poi 导出Excel 折线图 线是虚线

您可以使用POI库来导出Excel折线图，并且可以设置线条为虚线。下面是一个示例代码，展示了如何使用POI来实现这个功能：

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.*;

import java.io.FileOutputStream;
import java.io.IOException;

public class ExcelChartExample {
    public static void main(String[] args) {
        // 创建一个新的Excel工作簿
        Workbook workbook = new XSSFWorkbook();
        Sheet sheet = workbook.createSheet("折线图示例");

        // 创建一个数据源
        Row row1 = sheet.createRow(0);
        row1.createCell(0).setCellValue(1);
        row1.createCell(1).setCellValue(2);
        row1.createCell(2).setCellValue(3);
        row1.createCell(3).setCellValue(4);

        Row row2 = sheet.createRow(1);
        row2.createCell(0).setCellValue(5);
        row2.createCell(1).setCellValue(6);
        row2.createCell(2).setCellValue(7);
        row2.createCell(3).setCellValue(8);

        // 创建一个折线图
        Drawing drawing = sheet.createDrawingPatriarch();
        ClientAnchor anchor = drawing.createAnchor(0, 0, 0, 0, 4, 0, 10, 20);
        Chart chart = drawing.createChart(anchor);

        ChartLegend legend = chart.getOrCreateLegend();
        legend.setPosition(LegendPosition.BOTTOM);

        LineChartData data = chart.getChartDataFactory().createLineChartData();

        // 创建折线
        ChartAxis bottomAxis = chart.getChartAxisFactory().createCategoryAxis(AxisPosition.BOTTOM);
        ValueAxis leftAxis = chart.getChartAxisFactory().createValueAxis(AxisPosition.LEFT);
        leftAxis.setCrosses(AxisCrosses.AUTO_ZERO);

        ChartDataSource<Number> xs = DataSources.fromNumericCellRange(sheet, new CellRangeAddress(0, 0, 0, 3));
        ChartDataSource<Number> ys1 = DataSources.fromNumericCellRange(sheet, new CellRangeAddress(1, 1, 0, 3));
        ChartDataSource<Number> ys2 = DataSources.fromNumericCellRange(sheet, new CellRangeAddress(2, 2, 0, 3));

        LineChartSeries series1 = data.addSeries(xs, ys1);
        series1.setTitle(sheet.getRow(1).getCell(0).getStringCellValue());

        LineChartSeries series2 = data.addSeries(xs, ys2);
        series2.setTitle(sheet.getRow(2).getCell(0).getStringCellValue());

        // 设置线条样式为虚线
        CTChartLines lines1 = series1.getCTLineSer().addNewSpPr().addNewLn().addNewPr();
        lines1.addNewDash().setVal(new byte[]{4, 4});

        CTChartLines lines2 = series2.getCTLineSer().addNewSpPr().addNewLn().addNewPr();
        lines2.addNewDash().setVal(new byte[]{4, 4});

        // 将图表添加到工作表
        chart.plot(data, bottomAxis, leftAxis);

        // 保存Excel文件
        try {
            FileOutputStream fileOut = new FileOutputStream("折线图示例.xlsx");
            workbook.write(fileOut);
            fileOut.close();
            workbook.close();
            System.out.println("Excel文件导出成功！");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

这个示例代码会创建一个包含折线图的Excel文件，并且将线条样式设置为虚线。您可以根据需要修改数据源和线条样式的设置。请确保将POI库添加到项目的依赖中。