Create Histogram using Jfreechart


 

Create Histogram using Jfreechart

In this section, you will learn how to create histogram using jfreechart library.

In this section, you will learn how to create histogram using jfreechart library.

Create Histogram using Jfreechart

In this section, you will learn how to create histogram using jfreechart.

To create a Histogram, we have used the class  HistogramDataset. Then method addSeries()  allows to add the series of ten randomly generated numbers to the dataset, using the specified number of bins. The PlotOrientation.VERTICAL sets the vertical orientation of the Histogram. ChartFactory.createHistogram() have created the Histogram. Using the class ChartUtilities, we have converted the Histogram to image foramt(PNG). The method saveChartAsJPEG(new File("histogram.PNG") saves the chart to a file specified in PNG format.

Here is the code:

import java.io.*;
import java.util.Random;
import org.jfree.chart.*;
import org.jfree.data.statistics.*;
import org.jfree.chart.plot.PlotOrientation;

 public class HistogramExample {
       public static void main(String[] args) {
       double[] value = new double[100];
       Random generator = new Random();
       for (int i=1; i < 100; i++) {
       value[i] = generator.nextDouble();
           int number = 10;
       HistogramDataset dataset = new HistogramDataset();
       dataset.setType(HistogramType.RELATIVE_FREQUENCY);
       dataset.addSeries("Histogram",value,number);
       String plotTitle = "Histogram"; 
       String xaxis = "number";
       String yaxis = "value"; 
       PlotOrientation orientation = PlotOrientation.VERTICAL; 
       boolean show = false; 
       boolean toolTips = false;
       boolean urls = false; 
       JFreeChart chart = ChartFactory.createHistogram( plotTitle, xaxis, yaxis, 
                dataset, orientation, show, toolTips, urls);
       int width = 500;
       int height = 300; 
        try {
        ChartUtilities.saveChartAsPNG(new File("histogram.PNG"), chart, width, height);
        } catch (IOException e) {}
         }
   }
 }

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