Question

我正在尝试编写一个使用HTTP保持连接的HTTP客户端。当我从ClientBoostrap连接时，我得到了频道。我可以重复使用它来发送多个HTTP请求吗？是否有任何示例证明HTTP Keep Alive功能？

我还有另一个问题。现在我的客户端工作没有保持连接。我正在调用ClientHandler的messageReceived方法中的channel.close。但似乎连接没有关闭，一段时间后套接字耗尽，我得到了BindException。任何指针都会非常感激。

由于

Answer 1

只要Connection头没有设置为CLOSE（可能HttpVersion是1.1，虽然不确定），但代码行类似于此......

request.setHeader(HttpHeaders.Names.CONNECTION, HttpHeaders.Values.CLOSE);

...您的频道应该对多个请求/响应对保持打开状态。

这是我今天为测试它而编写的一些示例代码。您可以在关闭频道之前退出Google的任意数量的请求：

 public class TestHttpClient {
    static class HttpResponseReader extends SimpleChannelUpstreamHandler {
        int remainingRequests = 2;

        @Override
        public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
            HttpResponse response = (HttpResponse) e.getMessage();

            System.out.println("Beginning -------------------");
            System.out.println(new String(response.getContent().slice(0, 50).array()));
            System.out.println("End -------------------\n");

            if(remainingRequests-- > 0)
                sendRequest(ctx.getChannel());
            else
                ctx.getChannel().close();
        }
    }

    public static void main(String[] args) {
        ClientBootstrap bootstrap = new ClientBootstrap(new NioClientSocketChannelFactory());
        bootstrap.setPipeline(Channels.pipeline(
                new HttpClientCodec(),
                new HttpResponseReader()));
        // bootstrap.setOption("child.keepAlive", true); // no apparent effect

        ChannelFuture future = bootstrap.connect(new InetSocketAddress("google.com", 80));
        Channel channel = future.awaitUninterruptibly().getChannel();

        channel.getCloseFuture().addListener(new ChannelFutureListener() {
            public void operationComplete(ChannelFuture future) throws Exception {
                // this winds up getting called immediately after the receipt of the first message by HttpResponseReader!
                System.out.println("Channel closed");
            }
        });

        sendRequest(channel);

        while(true) {
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    private static void sendRequest(Channel channel) {
        // Prepare the HTTP request.
        HttpRequest request = new DefaultHttpRequest(
                HttpVersion.HTTP_1_1, HttpMethod.GET, "http://www.google.com");
        request.setHeader(HttpHeaders.Names.HOST, "google.com");
        request.setHeader(HttpHeaders.Names.ACCEPT_ENCODING, HttpHeaders.Values.GZIP);

        channel.write(request);
    }
}

如何使用Netty处理Http Keep-Alive连接

1 个答案: