HTTP協議上的GZIP編碼是一種用來改進WEB應用程序性能的技術。大流量的WEB站點常常使用GZIP壓縮技術來減少文件大小，減少文件大小有兩個明顯的好處，一是可以減少存儲空間，二是通過網絡傳輸文件時，可以減少傳輸的時間。

服務端有2種方式去壓縮，一種可以自己壓縮，但是更推薦第二種方式，用PrintWriter作為輸出流，工具類代碼如下

/**
         * 判斷瀏覽器是否支持 gzip 壓縮
         * @param req
         * @return boolean 值
         */
        public static boolean isGzipSupport(HttpServletRequest req) {
            String headEncoding = req.getHeader("accept-encoding");
            if (headEncoding == null || (headEncoding.indexOf("gzip") == -1)) { // 客戶端 不支持 gzip
                return false;
            } else { // 支持 gzip 壓縮
                return true;
            }
        }

        /**
         * 創建 以 gzip 格式 輸出的 PrintWriter 對象，如果瀏覽器不支持 gzip 格式，則創建普通的 PrintWriter 對象，
         * @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 壓縮
                pw = new PrintWriter(new GZIPOutputStream(resp.getOutputStream()));
                // 在 header 中設置返回類型為 gzip
                resp.setHeader("content-encoding", "gzip");
            } else { // // 客戶端 不支持 gzip
                pw = resp.getWriter();
            }
            return pw;
        }
    

 public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setCharacterEncoding("utf-8");
        response.setHeader("Content-Encoding", "gzip");
        String ret = "{\"ContentLayer\":{\"title\":\"內容層\"},\"PageLink\":{\"title\":\"頁面跳轉\"},\"WebBrowser\":{\"title\":\"瀏覽器\"},"
                + "\"InlinePage\":{\"title\":\"內嵌頁面\"},\"VideoComp\":{\"title\":\"視頻\"},"
                + "\"PopButton\":{\"title\":\"內容開關\"},\"ZoomingPic\":{\"title\":\"縮放大圖\"},"
                + "\"Rotate360\":{\"title\":\"360度旋轉\"}}";

        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);
    }

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{"ContentLayer":{"title":"內容層"},"PageLink":{"title":"頁面跳轉"},"WebBrowser":{"title":"瀏覽器"},"InlinePage":{"title":"內嵌頁面"},"VideoComp":{"title":"視頻"},"PopButton":{"title":"內容開關"},"ZoomingPic":{"title":"縮放大圖"},"Rotate360":{"title":"360度旋轉"}}

二.Android客戶端

得到HttpClient代碼：

private static DefaultHttpClient getHttpClient() {
        DefaultHttpClient httpClient = new DefaultHttpClient();

        // 設置 連接超時時間
        httpClient.getParams().setParameter(
                HttpConnectionParams.CONNECTION_TIMEOUT, TIMEOUT_CONNECTION);
        // 設置 讀數據超時時間
        httpClient.getParams().setParameter(HttpConnectionParams.SO_TIMEOUT,
                TIMEOUT_SOCKET);
        // 設置 字符集
        httpClient.getParams().setParameter("http.protocol.content-charset",
                UTF_8);
        return httpClient;
    }

private static HttpPost getHttpPost(String url) {
        HttpPost httpPost = new HttpPost(url);
        // 設置 請求超時時間
        httpPost.getParams().setParameter(HttpConnectionParams.SO_TIMEOUT,
                TIMEOUT_SOCKET);
        httpPost.setHeader("Connection", "Keep-Alive");
        httpPost.addHeader("Accept-Encoding", "gzip");
        return httpPost;
    }

public static InputStream http_post_return_byte(String url,
            Map<String, String> params) throws AppException {
        DefaultHttpClient httpclient = null;
        HttpPost post = null;
        HttpResponse response = null;
        StringBuilder sb = null;
        StringEntity stringEntity = null;
        try {
            httpclient = getHttpClient();
            post = getHttpPost(url);
            sb = new StringBuilder();
            if (params != null && !params.isEmpty()) {
                Logger.d("In http_post the url is get here");
                for (Entry<String, String> entry : params.entrySet()) {
                    sb.append(entry.getKey())
                            .append("=")
                            .append(URLEncoder.encode(entry.getValue(),
                                    HTTP.UTF_8)).append("&");
                }
                sb.deleteCharAt(sb.lastIndexOf("&"));
                Logger.d("In http_post the url is " + url + " and params is "
                        + sb.toString());
                stringEntity = new StringEntity(sb.toString());
                stringEntity
                        .setContentType("application/x-www-form-urlencoded");
                post.setEntity(stringEntity);
            }

            response = httpclient.execute(post);
            int statusCode = response.getStatusLine().getStatusCode();
            Logger.d("statusCode is " + statusCode);
            if (statusCode != HttpStatus.SC_OK) {
                throw AppException.http(statusCode);
            }

            InputStream is = response.getEntity().getContent();

            Header contentEncoding = response
                    .getFirstHeader("Content-Encoding");
            if (contentEncoding != null
                    && contentEncoding.getValue().equalsIgnoreCase("gzip")) {
                is = new GZIPInputStream(new BufferedInputStream(is));
            }
            return is;

        } catch (ClientProtocolException e) {
            e.printStackTrace();
            throw AppException.http(e);
        } catch (IOException e) {
            e.printStackTrace();
            throw AppException.network(e);
        } finally {

            /*
             * if (!post.isAborted()) {
             * 
             * post.abort(); } httpclient = null;
             */

        }

    }

來自：http://blog.csdn.net/shimiso/article/details/9033117