java下载

// 支持在线打开文件的一种方式
	public static void downLoad(String filePath, HttpServletResponse response,HttpServletRequest request,
			boolean isOnLine) throws Exception {
		File file = new File(filePath);
		if (!file.exists()) {
			response.sendError(404, " File not found! ");
			return;
		}
		BufferedInputStream br = new BufferedInputStream(new FileInputStream(file));
		byte[] buf = new byte[1024];
		int len = 0;

		response.reset(); // 非常重要
		if (isOnLine) { // 在线打开方式
			URL u = new URL(" file:/// " + filePath);
			response.setContentType(u.openConnection().getContentType());
			response.setHeader(" Content-Disposition ", " inline; filename= "
					+ URLEncoder.encode(file.getName(),"utf-8"));
			// 文件名应该编码成UTF-8
		} else { // 纯下载方式
			ServletContext application = request.getSession().getServletContext();
			String mimetype=null;
			mimetype = application.getMimeType(filePath);
			if (mimetype == null) {
				mimetype = "application/octet-stream;charset=ISO8859-1";
			}
			response.setContentType(mimetype);
			String ua = request.getHeader("User-Agent"); // 返回客户端浏览器的版本号、类型
			if (ua == null)
				ua = "User-Agent: Mozilla/4.0 (compatible; MSIE 6.0;)";
			boolean isIE = ua.toLowerCase().indexOf("msie") != -1; // 是否为 IE
			if (isIE && !isOnLine) {
				mimetype = "application/x-msdownload";
			}
			// 下面我们将设法让客户端保存文件的时候显示正确的文件名, 具体就是将文件名
			// 转换为 ISO8859-1 编码
//			String downFileName = new String(file.getName().getBytes(), "ISO8859-1");

			String inlineType = isOnLine ? "inline" : " attachment"; // 是否内联附件
			response.setHeader("Content-Disposition", inlineType + ";filename=\""
					+ URLEncoder.encode(file.getName(),"utf-8") + "\"");
			response.setContentType(" application/x-msdownload ");
//			response.setHeader(" Content-Disposition ",
//					" attachment; filename= " +URLEncoder.encode(file.getName(),"utf-8") );
		}
		OutputStream out = response.getOutputStream();
		while ((len = br.read(buf)) > 0)
			out.write(buf, 0, len);
		br.close();
		out.close();
	}