首先需要第三方的smartupload.jar包

（1）?????? 文件的上传

// 1.定义SmartLoad对象
		SmartUpload upload = new SmartUpload();
		upload.setCharset("utf-8");// 设置编码格式

		// 2.初始化upload
		upload.initialize(this.getServletConfig(), request, response);

		// 3.上传的配置
		upload.setMaxFileSize(1024 * 1024 * 1);// 设置文件大小
		upload.setTotalMaxFileSize(1024 * 1024 * 10); // 设置文件总的大小
		upload.setAllowedFilesList("jpg,gif");// 设置文件上传格式
		try {
			upload.setDeniedFilesList("bat,exe");// 设置不能上传的文件格式
		} catch (SQLException e) {
			e.printStackTrace();
		}

		// 4.获取request对象
		Request req = upload.getRequest();

		try {
			upload.upload();// 上传文件
			upload.save("/upload"); // 保存文件到根目录下(服务器下项目的根目录下)
		} catch (SmartUploadException e) {
			e.printStackTrace();
		}

		String filename = upload.getFiles().getFile(0).getFileName();// 获得上传的文件名

		//获得用户输入的参数信息
		String name = req.getParameter("name");
		double price = Double.parseDouble(req.getParameter("price"));
		int num = Integer.parseInt(req.getParameter("num"));
		String size = req.getParameter("size");
		String picture = filename;

		//实例化一个对象
		ClothBean cloth = new ClothBean(name, price, num, size, picture);

		ClothDAO clothDao = new ClothDAO();

		//添加衣服
		boolean b = clothDao.addCloth(cloth);

		if (b) {
			request.getRequestDispatcher("ShowClothServlet").forward(request,response);
		}

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（2）?????? 文件的下载

		// 下载服务器上的图片

		String filename = request.getParameter("filename");// 得到下载文件的名字

		// 创建一个实例
		SmartUpload upload = new SmartUpload();

		// 初始化
		upload.initialize(this.getServletConfig(), request, response);

		// 禁止浏览器打开文件
		upload.setContentDisposition(null);

		// 从服务器上下载文件
		try {
			upload.downloadFile("/upload/" + filename);
		} catch (SmartUploadException e) {
			e.printStackTrace();
		}

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