问JavaFX LineChart Hover值

EN

private static final String MINIMIZED = "MINIMIZED";
private static final String MAXIMIZED = "MAXIMIZED";
private static String chartState = MINIMIZED;
// 12 Month Sales Chart
XYChart.Series<String, Number> series = new XYChart.Series<>();
XYChart.Series<String, Number> series2 = new XYChart.Series<>();

public void getDeltaData() {

    try {
        Connection con = DriverManager.getConnection(connectionUrl);
        //Get all records from table
        String SQL = "";
        Statement stmt = con.createStatement();

        //Create the result set from query execution.
        ResultSet rs = stmt.executeQuery(SQL);

        while (rs.next()) {

            series.getData().add(new XYChart.Data<String, Number>(rs.getString(1),
                    Double.parseDouble(rs.getString(7))));
            series2.getData().add(new XYChart.Data<String, Number>(rs.getString(1),
                    Double.parseDouble(rs.getString(8))));

        }
        rs.close();
        stmt.close();

    } catch (Exception e) {
    }
    yearChart = createChart();
}

    protected LineChart<String, Number> createChart() {
    final CategoryAxis xAxis = new CategoryAxis();
    final NumberAxis yAxis = new NumberAxis();

    // setup chart
    series.setName("Target");
    series2.setName("Actual");
    xAxis.setLabel("Period");
    yAxis.setLabel("£");

    yearChart.getData().add(series);
    yearChart.getData().add(series2);

    yearChart.setCreateSymbols(false);

    return yearChart;
}