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Java文件上传与下载压缩

发布时间 2023-09-06 16:44:54作者: ProsperousEnding

文件上传与下载压缩

文件上传:

这是一个通用的本地文件的上传代码,可以将文件类型存储到相应的本地目录下
注:本次演示为存储路径为项目所在的resources目录下,可通过url去访问本地文件数据适用于图片文本等的图片上传组件

    // 保存的路径，相对路径，此处为项目resources目录下位置
    private String relativePath = "src/main/resources";

@PostMapping(value = "/upload")
@Transactional
@ResponseBody
public void upload(@RequestParam("file") MultipartFile file, HttpServletRequest request) throws IOException {
   if (ObjectUtil.isNull(file) || StrUtil.isBlank(filename)) {
        throw new ResponseStatusException(HttpStatus.NOT_FOUND, "文件或文件名为空");
    }

//1.创建文件夹
    // 获取resource目录下路径
      File directory = new File(relativePath);
    //自定义路径
    String uploadPath = directory.getCanonicalPath()+ "/static/upload/";
     File uploadFolder = new File(uploadPath);
        if (!uploadFolder.exists()) {
            uploadFolder.mkdirs();
        }

//2.保存文件
   String filename = file.getOriginalFilename();
   //添加随机的UUID,文件重命名
    String rename = filename.substring(0, filename.lastIndexOf(".")) + "_" + RandomUtil.randomString(16);
    //文件后缀
    String suffix = filename.substring(filename.lastIndexOf(".") + 1);
    //完整文件名
    String longName = rename +"."+ suffix;

    file.transferTo(new File(uploadFolder, longName));
     //浏览器访问该静态资源路径
    String urlPath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + "/upload/"  + longName;
        
//3.存储附件表
    Attachments att = new Attachments();
        att.setFileName(longName);
        att.setPath("/upload/"+longName);
        att.setUrlPath(urlPath);
    attachementsMapper.insert(att);
    }

文件下载并添加到zip中进行下载

   @GetMapping(value = "/downloadZip")
    @Transactional
    public void downloadZip(HttpServletResponse response, HttpServletRequest request) throws IOException {

//1. 设置响应头
        response.setCharacterEncoding("utf-8");
        response.setContentType("application/oct-stream");
        // 返回客户端浏览器的版本号、类型
        String agent = request.getHeader("USER-AGENT");
        // 设置压缩包的名字，date为时间戳
        Instant now = Instant.now();
        long timestamp = now.toEpochMilli();
        String time = String.valueOf(timestamp);
        String downloadName = time + ".zip";
        try {
            // 针对IE或者以IE为内核的浏览器：
            if (agent.contains("MSIE") || agent.contains("Trident")) {
                downloadName = URLEncoder.encode(downloadName, StandardCharsets.UTF_8);
            } else {
                // 非IE浏览器的处理：
                downloadName = new String(downloadName.getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1);
            }
        } catch (Exception e) {
            throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, "系统异常");
        }
        final String charset = ObjectUtil.defaultIfNull(response.getCharacterEncoding(), CharsetUtil.UTF_8);
        response.setHeader("Content-Disposition", StrUtil.format("attachment;filename=\"{}\"",
                URLUtil.encode(downloadName, CharsetUtil.charset(charset))));

//2.取得文件列表
        List<Attachments> attachmentList=Lists.newArrayListWithCapacity(10);
        
//3.遍历压缩 
        // 设置压缩流：直接写入response，实现边压缩边下载(@Cleanup用法类似于try-catch异常并主动关闭流)
        @Cleanup OutputStream outputStream = response.getOutputStream();
        @Cleanup ZipOutputStream zipOs = new ZipOutputStream(outputStream);
        // 设置压缩方法
        zipOs.setMethod(ZipOutputStream.DEFLATED);
        // 遍历文件信息（主要获取文件名/文件路径等）
        for (Attachments a : attachmentList) {
            String filename = a.getFileName();
            String contextPath = "/upload/" + f.getFileName();
            File file = new File(contextPath);
            Assert.isTrue(file.exists(), "文件不存在");
            zipOs.putNextEntry(new ZipEntry(filename));
            @Cleanup FileInputStream fs = new FileInputStream(file);
            IOUtils.copy(fs, zipOs);
        }
    }