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