JPEG图像创建
让我们重新编写上面的例子,从命令行生成JPEG图像.
import java.io.*;import org.jfree.chart.ChartFactory;import org.jfree.chart.JFreeChart;import org.jfree.chart.plot.PlotOrientation;import org.jfree.data.category.DefaultCategoryDataset;import org.jfree.chart.ChartUtilities;public class BarChart { public static void main( String[ ] args )throws Exception { final String fiat = "FIAT"; final String audi = "AUDI"; final String ford = "FORD"; final String speed = "Speed"; final String millage = "Millage"; final String userrating = "User Rating"; final String safety = "safety"; final DefaultCategoryDataset dataset = new DefaultCategoryDataset( ); dataset.addValue( 1.0 , fiat , speed ); dataset.addValue( 3.0 , fiat , userrating ); dataset.addValue( 5.0 , fiat , millage ); dataset.addValue( 5.0 , fiat , safety ); dataset.addValue( 5.0 , audi , speed ); dataset.addValue( 6.0 , audi , userrating ); dataset.addValue( 10.0 , audi , millage ); dataset.addValue( 4.0 , audi , safety ); dataset.addValue( 4.0 , ford , speed ); dataset.addValue( 2.0 , ford , userrating ); dataset.addValue( 3.0 , ford , millage ); dataset.addValue( 6.0 , ford , safety ); JFreeChart barChart = ChartFactory.createBarChart( "CAR USAGE STATIStICS", "Category", "Score", dataset,PlotOrientation.VERTICAL, true, true, false); int width = 640; /* Width of the image */ int height = 480; /* Height of the image */ File BarChart = new File( "BarChart.jpeg" ); ChartUtilities.saveChartAsJPEG( BarChart , barChart , width , height ); }}
让我们将上述Java代码保存在BarChart.java文件中,然后从命令编译并运行它提示为 :
$ javac BarChart.java $ java BarChart
如果一切正常,它将编译并运行以在当前目录中创建名为 BarChart.jpeg 的JPEG图像文件.