错误：此数据集已包含键对象为1的序列

Question

背景：我正在添加x

问题：然而，我在将序列添加到我的XYSeriesCollection中时遇到了困难。所以我创建了一个名为序列1的XYSeries，并将两个值添加到其中。然后当我将该序列1数据添加到XYSeriesCollection时，它会抛出：“此数据集已经包含具有键Object 1的序列”错误。

问题：这个错误意味着什么，我如何解决它？

代码：

    private void renderChartBtnActionPerformed(java.awt.event.ActionEvent evt) {                                               

        String manufacturer = "";
        
        XYSeriesCollection dcd = new XYSeriesCollection();
        
        String[] splitLine = new String[4];
        String[][] twoD_arr = new String[arraySize][4];
        int kount = 0;
        double dnum = 0;
        double dnum2 = 0;
        
         // Checks which radio button is selected and sets equal to manufacturer
        if (audiRB.isSelected()) {
            manufacturer = "Audi";
        }
        else if (volvoRB.isSelected()) {
            manufacturer = "Volvo";       
        }
        
        Iterator<String> itr = carData.iterator();
        while(itr.hasNext()){
            splitLine = itr.next().split(",");
            for(int i=0;i<=3;i++){
                twoD_arr[kount][i] = splitLine[i];
               
            }
            kount = kount + 1;
        }
        // Checks which data type is selected and adds data to series
        for(int i=0; i< twoD_arr.length; i++){
            if (pctShare.isSelected() && (twoD_arr[i][1]).equals(manufacturer)) {
                XYSeries series1 = new XYSeries("Object 1");
                                
                dnum = Double.parseDouble(twoD_arr[i][3]);
                dnum2 = Double.parseDouble(twoD_arr[i][0]);
                series1.add(dnum, dnum2);
                System.out.println(dnum);
                System.out.println(dnum2);
                dcd.addSeries(series1);
            } 
            else if (qtySold.isSelected() && (twoD_arr[i][1]).equals(manufacturer)) {
//                inum = Integer.parseInt(twoD_arr[i][2]);
//                dcd.setValue(inum, "Quantity Sold", twoD_arr[i][0]);
//                dcd.setValue(dnum, dnum, dnum);
//                System.out.println(twoD_arr[i][0] + twoD_arr[i][2]);
                     
            }                
        }
        
         // User selection of chart type        
         if( LineRB.isSelected()){
            jchart = ChartFactory.createXYLineChart("New Car Sales in Norway", "Date", manufacturer, dcd);
        }
        else if(AreaRB.isSelected()){
            jchart = ChartFactory.createXYAreaChart("New Car Sales in Norway", "Date", manufacturer, dcd, PlotOrientation.VERTICAL, true, true, false);
        }
        else if(barRB.isSelected()){
            jchart = ChartFactory.createXYStepAreaChart("New Car Sales in Norway", "Date", manufacturer, dcd, PlotOrientation.VERTICAL, true, true, false);       
        }
        else {
           jchart = null; 
        }
        
        // Add chart to panel
        ChartPanel chartPanel = new ChartPanel(jchart);
        inner_chart_pnl.removeAll();
        inner_chart_pnl.add(chartPanel);
        inner_chart_pnl.updateUI(); 

    }      

Answer 1

XYSeriesCollection根据给定给每个序列的可比较键区分它包含的序列。在您的示例中，该键是String，Object 1。向序列添加数据的循环每次都会尝试通过循环构造和添加序列。相反，在循环之前创建序列，添加数据，然后在填充后添加完整的序列：

XYSeries series1 = new XYSeries("Object 1");
for(int i=0; i< twoD_arr.length; i++) {
    //XYSeries series1 = new XYSeries("Object 1");
    …
    //dcd.addSeries(series1);
} 
dcd.addSeries(series1);

这里显示了一个完整的示例。