JFreeChart柱状图（转）

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package com.test.jfree;

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, 300);
    }

    //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, 500, 300);
            //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.createBarChart3D("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);
    }

}