springboot-springmvc文件上传、下载、压缩打包

前言

最近负责了一个需求：每天定时拉取第三方报表数据，生成文件，并可以查看、下载、压缩打包。

遂单独记录下springmvc中文件的上传、下载和压缩打包这三个工作常用功能。

版本信息：

<springcloud.version>Greenwich.SR2</springcloud.version>
<springboot.version>2.1.7.RELEASE</springboot.version>
(<spring.version>5.1.9.RELEASE</spring.version>)

---

文件上传

• 单文件上传

//单文件上传
@RequestMapping("/upload")
@ResponseBody
public BaseResult upload(@RequestParam("file") MultipartFile file) {
	//文件信息获取
    String fileName = file.getOriginalFilename();
    long size = file.getSize()/1024; //单位 B>KB
    String contentType = file.getContentType();
    logger.info(">> file info to upload: {}, {}KB, {}", fileName, size, contentType);
    
    //目录生成与新文件名
    String newFileName = currDateStr.substring(8, currDateStr.length()) + "_" + fileName;
    String dateDir = currDateStr.substring(0, 8); //20191220
    File destDir = new File(upload_fspath_base, dateDir);// /xxx/upload/20191220
    if(!destDir.exists()) {
    	destDir.mkdirs(); //注意不是mkdir
    }
    
	//文件写入
	try {
		file.transferTo(new File(destDir, newFileName));
	} catch (IllegalStateException | IOException e) {
		logger.error("保存上传文件出错！", e);
		throw new BusinessException("保存上传文件出错！", e);
	}
	
	return BaseResult.succ();
}

• 多文件上传

//多文件上传
@RequestMapping("/uploads")
@ResponseBody
public BaseResult uploads(@RequestParam("files") MultipartFile[] files) {
	int succSize = Arrays.stream(files).map(this::upload).collect(Collectors.toList()).size();
	
	return BaseResult.succData(succSize);
}

• 注意：springboot预设的上传大小限制为10MB，对应配置项为

spring.servlet.multipart.max-file-size=200MB
spring.servlet.multipart.max-request-size=200MB

---

文件下载

• 方式1，使用 springmvc 的 ResponseEntity

//文件下载
@RequestMapping("/download/{code}")
public ResponseEntity<Resource> download(@PathVariable String code) { //上传下载码（唯一码）
	//查找上传记录
	UploadFileInfo fileInfo = uploadFileInfoRepo.findByUploadCode(code);
	
	if(Objects.nonNull(fileInfo)) {
		Resource resource = null;
		String contentType = null;
		try {
			//load file as Resource 
			if(!RichardUtil.isStrEmpty(fileInfo.getFsPath())) {
				resource = new FileSystemResource(new File(fileInfo.getFsPath()));
			}else {
				resource = new UrlResource(fileInfo.getSrcPath());
			}
			contentType = request.getServletContext().getMimeType(resource.getFile().getAbsolutePath());
		} catch (IOException e) {
			logger.error(code, e);
			throw new BusinessException("资源读取异常！", e);
		}
		if(Objects.isNull(contentType)) contentType = "application/octet-stream";
		
		return ResponseEntity.ok()
				.contentType(MediaType.parseMediaType(contentType))
				.header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename="" + fileInfo.getFileName() + """)
				.body(resource);
		
	}else {
		throw new BusinessException("资源未找到！");
	}
}

• 方式2，传统的 HttpServletResponse

见压缩示例一起

---

文件压缩/打包下载

• 意外发现使用传统的 response 更简洁好用，使用 springmvc 的 ResponseEntity 的话修改返回类型即可
• org.springframework.core.io.Resource 很好用
• 代码

/**
 * 文件（压缩打包）下载，传统response版
 */
@RequestMapping("/manage-api/download/zip5s")
@ResponseBody
public void zip5s() {
	List<UploadFileInfo> collect5 = uploadFileInfoRepo.findAll().stream().limit(5).collect(Collectors.toList());
	String showName = RichardUtil.getCurrentDatetimeStrNoFlag() + ".zip";
	//java7 资源自动关闭语法糖
	try(ZipOutputStream out = new ZipOutputStream(response.getOutputStream())){
		response.setHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename="" + showName + """);
		response.setContentType("application/octet-stream");
		for(UploadFileInfo o:collect5) {
			//load file resource
			Resource resource = RichardUtil.isStrEmpty(o.getFsPath())?new UrlResource(o.getSrcPath()):new FileSystemResource(o.getFsPath());
			//添加压缩
			out.putNextEntry(new ZipEntry(o.getFileName()));
			//写入（方法封装，目的流暂不关闭）
			RichardUtil.dump_dest_not_close(resource.getInputStream(), out);
		}
	} catch (IOException e) {
		logger.error(">> zip压缩打包异常", e);
		throw new BusinessException(e);
	}
}

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