JFreeChart调用技术文档(JSP页面实现折线图)

创建柱状图1 引入jFreechart的包jcommon-1.0.15.jarjfreechart-1.0.12.jarjfreechart-1.0.12-experimental.jar2 在web.xml中加入<servlet><servlet-nam e>DisplayChart</servlet-nam e><servlet-class>org.jfree.chart.servlet.DisplayChart</servlet-class></servlet><servlet-m apping><servlet-nam e>DisplayChart</servlet-nam e><url-pattern>/servlet/DisplayChart</url-pattern></servlet-m apping>3 在jsp或者servlet或者action中写// 创建一个柱状图DefaultCategoryDataset dataSet =new DefaultCategoryDataset();// 数据装入for(int i=0;i<list.size();i++){Item item =(Item)list.get(i);dataSet.setValue(Item.getRating(), "testNam e", Item.getTime());}JFreeChart chart = ChartFactory.createBarChart("统计图","ratings", "time", dataSet, PlotOrientation.VERTICAL,false, true, false);try{String filename = ServletUtilities.saveChartAsPNG(chart, 500, 300, null, ses sion);String graphURL = request.getContextPath() + "/servlet/DisplayChart?filen am e=" + filename;request.setAttribute("graphURL",graphURL);} catch (Exception e){}4 在页面引入<img src="<%= request.getAttribute("graphURL") %>">这种方式会生成临时图片文件，默认是不对其进行清理的，所以要手工进行处理对于临时文件的清除，jfreechart提供了一个实现了HttpSessionBindingListener的类Chart Deleter，里面有个valueUnbound方法，这个方法是在session执行remove的时候被自动执行，所以我们只需要在页面刚进入的时候调用session.removeAttribute("JFreeChart_Deleter");这样会删除当前session之前生成的图表。

还有一种方法是用流输出的方式，直接，即：注释掉上面的try中的代码，加入如下代码ChartUtilities.writeChartAsJPEG(response.getOutputStream(),chart,500,300);然后在显示页面引入该jsp或者servlet<img src="<%=request.getContextPath()%>/servlet">简单的折线图就是把createBarChart方法换成createLineChart方法，高级特性请参见JFreeChart的文档页面动态JFreechart<% tuxingCanShu TXCS= (tuxingCanShu)request.getAttribute("TXCS");YoungRepository youngEM=(YoungRepository)request.getSession().getAttribute("DB2");String diqu=(String) request.getSession().getAttribute("diqu");String JCDBM=TXCS.getJCDBM();String LB=TXCS.getLB();String YZBM=TXCS.getYZBM();String Begintime=TXCS.getBegintime();String Endtime=TXCS.getEndtime();LSSJ_Boimp LSSJB=new LSSJ_Boimp();ArrayList<LiShi> ls=LSSJB.FindLiShi_yearMooth(youngEM, JCDBM, LB, YZBM, Begintime, Endtime, diqu);DIC_XTYZ_BoImp DXB=new DIC_XTYZ_BoImp();DIC_JCYZ dj=DXB.findDIC_JCYZ(youngEM, YZBM);List<LiShi> lstemp=new ArrayList<LiShi>();if(ls.size()>20){lstemp= ls.subList(0,20);}else{lstemp=ls;}if(!lstemp.isEmpty()&&lstemp!=null){DefaultCategoryDataset dataset = new DefaultCategoryDataset();int i=0;for(LiShi templs:lstemp){if(i%9==0){String series1 =dj.getJCYZ_MC();// 横轴名称(列名称)String type = templs.getDatatime().substring(11,16);String avlue=templs.getAvgAValue();double EMSvalue=Double.parseDouble(avlue);dataset.addValue(EMSvalue, series1, type);}else{String series1 =dj.getJCYZ_MC();String type = templs.getDatatime().substring(11, 16);String avlue=templs.getAvgAValue();double EMSvalue=Double.parseDouble(avlue);dataset.addValue(EMSvalue, series1, type);}i++;}//--------------------------------数据集建立完毕-----------------------------//建立chartJFreeChart chart = ChartFactory.createLineChart("", // chart title"时间", // domain axis label"", // range axis labeldataset, // dataPlotOrientation.VERTICAL, // orientationtrue, // include legendtrue, // tooltipsfalse// urls);// NOW DO SOME OPTIONAL CUSTOMISATION OF THE CHART...chart.getLegend().setItemFont(new Font("宋体", Font.BOLD, 12));CategoryPlot plot = chart.getCategoryPlot();// customise the range axis...plot.setDomainGridlinePaint(Color.white);//设置网格竖线(Domain轴)颜色plot.setDomainGridlinesVisible(true);NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis();rangeAxis.setLabelFont(new Font("宋体", Font.BOLD, 12));rangeAxis.setStandardTickUnits(NumberAxis.createIntegerTickU nits());rangeAxis.setAutoRangeIncludesZero(true);rangeAxis.setUpperMargin(0.20);rangeAxis.setLabelAngle(Math.PI / 2.0);CategoryAxis axis = (CategoryAxis) plot.getDomainAxis();axis.setLabelFont(new Font("宋体", Font.BOLD, 12));axis.setCategoryLabelPositions(CategoryLabelPositions.UP_45);//倾斜45度LineAndShapeRenderer renderer = (LineAndShapeRenderer) plot.getRenderer(); renderer.setItemLabelGenerator(new StandardCategoryItemLabelGenerator());//显示折点数据renderer.setItemLabelsVisible(true);if (renderer instanceof LineAndShapeRenderer ) {LineAndShapeRenderer renderer1 = (LineAndShapeRenderer ) renderer;renderer1.setBaseShapesVisible(true);renderer1.setBaseShapesFilled(true);renderer1.setShapesVisible(true);//设置曲线是否显示数据点 }String filename = ServletUtilities.saveChartAsPNG(chart, 700, 400, null, session);String graphURL = request.getContextPath() + "/servlet/DisplayChart?filename=" + filename;%><img src="<%=graphURL %>" width=700height=400border=0usemap="#<%=filename %>"><%} %>。