本章演示如何使用JFreeChart從一個給定的業務數據創建氣泡圖表。使用氣泡圖顯示在三維方式的信息。氣泡繪製在其中(x，y)坐標相交的地方。氣泡的大小被認為是範圍或X和Y軸的數量。

業務數據

考慮不同的人的年齡，體重和工作能力可能不太相同。能力可以視為對該被繪製為圖表中的氣泡的小時數。

WEIGHT
AGE		30	40	50	60	70	80
	10	4						WORK
	20		5
	30			10
	40				8
	50					9
	60						6

基於AWT的應用

以下是對從上述給定的信息創建氣泡圖表的代碼。此代碼可以幫助嵌入一個氣泡圖在AWT應用程序。

import java.awt.Color; 
import java.awt.Dimension; 
import javax.swing.JPanel; 
import org.jfree.chart.*; 
import org.jfree.chart.axis.NumberAxis; 
import org.jfree.chart.plot.PlotOrientation; 
import org.jfree.chart.plot.XYPlot; 
import org.jfree.chart.renderer.xy.XYItemRenderer; 
import org.jfree.data.xy.DefaultXYZDataset; 
import org.jfree.data.xy.XYZDataset; 
import org.jfree.ui.ApplicationFrame; 
import org.jfree.ui.RefineryUtilities;
  
public class BubbleChart_AWT extends ApplicationFrame
{
   public BubbleChart_AWT( String s )
   {
      super( s );                 
      JPanel jpanel = createDemoPanel( );                 
      jpanel.setPreferredSize(new Dimension( 560 , 370 ) );                 
      setContentPane( jpanel ); 
   }

   private static JFreeChart createChart( XYZDataset xyzdataset )
   {
      JFreeChart jfreechart = ChartFactory.createBubbleChart(
         "AGE vs WEIGHT vs WORK",                    
         "Weight",                    
         "AGE",                    
         xyzdataset,                    
         PlotOrientation.HORIZONTAL,                    
         true, true, false);
         
      XYPlot xyplot = ( XYPlot )jfreechart.getPlot( );                 
      xyplot.setForegroundAlpha( 0.65F );                 
      XYItemRenderer xyitemrenderer = xyplot.getRenderer( );
      xyitemrenderer.setSeriesPaint( 0 , Color.blue );                 
      NumberAxis numberaxis = ( NumberAxis )xyplot.getDomainAxis( );                 
      numberaxis.setLowerMargin( 0.2 );                 
      numberaxis.setUpperMargin( 0.5 );                 
      NumberAxis numberaxis1 = ( NumberAxis )xyplot.getRangeAxis( );                 
      numberaxis1.setLowerMargin( 0.8 );                 
      numberaxis1.setUpperMargin( 0.9 );
                     
      return jfreechart;
   }

   public static XYZDataset createDataset( )
   {
      DefaultXYZDataset defaultxyzdataset = new DefaultXYZDataset(); 
                     
      double ad[ ] = { 30 , 40 , 50 , 60 , 70 , 80 };                 
      double ad1[ ] = { 10 , 20 , 30 , 40 , 50 , 60 };                 
      double ad2[ ] = { 4 , 5 , 10 , 8 , 9 , 6 };                 
      double ad3[][] = { ad , ad1 , ad2 };                 
      defaultxyzdataset.addSeries( "Series 1" , ad3 );
                   
      return defaultxyzdataset; 
   }

   public static JPanel createDemoPanel( )
   {
      JFreeChart jfreechart = createChart( createDataset( ) );                 
      ChartPanel chartpanel = new ChartPanel( jfreechart );
                       
      chartpanel.setDomainZoomable( true );                 
      chartpanel.setRangeZoomable( true );
                 
      return chartpanel;
   }

   public static void main( String args[ ] )
   {
      BubbleChart_AWT bubblechart = new BubbleChart_AWT( "Bubble Chart_frame" );   
                    
      bubblechart.pack( );                 
      RefineryUtilities.centerFrameOnScreen( bubblechart );                 
      bubblechart.setVisible( true ); 
   }
}

讓我們保存上麵的Java代碼在BubbleChart_AWT.java文件，然後從命令提示符下編譯並運行它，如下所示：

$javac BubbleChart_AWT.java 
$java BubbleChart_AW

如果一切順利，它會編譯並運行生成以下氣泡圖：

創建JPEG圖像

讓我們重新編寫上麵的例子，在命令行生成JPEG圖像。

import java.io.*;
import java.awt.Color; 
import org.jfree.chart.*; 
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYItemRenderer;
import org.jfree.data.xy.DefaultXYZDataset;
import org.jfree.chart.ChartUtilities;

public class BubbleChart_image
{
   public static void main( String args[ ] )throws Exception
   {
      DefaultXYZDataset defaultxyzdataset = new DefaultXYZDataset( );
      double ad[ ] = { 30 , 40 , 50 , 60 , 70 , 80 };
      double ad1[ ] = { 10 , 20 , 30 , 40 , 50 , 60 };
      double ad2[ ] = { 4 , 5 , 10 , 8 , 9 , 6 };
      double ad3[ ][ ] = { ad , ad1 , ad2 };
      defaultxyzdataset.addSeries( "Series 1" , ad3 );

      JFreeChart jfreechart = ChartFactory.createBubbleChart(
         "AGE vs WEIGHT vs WORK", 
         "Weight", 
         "AGE", 
         defaultxyzdataset, 
         PlotOrientation.HORIZONTAL, 
         true, true, false);

      XYPlot xyplot = ( XYPlot )jfreechart.getPlot( );
      xyplot.setForegroundAlpha( 0.65F );
      XYItemRenderer xyitemrenderer = xyplot.getRenderer( );
      xyitemrenderer.setSeriesPaint( 0 , Color.blue );
      NumberAxis numberaxis = ( NumberAxis )xyplot.getDomainAxis( );
      numberaxis.setLowerMargin( 0.2 );
      numberaxis.setUpperMargin( 0.5 );
      NumberAxis numberaxis1 = ( NumberAxis )xyplot.getRangeAxis( );
      numberaxis1.setLowerMargin( 0.8 );
      numberaxis1.setUpperMargin( 0.9 );

      int width = 560; /* Width of the image */
      int height = 370; /* Height of the image */ 
      File bubbleChart = new File("BubbleChart.jpeg"); 
      ChartUtilities.saveChartAsJPEG(bubbleChart,jfreechart,width,height);
   }
}

讓我們保存上麵的Java代碼在BubbleChart_image.java文件，然後從命令提示符下編譯並運行它，如下所示：

$javac BubbleChart_image.java 
$java BubbleChart_image 

如果一切順利，它會編譯並運行在當前的目錄中創建的JPEG圖像文件namedBubbleChart.jpeg。