简单文件上传与下载

上传

配置文件

spring:
  servlet:
    multipart:
      max-file-size: 300MB
      max-request-size: 300MB

前端代码

<!-- class不用管！！！ -->
<form action="/admin/upload" method="post" enctype="multipart/form-data" class="ui form">
    <div class="required field">
        <div class="ui left labeled input">
            <input type="file" name="file">
        </div>
    </div>
    <div class="ui right aligned container">
        <button class="ui teal submit button">提交</button>
        <button type="button" class="ui button" onclick="window.history.go(-1)">返回</button>
    </div>
</form>

后端代码

@Controller
public class UploadController {

    //上传后文件保存位置
    @Value("static/files")
    private String fileLocation;

    @PostMapping("/admin/upload")
    public String upload(MultipartFile file, Model model) throws IOException {
        System.out.println("进入upload");
        // 获得 classpath 的绝对路径
        String realPath = ResourceUtils.getURL("classpath:").getPath() + fileLocation;
        File newFile = new File(realPath);
        // 如果文件夹不存在、则新建
        if (!newFile.exists()){
            newFile.mkdirs();
        }
        // 上传
        Date date = new Date();
        String fileName = date.getTime() +"@" + file.getOriginalFilename();
        file.transferTo(new File(newFile, fileName));
        return "admin/upload";
    }
}

示例

下载

后端

@Controller
public class UploadController {

    @Value("static/files")
    private String fileLocation;

    @GetMapping("/admin/download")
    public void download(String fileName, HttpServletResponse response) throws IOException {
        System.out.println("download");
        // 获得待下载文件所在文件夹的绝对路径
        String realPath = ResourceUtils.getURL("classpath:").getPath() + fileLocation;
        
        // 获得文件输入流
        FileInputStream inputStream = new FileInputStream(new File(realPath, fileName));
        // 设置响应头、以附件形式打开文件
        response.setHeader("content-disposition", "attachment; fileName=" + fileName);
        ServletOutputStream outputStream = response.getOutputStream();
        int len = 0;
        byte[] data = new byte[1024];
        while ((len = inputStream.read(data)) != -1) {
            outputStream.write(data, 0, len);
        }
        outputStream.close();
        inputStream.close();
    }
}