Springboot/SpringMvc 读取上传 xls 文件内容

/**
 * 读取上传 xls 内容返回
 * @param file
 * @return
 */
@RequestMapping(value = "/read.xls")
@ResponseBody
public String read(@RequestParam("file") MultipartFile file) {
    //判断上传的文件类型是不是图片
    int maxSize = 1024 * 1024 * 2;
    if (file == null || file.getSize()> maxSize){
        object.put("msg","上传文件 不能为空/不能大于2M");
    }else{
        StringBuffer phones = new StringBuffer();
        try {
            Workbook wb = WorkbookFactory.create(file.getInputStream());
            Sheet sheet = wb.getSheetAt(0);// 第一个脚本下的
            logger.info(sheet.toString());
            sheet.forEach(e->{
                e.forEach(e1->{
                    e1.setCellType(Cell.CELL_TYPE_STRING);
                    phones.append(e1.getStringCellValue() + ",");
                });
            });
        } catch (Exception e) {
            e.printStackTrace();
        }
        if(phones.length()>0){
            phones.delete(phones.length()-1,phones.length());
        }
    }
    return phones.toString();
}