Java POI Excel 折线图生成示例 - 使用 Apache POI 库绘制数据趋势

import org.apache.poi.ss.usermodel.Cell; import org.apache.poi.ss.usermodel.CellType; import org.apache.poi.ss.usermodel.Row; import org.apache.poi.ss.util.CellRangeAddress; import org.apache.poi.xddf.usermodel.chart.*; import org.apache.poi.xssf.usermodel.XSSFClientAnchor; import org.apache.poi.xssf.usermodel.XSSFDrawing; import org.apache.poi.xssf.usermodel.XSSFSheet; import org.apache.poi.xssf.usermodel.XSSFWorkbook; import org.openxmlformats.schemas.drawingml.x2006.chart.CTLineSer;

import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.text.SimpleDateFormat; import java.util.Date;

public class ExcelChartExample04 {

public static void main(String[] args) {
    try {
        // 读取Excel文件
        FileInputStream fileIn = new FileInputStream('input-1.xlsx');
        XSSFWorkbook workbook = new XSSFWorkbook(fileIn);
        XSSFSheet sheet1 = workbook.getSheet('P1');

        // 创建折线图
        XSSFDrawing drawing = sheet1.createDrawingPatriarch();
        XSSFClientAnchor anchor = drawing.createAnchor(0, 0, 0, 0, 0, 129, 10, 149);
        XDDFChart chart = drawing.createChart(anchor);
        chart.setTitleText('数据折线图');
        chart.setTitleOverlay(false);

        // 设置图例位置
        XDDFChartLegend legend = chart.getOrAddLegend();
        legend.setPosition(LegendPosition.BOTTOM);

        // 设置横坐标轴为日期坐标轴
        XDDFDataSource<?> dateSource = XDDFDataSourcesFactory.fromArray(new String[] {'A2:A127'});
        XDDFDateAxis bottomAxis = chart.createDateAxis(AxisPosition.BOTTOM);
        bottomAxis.setCrosses(AxisCrosses.AUTO_ZERO);
        bottomAxis.setTitle('时间');
        bottomAxis.setTickLabelPosition(AxisTickLabelPosition.NEXT_TO);

        // 设置时间格式
        SimpleDateFormat dateFormat = new SimpleDateFormat('yyyy/MM/dd');
        for (int i = 0; i < dateSource.getPointCount(); i++) {
            Row row = sheet1.getRow(i + 1);
            if (row != null) {
                Cell cell = row.getCell(0);
                if (cell != null && cell.getCellType() == CellType.NUMERIC) {
                    Date date = cell.getDateCellValue();
                    String formattedDate = dateFormat.format(date);
                    cell.setCellValue(formattedDate);
                }
            }
        }

        // 设置左侧坐标轴为温度坐标轴
        XDDFValueAxis leftAxis = chart.createValueAxis(AxisPosition.LEFT);
        leftAxis.setCrosses(AxisCrosses.AUTO_ZERO);
        leftAxis.setTitle('温度');

        // 设置右侧坐标轴为数值坐标轴
        XDDFValueAxis rightAxis = chart.createValueAxis(AxisPosition.RIGHT);
        rightAxis.setCrosses(AxisCrosses.MAX);
        rightAxis.setTitle('数据值');

        // 设置数据源
        XDDFNumericalDataSource<Double> xs1 = XDDFDataSourcesFactory.fromNumericCellRange(sheet1, new CellRangeAddress(1, 127, 0, 0));
        XDDFNumericalDataSource<Double> ys1 = XDDFDataSourcesFactory.fromNumericCellRange(sheet1, new CellRangeAddress(1, 127, 1, 1));
        XDDFNumericalDataSource<Double> ys2 = XDDFDataSourcesFactory.fromNumericCellRange(sheet1, new CellRangeAddress(1, 127, 2, 2));

        // 添加数据系列
        XDDFLineChartData data = (XDDFLineChartData) chart.createData(ChartTypes.LINE, bottomAxis, leftAxis);
        XDDFLineChartData.Series series1 = (XDDFLineChartData.Series) data.addSeries(xs1, ys1);
        series1.setTitle('折线图1', null);
        series1.setSmooth(false);
        series1.setMarkerStyle(MarkerStyle.NONE);

        // 添加第二个数据系列
        XDDFLineChartData.Series series2 = (XDDFLineChartData.Series) data.addSeries(xs1, ys2);
        series2.setTitle('折线图2', null);
        series2.setSmooth(false);
        chart.getCTChart().getPlotArea().getLineChartArray(0).getSerArray(1).getOrder().setVal(1);

        // 设置次要垂直坐标轴
        CTLineSer ctLineSer = chart.getCTChart().getPlotArea().getLineChartArray(0).getSerArray(1);
        ctLineSer.addNewDLbls();
        ctLineSer.getDLbls().addNewShowLegendKey().setVal(false);
        ctLineSer.getDLbls().addNewShowVal().setVal(false);
        ctLineSer.getDLbls().addNewShowCatName().setVal(false);
        ctLineSer.getDLbls().addNewShowSerName().setVal(false);

        // 保存Excel文件
        FileOutputStream fileOut = new FileOutputStream('input-1.xlsx');
        workbook.write(fileOut);
        fileOut.close();

        System.out.println('折线图已创建并保存到Excel文件中。');

    } catch (IOException e) {
        e.printStackTrace();
    }
}

}

// 解决办法：

在创建折线图之前，需要先在Excel文件中添加数据。你可以在代码中找到以下部分：

// 设置数据源
XDDFNumericalDataSource<Double> xs1 = XDDFDataSourcesFactory.fromNumericCellRange(sheet1, new CellRangeAddress(1, 127, 0, 0));
XDDFNumericalDataSource<Double> ys1 = XDDFDataSourcesFactory.fromNumericCellRange(sheet1, new CellRangeAddress(1, 127, 1, 1));
XDDFNumericalDataSource<Double> ys2 = XDDFDataSourcesFactory.fromNumericCellRange(sheet1, new CellRangeAddress(1, 127, 2, 2));

这部分代码指定了折线图的数据源范围。你需要确保在这个范围内存在有效的数据。你可以根据你的实际需求修改这个范围。

另外，你还需要确保Excel文件中存在名为“P1”的工作表。如果你的Excel文件中没有这个工作表，你需要修改以下代码：

XSSFSheet sheet1 = workbook.getSheet('P1');

将“P1”修改为你实际的工作表名称。

完成以上修改后，再次运行程序，应该能够正确创建折线图并保存到Excel文件中。