java 将日期/时间添加到 JFreeChart 图
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Adding date/time to JFreeChart graph
提问by DommyCastles
I currently have a method which queries a database for values, and plots them to a graph. The only problem is, the timevariable is a long, and results in my graph looking like this:
我目前有一种方法可以查询数据库中的值，并将它们绘制成图形。唯一的问题是，time变量很长，导致我的图表如下所示：
I want to convert it to a date format and then add it to the graph.
我想将其转换为日期格式，然后将其添加到图表中。
How can I do this?
我怎样才能做到这一点？
Here is my graph code:
这是我的图形代码：
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);
Here is my method for adding to the graph:
这是我添加到图表的方法：
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);
}
}
}
Any help would be GREATLY appreciated! Thank you!
任何帮助将不胜感激！谢谢！
EDIT: I have changed my code to this:
编辑：我已将代码更改为：
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);
And my new GetDustLevels() method:
我的新 GetDustLevels() 方法：
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);
}
}
}
回答by trashgod
Without an sscceor the desired format, I'm just guessing.
没有sscce或所需的格式，我只是猜测。
XYPlot plot = (XYPlot) chart.getPlot();
DateAxis axis = (DateAxis) plot.getDomainAxis();
axis.setDateFormatOverride(new SimpleDateFormat("dd-MMM-yyyy"));
Addendum: Looking closer, you're using ChartFactory.createXYLineChart(), which creates a NumberAxisfor the domain. Instead, use ChartFactory.createTimeSeriesChart(), which creates a DateAxisfor the domain.
附录：仔细观察，您正在使用ChartFactory.createXYLineChart()，它NumberAxis为域创建了。相反，使用ChartFactory.createTimeSeriesChart()，它会DateAxis为域创建。
Addendum: If timerepresents 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.
附录：如果time代表与 Java 相同时代的毫秒数，则Date可以使用它new Date(time.longValue())来构建数据集的RegularTimePeriod. 有一个相关的例子在这里。
