spring-boot 文件上传下载

1.文件上传配置

spring:
  servlet:
    multipart:
      max-file-size: 20MB
      max-request-size: 10MB

2.前端写法

  <form action="URL" method="post" enctype="multipart/form-data">
        <input type="file" name="file">
        <button type="submit">上传</button>
    </form>

3.后端实现单文件上传

     /**
     * 实现文件上传
     * */
    @RequestMapping("fileUpload")
    @ResponseBody 
    public String fileUpload(@RequestParam("fileName") MultipartFile file){
        if(file.isEmpty()){
            return "false";
        }
        String fileName = file.getOriginalFilename();
        int size = (int) file.getSize();
        
        String path = "C:/test" ;
        File dest = new File(path + "/" + fileName);
        if(!dest.getParentFile().exists()){ //判断文件父目录是否存在
            dest.getParentFile().mkdir();
        }
        try {
            file.transferTo(dest); //保存文件
            return "true";
        } catch (IllegalStateException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return "false";
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return "false";
        }
    }

4.后端实现多文件上传

/**
     * 实现多文件上传
     * */
    @RequestMapping(value="multifileUpload",method=RequestMethod.POST) 
　　/**public @ResponseBody String multifileUpload(@RequestParam("fileName")List<MultipartFile> files) */
    public @ResponseBody String multifileUpload(HttpServletRequest request){
        
        List<MultipartFile> files = ((MultipartHttpServletRequest)request).getFiles("fileName");
        
        if(files.isEmpty()){
            return "false";
        }

        String path = "F:/test" ;
        
        for(MultipartFile file:files){
            String fileName = file.getOriginalFilename();
            int size = (int) file.getSize();
            System.out.println(fileName + "-->" + size);
            
            if(file.isEmpty()){
                return "false";
            }else{        
                File dest = new File(path + "/" + fileName);
                if(!dest.getParentFile().exists()){ //判断文件父目录是否存在
                    dest.getParentFile().mkdir();
                }
                try {
                    file.transferTo(dest);
                }catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                    return "false";
                } 
            }
        }
        return "true";
    }
}

5.后端实现文件下载

@RequestMapping("/download")
    public String downLoad(HttpServletResponse response) throws UnsupportedEncodingException {
        String filename="2.xlsx";
        String filePath = "D:/download" ;
        File file = new File(filePath + "/" + filename);
        if(file.exists()){ //判断文件父目录是否存在
            response.setContentType("application/vnd.ms-excel;charset=UTF-8");
            response.setCharacterEncoding("UTF-8");
           // response.setContentType("application/force-download");
            response.setHeader("Content-Disposition", "attachment;fileName=" +   java.net.URLEncoder.encode(filename,"UTF-8"));
            byte[] buffer = new byte[1024];
            FileInputStream fis = null; //文件输入流
            BufferedInputStream bis = null;

            OutputStream os = null; //输出流
            try {
                os = response.getOutputStream();
                fis = new FileInputStream(file);
                bis = new BufferedInputStream(fis);
                int i = bis.read(buffer);
                while(i != -1){
                    os.write(buffer);
                    i = bis.read(buffer);
                }

            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            System.out.println("----------file download---" + filename);
            try {
                bis.close();
                fis.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return null;
    }