Question

但是，我想尽可能用GZIP压缩我的回复。我尝试在headfirst网站上免费下载Compression filter code。它适用于HTML，图像，CSS和JavaScript。

我接下来发布了过滤器。它检查GZIP是否为可接受的编码，并将gzip添加为Content-Encoding。请参阅：wrappedResp.setHeader("Content-Encoding", "gzip");

public class CompressionFilter implements Filter {

  private ServletContext ctx;
  private FilterConfig cfg;

    /**
     * The init method saves the config object and a quick reference to the
     * servlet context object (for logging purposes).
     */
  public void init(FilterConfig cfg) 
     throws ServletException {
    this.cfg = cfg;
    ctx = cfg.getServletContext();
    //ctx.log(cfg.getFilterName() + " initialized.");
  }

        /**
         * The heart of this filter wraps the response object with a Decorator
         * that wraps the output stream with a compression I/O stream.
         * Compression of the output stream is only performed if and only if
         * the client includes an Accept-Encoding header (specifically, for gzip).
         */
      public void doFilter(ServletRequest req,
                   ServletResponse resp,
                   FilterChain fc)
         throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) resp;

        // Dose the client accept GZIP compression?
        String valid_encodings = request.getHeader("Accept-Encoding");
        if ( (valid_encodings != null) && (valid_encodings.indexOf("gzip") > -1) ) {

          // Then wrap the response object with a compression wrapper
          // We'll look at this class in a minute.
          CompressionResponseWrapper wrappedResp = new CompressionResponseWrapper(response);

          // Declare that the response content is being GZIP encoded.
          wrappedResp.setHeader("Content-Encoding", "gzip");

          // Chain to the next component (thus processing the request)
          fc.doFilter(request, wrappedResp);

          // A GZIP compression stream must be "finished" which also
          // flushes the GZIP stream buffer which sends all of its
          // data to the original response stream.
          GZIPOutputStream gzos = wrappedResp.getGZIPOutputStream();
          gzos.finish();
          // The container handles the rest of the work.

          //ctx.log(cfg.getFilterName() + ": finished the request.");

        } else {
          fc.doFilter(request, response);
          //ctx.log(cfg.getFilterName() + ": no encoding performed.");
        }   
      }

      public void destroy() {
          // nulling out my instance variables
          cfg = null;
          ctx = null;
      }
    }

我正在使用下一个代码在Struts Web应用程序中发送JSON响应。

public ActionForward get(ActionMapping mapping,
    ActionForm     form,
    HttpServletRequest request,
    HttpServletResponse response) {
       JSONObject json = // Do some logic here
       RequestUtils.populateWithJSON(response, json);
       return null;         
}

public static void populateWithJSON(HttpServletResponse response,JSONObject json) {
    if(json!=null) {
        response.setContentType("text/x-json;charset=UTF-8");       
        response.setHeader("Cache-Control", "no-cache");
        try {
             response.getWriter().write(json.toString());
        } catch (IOException e) {
            throw new ApplicationException("IOException in populateWithJSON", e);
        }               
    }
 }

没有压缩它工作正常但如果我压缩JSON响应，我再也看不到我的JSON对象了。我使用JQuery处理带有代码片段的JSON Ajax调用，如下所示：

    $.post(url,parameters, function(json) {
    // Do some DOM manipulation with the data contained in the JSON Object
}, "json");

如果我看到Firebug的响应，它就是空的。

我应该折射我的压缩过滤器以跳过JSON响应中的压缩吗？或者有解决方法吗？

对我来说，看起来JQuery不能将响应识别为JSON，因为我正在添加Gzip压缩。

Answer 1

如果我看到Firebug的响应呢是空的。

有你的线索 - 它不是JQuery问题，它是服务器端。（我担心我无法帮助你，除了建议你不要再看客户端了）

gzipping ajax响应没有问题 - 如果你在Firebug中看不到响应，那么JQuery也看不到它。

Answer 2

如果要压缩它，则必须再添加一个标题“content-encoding：gzip”。

Answer 3

您是否尝试使用基于Java的显式客户端来确保jQuery或浏览器出现问题？如果java客户端出现故障，服务器响应就会出错。

但我猜测，虽然浏览器可以处理直接请求的解压缩，但这可能不适用于Ajax调用。

这是一个有趣的问题，我希望我们能得到一个更确定的答案。：）

使用GZIP，JSON响应和JQuery

3 个答案: