Java Excel 时间日期数据间隔插入 - Apache POI 实现

可以使用 Apache POI 库来读取和写入 Excel 文件。下面是一个示例代码，可以实现你的需求：

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

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;

public class DateInsertion {
    public static void main(String[] args) {
        String inputFile = 'input.xlsx';
        String outputFile = 'output.xlsx';
        String sheetName = 'P1';

        try {
            FileInputStream fis = new FileInputStream(inputFile);
            Workbook workbook = new XSSFWorkbook(fis);
            Sheet sheet = workbook.getSheet(sheetName);

            List<Date> dates = getDates(sheet);

            boolean hasGapGreaterThan10Days = true;
            while (hasGapGreaterThan10Days) {
                hasGapGreaterThan10Days = false;
                List<Date> newDates = new ArrayList<>();

                for (int i = 0; i < dates.size() - 1; i++) {
                    Date current = dates.get(i);
                    Date next = dates.get(i + 1);
                    long diffInDays = getDifferenceInDays(current, next);

                    if (diffInDays > 10) {
                        hasGapGreaterThan10Days = true;
                        newDates.add(current);
                        newDates.addAll(getIntermediateDates(current, next));
                    } else {
                        newDates.add(current);
                    }
                }

                newDates.add(dates.get(dates.size() - 1));
                dates = newDates;
            }

            updateSheet(sheet, dates);
            FileOutputStream fos = new FileOutputStream(outputFile);
            workbook.write(fos);
            workbook.close();
            fos.close();

            System.out.println('Dates insertion completed successfully.');
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static List<Date> getDates(Sheet sheet) {
        List<Date> dates = new ArrayList<>();

        for (Row row : sheet) {
            Cell cell = row.getCell(0);
            if (cell != null && cell.getCellType() == CellType.NUMERIC) {
                Date date = cell.getDateCellValue();
                dates.add(date);
            }
        }

        return dates;
    }

    private static long getDifferenceInDays(Date date1, Date date2) {
        long diffInMs = Math.abs(date2.getTime() - date1.getTime());
        return diffInMs / (24 * 60 * 60 * 1000);
    }

    private static List<Date> getIntermediateDates(Date start, Date end) {
        List<Date> intermediateDates = new ArrayList<>();
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(start);
        calendar.add(Calendar.DAY_OF_MONTH, 1);

        while (calendar.getTime().before(end)) {
            intermediateDates.add(calendar.getTime());
            calendar.add(Calendar.DAY_OF_MONTH, 1);
        }

        return intermediateDates;
    }

    private static void updateSheet(Sheet sheet, List<Date> dates) {
        int rowIndex = 0;
        for (Date date : dates) {
            Row row = sheet.getRow(rowIndex);
            if (row == null) {
                row = sheet.createRow(rowIndex);
            }
            Cell cell = row.getCell(0);
            if (cell == null) {
                cell = row.createCell(0);
            }
            cell.setCellValue(date);
            rowIndex++;
        }
    }
}

请确保将 input.xlsx 替换为你的输入文件的路径，并将 output.xlsx 替换为你想要保存结果的文件路径。另外，请确保你的 Excel 文件中 P1 工作表的日期数据位于第一列。

这段代码会读取输入文件中的日期数据，然后根据你的要求进行插入操作，直到每个相邻的日期间隔小于 10 天。最后，它会将结果写入到输出文件中。