使用JFreeChart生成XY轴折线图

第一步： 

//生成折线图的处理类(其他DOMAIN类代码省略)
public class CreateJFreeChartXYLine {
    // 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
            ChartUtilities.writeChartAsPNG(out, chart,500, 400);
            // 保存为JPEG
            // 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XYDataset创建JFreeChart对象
    public static JFreeChart createChart(XYDataset dataset) {
        // 创建JFreeChart对象：ChartFactory.createXYLineChart
        JFreeChart jfreechart = ChartFactory.createTimeSeriesChart("折线模型图",
                "年份", "数量", dataset, false, true, false);
        jfreechart.getTitle().setFont(new Font("宋体", Font.BOLD, 12));
        // 使用CategoryPlot设置各种参数。以下设置可以省略。
        XYPlot plot = (XYPlot) 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XYPlot类
        ValueAxis categoryaxis = plot.getDomainAxis(); // 横轴上的
        categoryaxis.setPositiveArrowVisible(true);// 增加横轴的箭头
        plot.getRangeAxis().setPositiveArrowVisible(true);// 增加纵轴的箭头
        categoryaxis.setTickLabelFont(new Font("宋体", 10, 12));// 设定字体、类型、字号
        DateAxis axis = (DateAxis) plot.getDomainAxis();
        axis.setDateFormatOverride(new SimpleDateFormat("MM月"));
        NumberAxis numberaxis = new NumberAxis("统计报表");//侧面显示的标题
        numberaxis.setAutoRangeIncludesZero(false);
        plot.setRangeAxis(1, numberaxis);
        plot.setDataset(1, dataset);
        plot.mapDatasetToRangeAxis(1, 1);
        XYItemRenderer xyitemrenderer = plot.getRenderer();
        StandardXYItemRenderer standardxyitemrenderer1 = new StandardXYItemRenderer();
        standardxyitemrenderer1.setSeriesPaint(0, Color.black);
        standardxyitemrenderer1.setSeriesPaint(0, Color.black);
        standardxyitemrenderer1.setPlotLines(true);
        LegendTitle legendtitle = new LegendTitle(xyitemrenderer);
        LegendTitle legendtitle1 = new LegendTitle(standardxyitemrenderer1);
        BlockContainer blockcontainer = new BlockContainer(
                new BorderArrangement());
        blockcontainer.add(legendtitle, RectangleEdge.LEFT);
        blockcontainer.add(legendtitle1, RectangleEdge.RIGHT);//这两行代码可以控制位置
        blockcontainer.add(new EmptyBlock(2000D, 0.0D));
        CompositeTitle compositetitle = new CompositeTitle(blockcontainer);
        compositetitle.setPosition(RectangleEdge.BOTTOM);//放置图形代表区域位置的代码
        jfreechart.addSubtitle(compositetitle);
        Font font2 = new Font("宋体", 10, 16); // 设定字体、类型、字号
        plot.getDomainAxis().setLabelFont(font2);// 相当于横轴或理解为X轴
        plot.getRangeAxis().setLabelFont(font2);// 相当于竖轴理解为Y轴
        return jfreechart;
    }

    /**
     * 创建XYDataset对象
     *
     */
    public static XYDataset createXYDataset() {
        MyChartService ms = new MyChartService();
        // XYSeriesCollection xySeriesCollection = new XYSeriesCollection();
        TimeSeriesCollection timeseriescollection = new TimeSeriesCollection();
        List<String> names = ms.listall();
        for (String name : names) {
            System.out.println(name);
            TimeSeries timeseries = new TimeSeries(name);
            List<MyChart> mcs = ms.FindByName(name);
            for (MyChart mc : mcs) {
                Calendar cc = Calendar.getInstance();
                System.out.println(mc.getScore());
                cc.setTime(mc.getDate());
                timeseries.add(new Month(cc.get(Calendar.MONTH), cc
                        .get(Calendar.YEAR)), mc.getScore());
                // xyseries.add(mc.getDate(),mc.getScore());

            }
            // xySeriesCollection.addSeries(timeseries);
            timeseriescollection.addSeries(timeseries);

        }

        return timeseriescollection;
    }

 
第二步：如果配合Struts1使用的话

request.setCharacterEncoding("gbk");
response.setContentType("image/jpeg;charset=gbk");
MyChartService ms=new MyChartService();
//步骤1：创建XYDataset对象（准备数据）
        XYDataset dataset =CreateJFreeChartXYLine.createXYDataset();
        //步骤2：根据Dataset 生成JFreeChart对象，以及做相应的设置
        JFreeChart freeChart =CreateJFreeChartXYLine.createChart(dataset);
        //步骤3：将JFreeChart对象输出到文件，Servlet输出流等
        String url= "c:\\jfreechart\\lineXY.png";
        CreateJFreeChartXYLine.saveAsFile(freeChart,url, 900, 700);
        request.setAttribute("url", url);
        request.setAttribute("lists", ms.listall());
return mapping.findForward("list");

 
直接将路径发到JSP页面，从而达到显示图片效果