JFreeChart Pie Chart - JFreeChart

What is the use of pie chart in JFreecharts?

In a pie chart, arc length of each sector is proportional to the quantity which it represents. This chapter will explain you how to use JFreeChart for creating Pie Chart from a given set of business data.

Business data

Below example depicts mobile sale with the help of a pie chart. Below is a list of different mobile brands and their sale (units per day).

AWT Based Application

Below is the code for creating a Pie Chart by using the above given information This code will help you to embed a pie chart in any AWT based application.

import javax.swing.JPanel; import org.jfree.chart.ChartFactory; import org.jfree.chart.ChartPanel; import org.jfree.chart.JFreeChart; import org.jfree.data.general.DefaultPieDataset; import org.jfree.data.general.PieDataset; import org.jfree.ui.ApplicationFrame; import org.jfree.ui.RefineryUtilities; public class PieChart_AWT extends ApplicationFrame { public PieChart_AWT( String title ) { super( title ); setContentPane(createDemoPanel( )); } private static PieDataset createDataset( ) { DefaultPieDataset dataset = new DefaultPieDataset( ); dataset.setValue( "IPhone 5s" , new Double( 20 ) ); dataset.setValue( "SamSung Grand" , new Double( 20 ) ); dataset.setValue( "MotoG" , new Double( 40 ) ); dataset.setValue( "Nokia Lumia" , new Double( 10 ) ); return dataset; } private static JFreeChart createChart( PieDataset dataset ) { JFreeChart chart = ChartFactory.createPieChart( "Mobile Sales", // chart title dataset, // data true, // include legend true, false); return chart; } public static JPanel createDemoPanel( ) { JFreeChart chart = createChart(createDataset( ) ); return new ChartPanel( chart ); } public static void main( String[ ] args ) { PieChart_AWT demo = new PieChart_AWT( "Mobile Sales" ); demo.setSize( 560 , 367 ); RefineryUtilities.centerFrameOnScreen( demo ); demo.setVisible( true ); } }

Let’s place the above Java code in PieChart_AWT.java file, and then compile and run it from the command prompted as

$javac PieChart_AWT.java $java PieChart_AWT

If everything works fine, it will compile and run to generate below Pie Graph

If you don’t want to embed your chart in any application, then you can create chart images in the command prompt. JFreeChart allows saving chart images in either JPG or PNG formats.

JPEG Image Creation

Let’s re-write the above example to generate a JPEG image from a command line. Below are the two APIs provided by JFreeChart library, which can be used for generating either PNG or JPEG image based on your requirement.

• saveChartAsPNG() − API to save image in PNG format.
• saveChartAsJPEG() − API to save image in JPEG format.

import java.io.*; import org.jfree.chart.ChartUtilities; import org.jfree.chart.ChartFactory; import org.jfree.chart.JFreeChart; import org.jfree.data.general.DefaultPieDataset; public class PieChart { public static void main( String[ ] args ) throws Exception { DefaultPieDataset dataset = new DefaultPieDataset( ); dataset.setValue("IPhone 5s", new Double( 20 ) ); dataset.setValue("SamSung Grand", new Double( 20 ) ); dataset.setValue("MotoG", new Double( 40 ) ); dataset.setValue("Nokia Lumia", new Double( 10 ) ); JFreeChart chart = ChartFactory.createPieChart( "Mobile Sales", // chart title dataset, // data true, // include legend true, false); int width = 640; /* Width of the image */ int height = 480; /* Height of the image */ File pieChart = new File( "PieChart.jpeg" ); ChartUtilities.saveChartAsJPEG( pieChart , chart , width , height ); } }

keep the above Java code in PieChart.java file, and then compile and run it from the command prompted as

$javac PieChart.java $java PieChart

If everything is working fine, it will compile and run to create a JPEG image file named PieChart.jpeg in your current directory.