怎么用springboot实现excel导出

您可以使用POI库来实现SpringBoot中的Excel导出功能。首先需要在pom.xml文件中添加以下依赖：

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>4.1.2</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>4.1.2</version>
</dependency>

然后可以创建一个ExcelUtils类来实现Excel导出功能。以下是一个示例代码：

public class ExcelUtils {
  public static void exportExcel(HttpServletResponse response, List<?> dataList, String fileName, String sheetName) {
    XSSFWorkbook workbook = new XSSFWorkbook();
    XSSFSheet sheet = workbook.createSheet(sheetName);
    XSSFRow row;
    XSSFCell cell;
    int rowNum = 0;
    row = sheet.createRow(rowNum++);

    // 添加表头
    List<String> headers = Arrays.asList("ID", "Name", "Age");
    for (int i = 0; i < headers.size(); i++) {
      cell = row.createCell(i);
      cell.setCellValue(headers.get(i));
    }

    // 往Excel表格中添加数据
    for (Object data : dataList) {
      row = sheet.createRow(rowNum++);
      // 获取data的属性值
      int id = BeanUtils.getProperty(data, "id");
      String name = BeanUtils.getProperty(data, "name");
      int age = BeanUtils.getProperty(data, "age");
      row.createCell(0).setCellValue(id);
      row.createCell(1).setCellValue(name);
      row.createCell(2).setCellValue(age);
    }

    // 设置响应头
    response.setContentType("application/vnd.ms-excel");
    response.setHeader("Content-Disposition", "attachment;filename=" + fileName);
    OutputStream outputStream;
    try {
      outputStream = response.getOutputStream();
      workbook.write(outputStream);
      outputStream.flush();
      outputStream.close();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

您可以在任何SpringBoot的Controller中使用ExcelUtils类来导出Excel。例如，以下是一个基于HTTP GET请求的Controller：

@GetMapping("/exportExcel")
public void exportExcel(HttpServletResponse response) {
  List<User> userList = userService.getAllUsers();
  ExcelUtils.exportExcel(response, userList, "User List", "Sheet1");
}