poi excel content-Type设置

在使用POI操作Excel文件时，可以通过设置Content-Type来指定生成的Excel文件的类型。具体步骤如下：

1. 导入相关包

import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import javax.servlet.http.HttpServletResponse;
import java.io.OutputStream;

2. 在Controller中设置Content-Type

@RequestMapping("/downloadExcel")
public void downloadExcel(HttpServletResponse response) {
    try {
        //创建Workbook对象
        Workbook workbook = new XSSFWorkbook();
        //Workbook workbook = new HSSFWorkbook();

        //设置Content-Type
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        //response.setContentType("application/vnd.ms-excel");

        //设置文件名
        response.setHeader("Content-Disposition", "attachment;filename=test.xlsx");
        //response.setHeader("Content-Disposition", "attachment;filename=test.xls");

        //将Workbook写入OutputStream
        OutputStream outputStream = response.getOutputStream();
        workbook.write(outputStream);
        outputStream.flush();
        outputStream.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

其中，Content-Type分别为application/vnd.openxmlformats-officedocument.spreadsheetml.sheet和application/vnd.ms-excel，分别对应xlsx和xls格式的Excel文件。

需要注意的是，在使用XSSFWorkbook时，Content-Type应该设置为application/vnd.openxmlformats-officedocument.spreadsheetml.sheet；在使用HSSFWorkbook时，Content-Type应该设置为application/vnd.ms-excel。