Spring Boot中Excel数据导入导出的高效实现

import org.apache.poi.ss.usermodel.*;
import org.springframework.web.multipart.MultipartFile;
 
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
 
public class ExcelService {
 
    public List<String[]> readExcel(MultipartFile file) throws Exception {
        InputStream in = file.getInputStream();
        Workbook workbook = WorkbookFactory.create(in);
        Sheet sheet = workbook.getSheetAt(0);
        List<String[]> data = new ArrayList<>();
 
        for (Row row : sheet) {
            int columnCount = row.getLastCellNum();
            String[] rowData = new String[columnCount];
            for (int cn=0; cn<columnCount; cn++) {
                Cell cell = row.getCell(cn, Row.MissingCellPolicy.RETURN_BLANK_AS_NULL);
                rowData[cn] = (cell == null) ? "" : cell.toString();
            }
            data.add(rowData);
        }
 
        workbook.close();
        return data;
    }
 
    public Workbook writeExcel(List<String[]> data) {
        Workbook workbook = new XSSFWorkbook();
        Sheet sheet = workbook.createSheet();
        int rowNum = 0;
 
        for (String[] rowData : data) {
            Row row = sheet.createRow(rowNum++);
            int columnNum = 0;
            for (String cellData : rowData) {
                Cell cell = row.createCell(columnNum++);
                cell.setCellValue(cellData);
            }
        }
 
        return workbook;
    }
}

这个简化版的代码示例展示了如何在Spring Boot应用中读取和写入Excel数据。readExcel方法接收一个MultipartFile实例，并返回一个字符串数组列表，每个数组代表一个Excel行的数据。writeExcel方法接收一个数据列表，并创建一个新的Excel工作簿。这个示例省略了异常处理和资源清理的代码，但在实际应用中应该加以处理。