java类中生成jfreechart,返回图表的url地址

web.xml中设置：

<servlet> <servlet-name>DisplayChart</servlet-name> <servlet-class>org.jfree.chart.servlet.DisplayChart</servlet-class> </servlet > <servlet-mapping> <servlet-name>DisplayChart</servlet-name> <url-pattern>/DisplayChart</url-pattern> </servlet-mapping>

java类中方法：

public String getChart(String series[],double score[][],String type[],String name){ final int num=8;DefaultCategoryDataset defaultcategorydataset = new DefaultCategoryDataset();for(int i=0;i<type.length;i++){type[i]=type[i].substring(0, (type[i].length()<num)?type[i].length():num);}

for(int j=0;j<series.length;j++){int i=0;for( i=0;i<type.length;i++){defaultcategorydataset.addValue(score[j][i], series[j], type[i]);}}

JFreeChart jfreechart = ChartFactory.createLineChart(name,null,null,defaultcategorydataset,PlotOrientation.VERTICAL,true,true,false);

jfreechart.getLegend().setPosition(RectangleEdge.RIGHT);

jfreechart.setBackgroundPaint(Color.white);

CategoryPlot categoryplot = (CategoryPlot)jfreechart.getPlot();categoryplot.setNoDataMessage(“无数据可供显示！”);categoryplot.setBackgroundPaint(Color.white);categoryplot.setDomainGridlinesVisible(true); categoryplot.setRangeGridlinesVisible(true);categoryplot.setRangeGridlinePaint(Color.gray);categoryplot.setDomainGridlinePaint(Color.gray);categoryplot.setBackgroundAlpha(0.8f);Font font1 = new Font(“黑体”,Font.BOLD, 14);jfreechart.getTitle().setFont(font1);

Font font3 = new Font(“隶书”,Font.BOLD, 12);jfreechart.getLegend().setItemFont(font3);

CategoryAxis categoryaxis = categoryplot.getDomainAxis(); //categoryaxis.setCategoryLabelPositions(CategoryLabelPositions.UP_45);categoryaxis.setMaximumCategoryLabelLines(10);//行数，香港服务器，服务器空间，根据需要自己设categoryaxis.setMaximumCategoryLabelWidthRatio(0.5f);//每行宽度，香港服务器，这里设一个汉字宽

NumberAxis numberaxis = (NumberAxis)categoryplot.getRangeAxis();numberaxis.setStandardTickUnits(NumberAxis.createIntegerTickUnits());numberaxis.setAutoRangeIncludesZero(true);numberaxis.setRangeWithMargins(0, 3); numberaxis.setUpperMargin(0.8);////设置最高的一个 Item 与图片顶端的距离numberaxis.setUpperBound(3.5);//纵坐标最大值categoryaxis.setTickLabelFont(new Font(“宋体”, Font.BOLD, 12));numberaxis.setTickLabelFont(new Font(“隶书”, Font.BOLD, 12));Font font2 = new Font(“SimSun”, Font.BOLD, 16);categoryaxis.setLabelFont(font2);numberaxis.setLabelFont(font2);categoryplot.setAxisOffset(new RectangleInsets(0D, 0D,0D, 10D));//设置曲线图与xy轴的距离LineAndShapeRenderer lineandshaperenderer = (LineAndShapeRenderer)categoryplot.getRenderer();lineandshaperenderer.setShapesVisible(true); //数据点可见

lineandshaperenderer.setSeriesStroke(0, new BasicStroke(2.0F, 1, 1, 1.0F, new float[] {10F, 6F}, 0.0F)); //定义series点之间的连线 ，这里是虚线，默认是直线lineandshaperenderer.setSeriesStroke(1, new BasicStroke(2.0F, 1, 1, 1.0F, new float[] {6F, 6F}, 0.0F));

lineandshaperenderer.setBaseItemLabelsVisible(true); lineandshaperenderer.setBaseItemLabelGenerator(new StandardCategoryItemLabelGenerator());

ChartRenderingInfo info=new ChartRenderingInfo(new StandardEntityCollection());String fileName = null; try { fileName = ServletUtilities.saveChartAsPNG(jfreechart, 700,300, info, null);//生成图片 } catch (IOException e) { e.printStackTrace(); }

String graphURL = “/projectname/DisplayChart?filename=” + fileName; //projectname为对应项目的路径path,一般就是项目名称

//jsp中这样使用：String graphURL = request.getContextPath() + “/DisplayChart?filename=” + filename;return graphURL;//返回生成图片的地址}

调用上述方法得到生成的chart的url：

　　 getChart(stus,score_field,type,”总分图”);

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