Streudiagramm in jfreechart aus der Datenbank

Dieses vollständige Beispiel erstellt eine geeignete Datenbanktabelle im Speicher und fragt sie in ein JDBCXYDataset und zeigt den Datensatz in einem Streudiagramm an. Beachten Sie, wie die erste Spalte zur Domäne wird, während nachfolgende Spalten zu einzelnen Serien werden.

import java.awt.EventQueue;
import java.sql.Connection;
import java.sql.Date;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Calendar;
import java.util.Random;
import javax.swing.JFrame;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.jdbc.JDBCXYDataset;

/**
 * @see http://stackoverflow.com/a/24592754/230513
 */
public class JDBCTest {

    private static final int N = 30;
    private static final Random r = new Random();

    private void display() {
        JFrame f = new JFrame("JDBCTest");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JDBCXYDataset jds = createDataset();
        JFreeChart chart = ChartFactory.createScatterPlot("Inventory",
            "Date", "Count", jds, PlotOrientation.VERTICAL, true, true, false);
        XYPlot plot = chart.getXYPlot();
        plot.setDomainAxis(new DateAxis("Date"));
        f.add(new ChartPanel(chart));
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
        for (int i = 0; i < jds.getItemCount(); i++) {
            System.out.println(new Date(jds.getX(0, i).longValue()));
        }
    }

    private JDBCXYDataset createDataset() {
        try {
            Connection conn = DriverManager.getConnection(
                "jdbc:h2:mem:test", "", "");
            Statement st = conn.createStatement();
            st.execute("create table inventory(when date, n1 integer, n2 integer)");
            PreparedStatement ps = conn.prepareStatement(
                "insert into inventory values (?, ?, ?)");
            Calendar c = Calendar.getInstance();
            for (int i = 0; i < N; i++) {
                ps.setDate(1, new Date(c.getTimeInMillis()));
                ps.setInt(2, N / 3 + r.nextInt(N / 3));
                ps.setInt(3, N / 2 + r.nextInt(N / 3));
                ps.execute();
                c.add(Calendar.MONTH, 1);
            }
            JDBCXYDataset jds = new JDBCXYDataset(conn);
            jds.executeQuery("select when, n1, n2 from inventory");
            return jds;
        } catch (SQLException ex) {
            ex.printStackTrace(System.err);
        }
        return null;
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new JDBCTest().display();
            }
        });
    }
}