Java 使用 Apache POI 库从 Excel 文件创建折线图

要实现你的要求，你可以使用 Apache POI 库来读取 Excel 文件并生成折线图。以下是一个示例代码，可以帮助你开始：

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.*;

public class ExcelLineChartExample {
    public static void main(String[] args) {
        String filePath = 'input-1.xlsx';
        String sheetName = 'P1';
        
        try {
            // 读取 Excel 文件
            FileInputStream file = new FileInputStream(filePath);
            Workbook workbook = new XSSFWorkbook(file);
            Sheet sheet = workbook.getSheet(sheetName);
            
            // 创建折线图
            Drawing drawing = sheet.createDrawingPatriarch();
            ClientAnchor anchor = drawing.createAnchor(0, 0, 0, 0, 0, 5, 10, 15);
            Chart chart = drawing.createChart(anchor);
            ChartLegend legend = chart.getOrCreateLegend();
            legend.setPosition(LegendPosition.BOTTOM);
            
            LineChartData data = chart.getChartDataFactory().createLineChartData();
            
            // 设置横坐标轴
            ChartAxis bottomAxis = chart.getChartAxisFactory().createCategoryAxis(AxisPosition.BOTTOM);
            bottomAxis.setTitle('时间');
            bottomAxis.setCrosses(AxisCrosses.AUTO_ZERO);
            
            // 设置纵坐标轴
            ValueAxis leftAxis = chart.getChartAxisFactory().createValueAxis(AxisPosition.LEFT);
            leftAxis.setTitle('数值');
            leftAxis.setCrosses(AxisCrosses.AUTO_ZERO);
            
            // 读取数据并添加到折线图中
            Row row = sheet.getRow(0);
            for (int i = 0; i < 127; i++) {
                Cell xCell = row.getCell(i);
                Cell yCell = sheet.getRow(2).getCell(i);
                double xValue = xCell.getNumericCellValue();
                double yValue = yCell.getNumericCellValue();
                
                data.addSeries(
                    chart.getChartAxisFactory().createCategoryAxis(AxisPosition.BOTTOM),
                    chart.getChartAxisFactory().createValueAxis(AxisPosition.LEFT),
                    chart.getChartDataFactory().createCategoryDataSource(sheet, new CellRangeAddress(0, 0, i, i)),
                    chart.getChartDataFactory().createNumericDataSource(sheet, new CellRangeAddress(2, 2, i, i))
                );
            }
            
            chart.plot(data, bottomAxis, leftAxis);
            
            // 保存 Excel 文件
            FileOutputStream outFile = new FileOutputStream(filePath);
            workbook.write(outFile);
            outFile.close();
            
            System.out.println('折线图已生成并保存在 P1 工作表中。');
            
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

请确保你已经将 Apache POI 库添加到你的项目依赖中。这段代码会读取名为 'input-1.xlsx' 的 Excel 文件中的 'P1' 工作表，并根据你的要求生成折线图，然后将结果保存回原始文件。