GZip传输数据

一.服务端

服务端有2种方式去压缩，一种可以自己压缩，但是更推荐第二种方式，用PrintWriter作为输出流，工具类代码如下：

                /**
		 * 判断浏览器是否支持 gzip 压缩
		 * @param req
		 * @return boolean 值
		 */
		public static boolean isGzipSupport(HttpServletRequest req) {
			String headEncoding = req.getHeader("accept-encoding");
			if (headEncoding == null || (headEncoding.indexOf("gzip") == -1)) { // 客户端 不支持 gzip
				return false;
			} else { // 支持 gzip 压缩
				return true;
			}
		}

		/**
		 * 创建 以 gzip 格式 输出的 PrintWriter 对象，如果浏览器不支持 gzip 格式，则创建普通的 PrintWriter 对象，
		 * @param req
		 * @param resp
		 * @return
		 * @throws IOException
		 */
		public static PrintWriter createGzipPw(HttpServletRequest req, HttpServletResponse resp) throws IOException {
			PrintWriter pw = null;
			if (isGzipSupport(req)) { // 支持 gzip 压缩
				pw = new PrintWriter(new GZIPOutputStream(resp.getOutputStream()));
				// 在 header 中设置返回类型为 gzip
				resp.setHeader("content-encoding", "gzip");
			} else { // // 客户端 不支持 gzip
				pw = resp.getWriter();
			}
			return pw;
		}
	

servlet代码如下：

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setCharacterEncoding("utf-8");
		response.setHeader("Content-Encoding", "gzip");
		String ret = "{\"ContentLayer\":{\"title\":\"内容层\"},\"PageLink\":{\"title\":\"页面跳转\"},\"WebBrowser\":{\"title\":\"浏览器\"},"
				+ "\"InlinePage\":{\"title\":\"内嵌页面\"},\"VideoComp\":{\"title\":\"视频\"},"
				+ "\"PopButton\":{\"title\":\"内容开关\"},\"ZoomingPic\":{\"title\":\"缩放大图\"},"
				+ "\"Rotate360\":{\"title\":\"360度旋转\"}}";
		
		PrintWriter pw = new PrintWriter(new GZIPOutputStream(response.getOutputStream()));
		pw.write(ret);
		pw.close();
	}

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		this.doPost(request, response);
	}

在代理软件中跟踪到的数据如下：

‹«VrÎÏ+IÍ+ñI¬L-R²ªV*É,ÉIU²R:rëÄÝM•ju”ÓS}2ó²‘e/m>üì̏ë«@òá©INEùåŨúŸ¬?pàØw¼g^Nf^*ÈTóo™R–™’šïœŸ[€¬àÔåc[ÁÖç8•–”äç¡»nÿª7@
¢òós3óÒ2“‘Uœþºýè–Ïg÷€Tå—$–¤› +r·¸ðä‡Zh¤†ˆ

实际数据如下：

{"ContentLayer":{"title":"内容层"},"PageLink":{"title":"页面跳转"},"WebBrowser":{"title":"浏览器"},"InlinePage":{"title":"内嵌页面"},"VideoComp":{"title":"视频"},"PopButton":{"title":"内容开关"},"ZoomingPic":{"title":"缩放大图"},"Rotate360":{"title":"360度旋转"}}

二. iOS客户端

利用ASIHttpRequest的功能

创建 request

    NSString* urlStr=@"http://localhost:8080/servlet/userInfo";//test servlet
    urlStr=[urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];//Support Chinese
    NSURL *url = [NSURL URLWithString:urlStr];
    ASIHTTPRequest* request =[ASIHTTPRequest requestWithURL:url];
    request.delegate=self;

    [request setAllowCompressedResponse:YES];//default is YES. Support gzip stream data
    [request startAsynchronous];

回调成功函数

    BOOL s = [request isResponseCompressed];//is Response add "GZip" format to header
    
   // NSData *uncompressedData = [request rawResponseData]; // 未压缩后的数据
    NSData *uncompressedData = [request responseData]; // 解压缩后的数据
    NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
    if(request.responseStatusCode==200){
        NSString *dataString = [[NSString alloc]initWithData:uncompressedData encoding:enc];//convert to normal NSString
        NSLog(@"%@",dataString);
    ｝