如何实现excel的导入导出请给出代码

以下是Java代码实现Excel的导入导出：

Excel导入：

public List<List<String>> readExcel(String filePath) throws Exception {
    List<List<String>> result = new ArrayList<>();
    Workbook workbook = null;
    try {
        workbook = WorkbookFactory.create(new File(filePath));
        Sheet sheet = workbook.getSheetAt(0);
        for (int i = sheet.getFirstRowNum(); i <= sheet.getLastRowNum(); i++) {
            Row row = sheet.getRow(i);
            if (row == null) {
                continue;
            }
            List<String> rowList = new ArrayList<>();
            for (int j = row.getFirstCellNum(); j <= row.getLastCellNum(); j++) {
                Cell cell = row.getCell(j);
                if (cell == null) {
                    continue;
                }
                rowList.add(cell.toString());
            }
            result.add(rowList);
        }
    } finally {
        if (workbook != null) {
            workbook.close();
        }
    }
    return result;
}

Excel导出：

public void writeExcel(String filePath, List<List<String>> data) throws Exception {
    Workbook workbook = new XSSFWorkbook();
    Sheet sheet = workbook.createSheet();
    for (int i = 0; i < data.size(); i++) {
        Row row = sheet.createRow(i);
        List<String> rowList = data.get(i);
        for (int j = 0; j < rowList.size(); j++) {
            Cell cell = row.createCell(j);
            cell.setCellValue(rowList.get(j));
        }
    }
    FileOutputStream outputStream = null;
    try {
        outputStream = new FileOutputStream(filePath);
        workbook.write(outputStream);
    } finally {
        if (outputStream != null) {
            outputStream.close();
        }
        if (workbook != null) {
            workbook.close();
        }
    }
}

需要注意的是，需要引入Apache POI库才能使用以上代码。