connection

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTable;

public class MainApp {
    static Connection conn = null;
    static void init(final ResultSet rs) {
        JFrame frame = new JFrame();
        frame.setLayout(new BorderLayout());
        final JTable table = new JTable();
        table.setPreferredSize(new Dimension(300,300));
        table.setMinimumSize(new Dimension(300,300));
        table.setMaximumSize(new Dimension(300,300));
        frame.add(table, BorderLayout.CENTER);
        JButton button = new JButton("Start Loading");
        button.setPreferredSize(new Dimension(30,30));
        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                JTableUpdateTask jTableUpdateTask = new JTableUpdateTask(table, rs);
                jTableUpdateTask.execute();

            }
        });
        frame.add(button, BorderLayout.SOUTH);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/test";
        String driver = "com.mysql.jdbc.Driver";
        String userName = "root";
        String password = "root";
        try {
            Class.forName(driver).newInstance();
            conn = DriverManager.getConnection(url, userName, password);
            PreparedStatement pstmt = conn.prepareStatement("Select id, student_name, street, city, state,zipcode from student");
            ResultSet rs = pstmt.executeQuery();
            init(rs);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}