【开发指南】Spring Cloud集成POI完成Excel读写操作

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.io.InputStream;
 
public class ExcelUtil {
 
    public static Workbook readExcel(String filePath) throws IOException {
        InputStream is = new FileInputStream(filePath);
        Workbook workbook = new XSSFWorkbook(is);
        return workbook;
    }
 
    public static void writeExcel(Workbook workbook, String filePath) throws IOException {
        FileOutputStream fos = new FileOutputStream(filePath);
        workbook.write(fos);
        fos.close();
    }
 
    public static void main(String[] args) {
        try {
            Workbook workbook = readExcel("example.xlsx");
            Sheet sheet = workbook.getSheetAt(0);
            Row row = sheet.getRow(0);
            if (row == null) {
                row = sheet.createRow(0);
            }
            Cell cell = row.getCell(0);
            if (cell == null) {
                cell = row.createCell(0);
            }
            cell.setCellValue("新值");
            writeExcel(workbook, "example_modified.xlsx");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

这段代码展示了如何使用Apache POI库来读取和写入Excel文件。readExcel方法用于打开一个Excel文件并返回一个Workbook对象。writeExcel方法用于将Workbook对象写入到一个文件中。在main方法中，我们读取了一个名为example.xlsx的Excel文件，修改了第一行第一列的值，并将修改后的Workbook写入到了一个新的文件example_modified.xlsx中。