JFreeChart时间序列图绘制

JFreeChartExample.java

//关于乱码解决，将相应的字体文件拷贝到$JAVA_HOME/jre/lib/fonts/fallback文件夹下即可
static private Font font = new Font("宋体", Font.PLAIN, 12);    
public byte[] jFreeChartExample(String day) {
        try {
            Date end = DateUtils.parseDate(day, TableHelper.YYYY_MM_DD);
            Date start = DateUtils.addDays(end, -29);

            TimeSeriesCollection collTransfer = new TimeSeriesCollection();
            TimeSeriesCollection collWaitTime = new TimeSeriesCollection();
            TimeSeries seriesTransfer = new TimeSeries("平均转接次数");
            TimeSeries seriesWaitTime = new TimeSeries("平均等待时间(s)");
             
            //数据来源省略
            collTransfer.addSeries(seriesTransfer);

            collWaitTime.addSeries(seriesWaitTime);

            JFreeChart jFreeChart = ChartFactory.createTimeSeriesChart(
                    cityMap.get(cityId) + DateFormatUtils.format(start, "yyyy.MM.dd") + "-" + DateFormatUtils.format(end, "yyyy.MM.dd") + " 生态400服务质量趋势图",// 图表标题
                    "", // 主轴标签（x轴）
                    "",// 范围轴标签（y轴）
                    collWaitTime, // 数据集
                    true, // 是否包含图例
                    true, // 提示信息是否显示
                    false);// 是否使用urls
            setCharts(jFreeChart);

            XYPlot xyPlot = jFreeChart.getXYPlot();
            setXYPlot(xyPlot);

            //设置第二个y轴
            NumberAxis numberAxis1 = new NumberAxis("");
            numberAxis1.setNumberFormatOverride(new DecimalFormat("#.###"));
            xyPlot.setRangeAxis(1, numberAxis1);
            xyPlot.setDataset(1, collTransfer);
            xyPlot.mapDatasetToRangeAxis(1, 1);

            //第一个y轴的renderer
            XYItemRenderer renderer = xyPlot.getRenderer();
            renderer.setBaseToolTipGenerator(StandardXYToolTipGenerator.getTimeSeriesInstance());

            //第二个y轴的renderer
            xyPlot.setRenderer(1, new StandardXYItemRenderer());

            //第一个y轴精度
            NumberAxis numberAxis = (NumberAxis) xyPlot.getRangeAxis();
            numberAxis.setNumberFormatOverride(new DecimalFormat("#.#"));

            logger.info("title:{}, legend:{}", jFreeChart.getTitle().getFont(), jFreeChart.getLegend().getItemFont());
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
            ChartUtilities.writeChartAsJPEG(outputStream, 1, jFreeChart, 1000, 400);
            return outputStream.toByteArray();
        } catch (ParseException | IOException e) {
            e.printStackTrace();
        }
        return new byte[0];
    }

private void setCharts(JFreeChart jFreeChart) {
        jFreeChart.getTitle().setFont(font);
        RectangleInsets insets = new RectangleInsets(5, 5, 5, 5);
        LegendTitle legend = jFreeChart.getLegend();
        if (legend != null) {
            legend.setMargin(insets);
            legend.setItemFont(font);
        }
        jFreeChart.setPadding(insets);
        jFreeChart.setBackgroundPaint(Color.WHITE);
    }

    private void setXYPlot(XYPlot xyPlot) {
        xyPlot.setBackgroundPaint(Color.WHITE);
        xyPlot.setRangeGridlinesVisible(true);
        xyPlot.setDomainGridlinesVisible(true);
        xyPlot.setDomainZeroBaselineVisible(false);
        xyPlot.setRangeZeroBaselineVisible(false);
        xyPlot.setRangeGridlinePaint(Color.GRAY);
        xyPlot.setDomainGridlinePaint(Color.GRAY);

        DateAxis dateaxis = (DateAxis) xyPlot.getDomainAxis();
        dateaxis.setDateFormatOverride(new SimpleDateFormat(TableHelper.YYYY_MM_DD));
        dateaxis.setTickUnit(new DateTickUnit(DateTickUnitType.DAY, 3));//x 轴刻度间隔为 3
    }