Why is the data in a timeseriescollection chart don't appear correctly?

问题

I'm made a chart timeseriescollection type. I'm fetching the following values to the database.

However when creating the graph, the values shown are not entirely accurate. Can someone tell me why this happens?

Only shows the date. Hours not appear correctly. Does anyone can help me solve this little problem please? I would be eternally grateful.

Thank you all very much.

Values from Database.

select (CONCAT(data_registo, ' ', hora_registo)) as data,  temperatura from registos where idSensor like 'Thermomether001' and data_registo between '2014-07-20' and '2014-07-24'

2014-07-20 00:26:03 19.4
2014-07-20 00:55:07 18.4
2014-07-20 01:58:14 18.4
2014-07-20 03:03:02 18.4
2014-07-20 04:40:13 19.3
2014-07-20 05:10:56 18.4
2014-07-20 05:41:40 19.3
. 
.
.
2014-07-24 21:40:04 19.3
2014-07-24 22:09:42 19.2
2014-07-24 22:39:20 18.9
2014-07-24 23:02:19 19.8
2014-07-24 23:38:37 19.7

Chart

As you can see only shows the date. The time that appears is not registered in the database. Can anyone help me?

Code of chart

JFreeChart createChart(XYDataset dataset) {

    JFreeChart chart = ChartFactory.createTimeSeriesChart(
        "Chart",  // title
        "Date",             // x-axis label
        "Temperature",     // y-axis label
        dataset,            // data
        true,               // create legend?
        true,               // generate tooltips?
        false               // generate URLs?
    );


    XYPlot plot = (XYPlot) chart.getPlot();


    DateAxis axis = (DateAxis) plot.getDomainAxis();
    axis.setDateFormatOverride(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));

    return chart;

}


 XYDataset createDataset() throws SQLException, ParseException {
    Connection con = null;
    String databaseURL = "jdbc:sqlserver://-----;IntegratedSecurity=true";
    String driverName = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
    try {
        Class.forName(driverName).newInstance();
    } catch (Exception ex) {
        System.out.println("");
    }

        con = (Connection) DriverManager.getConnection(databaseURL);

        if (!con.isClosed()) {
            System.out.println("Successfully connected to the DataBase Server...");
        }

       SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String d1 = sdf.format(jDateChooser1.getDate());
        String d2 = sdf.format(jDateChooser2.getDate());
        String c1 = jComboBoxSensores.getSelectedItem().toString();

        Statement statement;
        statement = (Statement) con.createStatement();
        String selectQuery ="select (CONCAT(data_registo, ' ', hora_registo)) as data,  temperatura from registos where idSensor like '"+c1+"' and temperatura not in ('0.0') and data_registo between '"+d1+"' and '"+d2+"'";
        ResultSet resultSet = null;
        resultSet = statement.executeQuery(selectQuery);

    TimeSeries s1 = new TimeSeries(c1);
    while (resultSet.next()) {

                String data = (String) resultSet.getObject("data");
                String temperatura = (String) resultSet.getObject("temperatura");

                SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                Date dateI = sdf2.parse(data);

                double value = Double.parseDouble(temperatura);



               s1.addOrUpdate(new Hour(dateI), value);               

            } 

           resultSet.close();


    TimeSeriesCollection dataset = new TimeSeriesCollection();

    dataset.addSeries(s1);

       return dataset;


 }

 JPanel createDemoPanel() throws SQLException, ParseException {
    JFreeChart chart = createChart(createDataset());
    ChartPanel panel = new ChartPanel(chart);
    panel.setFillZoomRectangle(true);
    panel.setMouseWheelEnabled(true);
    return panel;
}

}

As you can see only shows the date. The time that appears is not registered in the database. Can anyone help me?

Very thanks everyone.

回答1:

You're truncating dateI to the nearest hour. Instead, use Second to preserve the full resolution retrieved from the query and store the result in the model.

s1.addOrUpdate(new Second(dateI), value);

In the view, you can setDateFormatOverride() to the desired format on the domain axis, as shown here.

axis.setDateFormatOverride(new SimpleDateFormat("yyyy-MM-dd HH"));

来源：https://stackoverflow.com/questions/24994704/why-is-the-data-in-a-timeseriescollection-chart-dont-appear-correctly

标签

java

netbeans

jfreechart

timeserieschart