public void processRequest(GetRequest request, Socket socket) throws IOException, ProxyCacheException {
        OutputStream out = new BufferedOutputStream(socket.getOutputStream());
        String responseHeaders = newResponseHeaders(request);
        out.write(responseHeaders.getBytes("UTF-8"));

        long offset = request.rangeOffset;
        if (isUseCache(request)) {
            responseWithCache(out, offset);
        } else {
            responseWithoutCache(out, offset);
        }
    }
{@link ProxyCache} that read http url and writes data to {@link Socket}
VideoCache/src/main/java/com/yc/videocache/HttpProxyCache.java