jfreechart柱状图

import java.io.File;     
import java.io.FileNotFoundException;     
import java.io.FileOutputStream;     
import java.io.IOException;     
    
import org.jfree.chart.ChartFactory;     
import org.jfree.chart.ChartUtilities;     
import org.jfree.chart.JFreeChart;     
import org.jfree.chart.plot.CategoryPlot;     
import org.jfree.chart.plot.PlotOrientation;     
import org.jfree.data.category.CategoryDataset;     
import org.jfree.data.general.DatasetUtilities;     
    
//JFreeChart Bar Chart（柱状图）     
public class CreateJFreeChartBar {     
    
    /**   
     * 创建JFreeChart Bar Chart（柱状图）   
     */    
    public static void main(String[] args) {     
        //步骤1：创建CategoryDataset对象（准备数据）     
        CategoryDataset dataset = createDataset();     
        //步骤2：根据Dataset 生成JFreeChart对象，以及做相应的设置     
        JFreeChart freeChart = createChart(dataset);     
        //步骤3：将JFreeChart对象输出到文件，Servlet输出流等     
        saveAsFile(freeChart, "c:\\jfreechart\\bar.png", 500, 400);     
    }     
         
    //保存为文件     
    public static void saveAsFile(JFreeChart chart, String outputPath, int weight, int height) {     
        FileOutputStream out = null;     
        try {     
            File outFile = new File(outputPath);     
            if (!outFile.getParentFile().exists()) {     
                outFile.getParentFile().mkdirs();     
            }     
            out = new FileOutputStream(outputPath);     
            //保存为PNG文件     
            ChartUtilities.writeChartAsPNG(out, chart, 300, 200);     
            //保存为JPEG文件     
            //ChartUtilities.writeChartAsJPEG(out, chart, 500, 400);     
            out.flush();     
        } catch (FileNotFoundException e) {     
            e.printStackTrace();     
        } catch (IOException e) {     
            e.printStackTrace();     
        } finally {     
            if (out != null) {     
                try {     
                    out.close();     
                } catch (IOException e) {     
                    //do nothing     
                }     
            }     
        }     
    }     
    
    //根据CategoryDataset生成JFreeChart对象     
    public static JFreeChart createChart(CategoryDataset categoryDataset) {     
        JFreeChart jfreechart = ChartFactory.createBarChart("Bar Chart Demo",    //标题     
                "产品",    //categoryAxisLabel （category轴，横轴，X轴的标签）     
                "数量",    //valueAxisLabel（value轴，纵轴，Y轴的标签）     
                categoryDataset, // dataset     
                PlotOrientation.VERTICAL,     
                true, // legend     
                false, // tooltips     
                false); // URLs     
             
        //以下的设置可以由用户定制，也可以省略     
        CategoryPlot  plot = (CategoryPlot) jfreechart.getPlot();     
        //背景色　透明度     
        plot.setBackgroundAlpha(0.5f);     
        //前景色　透明度     
        plot.setForegroundAlpha(0.5f);     
        //其它设置可以参考 CategoryPlot     
             
        return jfreechart;     
    }     
    
    /**   
     * 创建CategoryDataset对象   
     *    
     */    
    public static CategoryDataset createDataset() {     
             
        String []rowKeys = {"One", "Two", "Three"};     
        String []colKeys = {"1987", "1997", "2007"};     
             
        double [][] data = {     
                {50, 20, 30},     
                {20, 10D, 40D},     
                {40, 30.0008D, 38.24D},     
        };     
             
        //也可以使用以下代码     
        //DefaultCategoryDataset categoryDataset = new DefaultCategoryDataset();     
        //categoryDataset.addValue(10, "rowKey", "colKey");     
             
        return DatasetUtilities.createCategoryDataset(rowKeys, colKeys, data);             
    }     
    
}