JFreeChart最佳實踐：散點圖
作者：遠去的渡口
本文將介紹作者通過Java最佳圖形解決方案JFreeChart實現散點圖的詳細過程。
用JfreeChart畫散點圖，查看JfreeChart的Demo，寫的都挺復雜的，關鍵是Demo中把簡單的事情復雜化了，比如展示的例子是一個正弦曲線什么的，讓初次畫散點圖的我們摸不著頭腦。關鍵是他們得到數據集搞得太過復雜，后來想明白了，不就是二維數組嘛。想通了這一點，一切問題都解決了，不過，對于我們項目的特殊要求，并不是只畫幾個點那么簡單，還要加上區域范圍與文字說明，在查看文檔及自己摸索下，2天時間，終于搞定。下面分享一下成果，呵，還是有點成就感的。
首先，看畫圖的API，參數有：
ChartFactory.createScatterPlot（），其中，有一個xydataset，那么，我們先要知道這個xydataset是什么結構的，再看所需xydataset，散點圖，也就是單獨畫出點，也就是一個二維數據了，x ，y坐標嘛！
那么，先做好準備工作，***步，拿數據，這就不用啰嗦了，就是得到一個List也好，Set也行。
第二步，加載到數據集：
- /**
- *
- * @param xydatalist
- * @param bloods
- * @return
- */
- public static XYDataset createxydataset(List<PressureBean> xydatalist,
- String bloods) {
- DefaultXYDataset xydataset = new DefaultXYDataset();
- int size = xydatalist.size();
- double[][] datas = new double[2][size];
- for (int i = 0; i < size; i++) {
- PressureBean pres = xydatalist.get(i);
- int sys = pres.getSyspress();//收縮壓
- int dia = pres.getDiapress();//舒張壓
- datas[0][i] = sys;
- datas[1][i] = dia;
- }
- xydataset.addSeries(bloods, datas);
- return xydataset;
- }
下一步，另外一個準備工作，畫圖方法：
- public static JFreeChart createChart(XYDataset xydataset,
- String bloodcattile, String shou, String shu, String nobloodData,
- String bloods, String nomal, String fore, String one, String two,
- List<PressureBean> list, Log log) {
- // 有可能用戶在后面的版本中故意輸入不正常數值，但是為了保證圖片畫圖的完整，這里先計算
- // 用戶血壓值的***值。
- int maxpress = 160;
- int addmax = 20;
- if (list != null && list.size() > 0) {
- Iterator<PressureBean> it = list.iterator();
- while (it.hasNext()) {
- PressureBean pres = it.next();
- if (maxpress < pres.getDiapress()) {
- maxpress = pres.getDiapress();
- }
- if (maxpress < pres.getSyspress()) {
- maxpress = pres.getSyspress();
- }
- }
- maxpress += addmax;
- log.info("high press value is =" + maxpress);
- }
- JFreeChart jfreechart = ChartFactory.createScatterPlot(bloodcattile,
- shou, shu, xydataset, PlotOrientation.VERTICAL, true, false,
- false);
- jfreechart.setBackgroundPaint(Color.white);
- jfreechart.setBorderPaint(Color.GREEN);
- jfreechart.setBorderStroke(new BasicStroke(1.5f));
- XYPlot xyplot = (XYPlot) jfreechart.getPlot();
- xyplot.setNoDataMessage(nobloodData);
- xyplot.setNoDataMessageFont(new Font("", Font.BOLD, 14));
- xyplot.setNoDataMessagePaint(new Color(87, 149, 117));
- xyplot.setBackgroundPaint(new Color(255, 253, 246));
- ValueAxis vaaxis = xyplot.getDomainAxis();
- vaaxis.setAxisLineStroke(new BasicStroke(1.5f));
- ValueAxis va = xyplot.getDomainAxis(0);
- va.setAxisLineStroke(new BasicStroke(1.5f));
- va.setAxisLineStroke(new BasicStroke(1.5f)); // 坐標軸粗細
- va.setAxisLinePaint(new Color(215, 215, 215)); // 坐標軸顏色
- xyplot.setOutlineStroke(new BasicStroke(1.5f)); // 邊框粗細
- va.setLabelPaint(new Color(10, 10, 10)); // 坐標軸標題顏色
- va.setTickLabelPaint(new Color(102, 102, 102)); // 坐標軸標尺值顏色
- ValueAxis axis = xyplot.getRangeAxis();
- axis.setAxisLineStroke(new BasicStroke(1.5f));
- XYLineAndShapeRenderer xylineandshaperenderer = (XYLineAndShapeRenderer) xyplot
- .getRenderer();
- xylineandshaperenderer.setSeriesOutlinePaint(0, Color.WHITE);
- xylineandshaperenderer.setUseOutlinePaint(true);
- NumberAxis numberaxis = (NumberAxis) xyplot.getDomainAxis();
- numberaxis.setAutoRangeIncludesZero(false);
- numberaxis.setTickMarkInsideLength(2.0F);
- numberaxis.setTickMarkOutsideLength(0.0F);
- numberaxis.setAxisLineStroke(new BasicStroke(1.5f));
- numberaxis.setUpperBound(maxpress);
- numberaxis.setLowerBound(60);//最小值設置為60
- NumberAxis numberaxis1 = (NumberAxis) xyplot.getRangeAxis();
- numberaxis1.setTickMarkInsideLength(2.0F);
- numberaxis1.setTickMarkOutsideLength(0.0F);
- numberaxis1.setUpperBound(105d);
- numberaxis1.setLowerBound(35);
- numberaxis1.setAxisLineStroke(new BasicStroke(1.5f));
- // if (xydataset != null) {
- XYBoxAnnotation box = new XYBoxAnnotation(0, 0, 89, 59); //正常血壓所在區域內邊界
- XYBoxAnnotation box1 = new XYBoxAnnotation(0, 0, 119, 79);//高血壓前期所在區域內邊界
- XYBoxAnnotation box2 = new XYBoxAnnotation(0, 0, 139, 89);//高血壓一期所在區域內邊界
- XYBoxAnnotation box3 = new XYBoxAnnotation(0, 0, 159, 99);//高血壓二期所在區域內邊界
- XYTextAnnotation text1 = new XYTextAnnotation(nomal, 70, 62.5);//標識“正常”
- XYTextAnnotation text = new XYTextAnnotation(fore, 70, 82.5);//“高血壓前期”
- XYTextAnnotation text2 = new XYTextAnnotation(one, 70, 91.5);//“高血壓一期”
- XYTextAnnotation text3 = new XYTextAnnotation(two, 70, 101.5);//“高血壓二期”
- //將上面的邊界線條，說明文字加入到xyplot中。
- xyplot.addAnnotation(box);
- xyplot.addAnnotation(box1);
- xyplot.addAnnotation(box2);
- xyplot.addAnnotation(box3);
- xyplot.addAnnotation(text);
- xyplot.addAnnotation(text1);
- xyplot.addAnnotation(text2);
- xyplot.addAnnotation(text3);
- // }
- return jfreechart;
- }
***一步，返回圖片URL
- public static void drawScatterChart(IrisIoInterface io, Log log,
- XYDataset xydataSet, String title, String shou, String shu,
- String nodata, String boolds, String nomal, String fore,
- String one, String two, List<PressureBean> list) {
- JFreeChart chart = createChart(xydataSet, title, shou, shu, nodata,
- boolds, nomal, fore, one, two, list, log);
- HttpServletRequest request = io.getRequest();
- String filename = "";
- String graphURL = "";
- try {
- filename = ServletUtilities.saveChartAsPNG(chart, 400, 300, null,
- io.getSession());
- graphURL = request.getContextPath() + "/displayChart?filename="
- + filename;
- } catch (IOException e) {
- // TODO Auto-generated catch block
- e.printStackTrace();
- log.error(e);
- }
- io.setData("filename", filename, BeanShare.BEAN_SHARE_REQUEST);
- io.setData("scatterurl", graphURL, BeanShare.BEAN_SHARE_REQUEST);
- }
效果圖：
原文鏈接：http://juliana-only.iteye.com/blog/544104
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責任編輯：林師授
來源：
遠去的渡口博客
