将日期/时间添加到JFreeChart图表 [英] Adding date/time to JFreeChart graph

问题描述

我目前有一个查询数据库值的方法，并将它们绘制成图形。唯一的问题是，时间变量很长，导致我的图形看起来像这样：

I currently have a method which queries a database for values, and plots them to a graph. The only problem is, the time variable is a long, and results in my graph looking like this:

< img src =https://i85.photobucket.com/albums/k52/Dommmminic/graph.jpgalt =graph>

我想转换它到日期格式，然后将其添加到图表中。

I want to convert it to a date format and then add it to the graph.

我该怎么做？

这是我的图表代码：

private Long time;
private Long intensity;
public XYSeries series = new XYSeries("Sensor");
private XYDataset xyDataset;
public JFreeChart chart;

xyDataset = new XYSeriesCollection(series);
chart = ChartFactory.createXYLineChart("Sensor Data", "Time", "Intensity", xyDataset, PlotOrientation.VERTICAL, true, true, false);

以下是我添加到图表的方法：

Here is my method for adding to the graph:

public void GetDustLevels() {
    series.clear();
    try {
        currentSensor = Application.getInstance().getMinesite().getSensors().get(sensorID);
    } catch (Exception e1) {
        e1.printStackTrace();
    }

    if (currentSensor != null) {
        sensorKDTree = currentSensor.getSensorData();
        Iterator<Map.Entry<GenericPoint<Long>, String>> allPoints = sensorKDTree.iterator(sensorKDTree.getMin(null), sensorKDTree.getMax(null));

        while (allPoints.hasNext()) {
            GenericPoint<Long> timeIntensityPair = allPoints.next().getKey();
            time = timeIntensityPair.getCoord(0);
            intensity = timeIntensityPair.getCoord(1);
            System.out.println("CURRENT SENSOR" + currentSensor);
            System.out.println("TIME: " + time + " " + "INTENSITY: " + intensity);
            series.add(time, intensity);
        }

    }


}

任何帮助都将非常感谢！谢谢！

Any help would be GREATLY appreciated! Thank you!

编辑：我已将我的代码更改为：

I have changed my code to this:

public TimeSeries series = new TimeSeries("Sensor", Date.class);
public JFreeChart chart;
private Long time;
private Long intensity;

TimeSeriesCollection xyDataset = new TimeSeriesCollection(series);
chart = ChartFactory.createTimeSeriesChart("Sensor Data", "Time", "Intensity", xyDataset, true, true, false);

我的新GetDustLevels（）方法：

And my new GetDustLevels() method:

 public void GetDustLevels() {
    series.clear();
    try {
        currentSensor = Application.getInstance().getMinesite().getSensors().get(sensorID);
    } catch (Exception e1) {
        e1.printStackTrace();
    }

    if (currentSensor != null) {
        sensorKDTree = currentSensor.getSensorData();
        Iterator<Map.Entry<GenericPoint<Long>, String>> allPoints = sensorKDTree.iterator(sensorKDTree.getMin(null), sensorKDTree.getMax(null));

        while (allPoints.hasNext()) {
            GenericPoint<Long> timeIntensityPair = allPoints.next().getKey();
            time = timeIntensityPair.getCoord(0);
            intensity = timeIntensityPair.getCoord(1);
            System.out.println("CURRENT SENSOR" + currentSensor);
            System.out.println("TIME: " + time + " " + "INTENSITY: " + intensity);
            XYPlot plot = (XYPlot) chart.getPlot();
            DateAxis axis = (DateAxis) plot.getDomainAxis();
            axis.setDateFormatOverride(new SimpleDateFormat("dd-MMM-yyyy"));
            series.add(new Date(time.longValue()), intensity);
        }

    }


}

推荐答案

没有 sscce 或所需的格式，我只是在猜测。

Without an sscce or the desired format, I'm just guessing.

XYPlot plot = (XYPlot) chart.getPlot();
DateAxis axis = (DateAxis) plot.getDomainAxis();
axis.setDateFormatOverride(new SimpleDateFormat("dd-MMM-yyyy"));

附录：仔细观察，你正在使用 ChartFactory.createXYLineChart（），为域创建 NumberAxis 。相反，使用 ChartFactory.createTimeSeriesChart（），为域创建 DateAxis 。

Addendum: Looking closer, you're using ChartFactory.createXYLineChart(), which creates a NumberAxis for the domain. Instead, use ChartFactory.createTimeSeriesChart(), which creates a DateAxis for the domain.

附录：如果 time 表示与Java相同时期的毫秒 日期 ，你可以使用新日期（time.longValue（））构建数据集的 RegularTimePeriod 。有一个相关的例子这里。

Addendum: If time represents milliseconds from the same epoch as a Java Date, you can use new Date(time.longValue()) to construct your dataset's RegularTimePeriod. There's a related example here.

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