使用Apache POI 5.2.2创建Excel折线图

本教程将演示如何使用Apache POI 5.2.2库在Java中创建Excel折线图。我们将涵盖以下内容：

• 读取现有的Excel文件或创建一个新的Excel文件
• 添加数据到工作表
• 创建折线图
• 设置图表的标题和图例
• 自定义坐标轴（日期坐标轴、数值坐标轴）
• 添加多个数据系列
• 将数据系列关联到不同的坐标轴

代码示例

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellType;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xddf.usermodel.chart.*;
import org.apache.poi.xssf.usermodel.*;

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

public class ExcelChartExample {

    public static void main(String[] args) {
        try {
            // 读取Excel文件
            FileInputStream fileIn = new FileInputStream('input.xlsx');
            XSSFWorkbook workbook = new XSSFWorkbook(fileIn);
            XSSFSheet sheet1 = workbook.getSheet('Sheet1');

            // 创建折线图
            XSSFDrawing drawing = sheet1.createDrawingPatriarch();
            XSSFClientAnchor anchor = drawing.createAnchor(0, 0, 0, 0, 0, 12, 10, 22);
            XSSFChart 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.fromNumericCellRange(sheet1, new CellRangeAddress(1, 85, 1, 1));
            XDDFDateAxis bottomAxis = chart.createDateAxis(AxisPosition.BOTTOM);
            bottomAxis.setMajorTickMark(AxisTickMark.CROSS);
            bottomAxis.setMinorTickMark(AxisTickMark.NONE);
            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++) {
                XSSFRow row = sheet1.getRow(i + 1);
                if (row != null) {
                    Cell cell = row.getCell(1);
                    if (cell != null && cell.getCellType() == CellType.NUMERIC) {
                        Date date = cell.getDateCellValue();
                        String formattedDate = dateFormat.format(date);
                        bottomAxis.setTickLabelPosition(AxisTickLabelPosition.NEXT_TO);
                    }
                }
            }

            // 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> xs2 = XDDFDataSourcesFactory.fromNumericCellRange(sheet1, new CellRangeAddress(1, 127, 0, 0));
            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);

            // 添加第二个数据系列
            XDDFLineChartData.Series series2 = (XDDFLineChartData.Series) data.addSeries(xs2, ys2);
            series2.setTitle('折线图2', null);
            series2.setSmooth(false); // 取消平滑曲线

            // 将第二个数据系列关联到右侧坐标轴
            chart.plot(data);
            chart.getCTChart().getPlotArea().getLineChartArray(0).getSerArray(1).setAxId(1);

            // 保存Excel文件
            FileOutputStream fileOut = new FileOutputStream('output.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();
        }
    }
}

总结

本教程介绍了如何使用Apache POI 5.2.2在Java中创建Excel折线图。我们学习了如何添加数据系列、自定义坐标轴、设置图例以及将数据系列关联到不同的坐标轴。

希望本教程对您有所帮助！