SpringBoot后台如何实现文件上传下载

1、单文件上传：

　

@RequestMapping(value = "/upload")
@ResponseBody
public String upload(@RequestParam("file") MultipartFile file) {
    try {
    if (file.isEmpty()) {
        return "文件为空";
    }
    // 获取文件名
    String fileName = file.getOriginalFilename();
    logger.info("上传的文件名为：" + fileName);
    // 获取文件的后缀名
    String suffixName = fileName.substring(fileName.lastIndexOf("."));
    logger.info("文件的后缀名为：" + suffixName);

    // 设置文件存储路径
    String filePath = "D://aim//";
    String path = filePath + fileName + suffixName;

    File dest = new File(path);
    // 检测是否存在目录
    if (!dest.getParentFile().exists()) {
        dest.getParentFile().mkdirs();// 新建文件夹
    }
    file.transferTo(dest);// 文件写入
    return "上传成功";
    } catch (IllegalStateException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return "上传失败";
}

　

2、多文件上传：

@RequestMapping(value = "/uploadMore", method = RequestMethod.POST)
@ResponseBody
public String handleFileUpload(HttpServletRequest request) {
    List<MultipartFile> files = ((MultipartHttpServletRequest) request).getFiles("file");
    MultipartFile file = null;
    BufferedOutputStream stream = null;
    for (int i = 0; i < files.size(); ++i) {
        file = files.get(i);
        String filePath = "D://aim//";
        if (!file.isEmpty()) {
            try {
                byte[] bytes = file.getBytes();
                stream = new BufferedOutputStream(new FileOutputStream(
                        new File(filePath + file.getOriginalFilename())));//设置文件路径及名字
                stream.write(bytes);// 写入
                stream.close();
            } catch (Exception e) {
                stream = null;
                return "第 " + i + " 个文件上传失败  ==> "
                        + e.getMessage();
            }
        } else {
            return "第 " + i
                    + " 个文件上传失败因为文件为空";
        }
    }
    return "上传成功";
}