/**
 * Configure the pipeline for TLS NPN negotiation to HTTP/2.
 */
private void configureSsl(SocketChannel ch) {
    ChannelPipeline pipeline = ch.pipeline();
    pipeline.addLast(sslCtx.newHandler(ch.alloc()));
    // We must wait for the handshake to finish and the protocol to be negotiated before configuring
    // the HTTP/2 components of the pipeline.
    pipeline.addLast(new ApplicationProtocolNegotiationHandler("") {
        @Override
        protected void configurePipeline(ChannelHandlerContext ctx, String protocol) {
            if (ApplicationProtocolNames.HTTP_2.equals(protocol)) {
                ChannelPipeline p = ctx.pipeline();
                p.addLast(connectionHandler);
                configureEndOfPipeline(p);
                return;
            }
            ctx.close();
            throw new IllegalStateException("unknown protocol: " + protocol);
        }
    });
}
 

/**
 * Configure the pipeline for TLS NPN negotiation to HTTP/2.
 */
private void configureSsl(SocketChannel ch) {
    ChannelPipeline pipeline = ch.pipeline();
    pipeline.addLast(sslCtx.newHandler(ch.alloc()));
    // We must wait for the handshake to finish and the protocol to be negotiated before configuring
    // the HTTP/2 components of the pipeline.
    pipeline.addLast(new ApplicationProtocolNegotiationHandler("") {
        @Override
        protected void configurePipeline(ChannelHandlerContext ctx, String protocol) {
            if (ApplicationProtocolNames.HTTP_2.equals(protocol)) {
                ChannelPipeline p = ctx.pipeline();
                p.addLast(connectionHandler);
                configureEndOfPipeline(p);
                return;
            }
            ctx.close();
            throw new IllegalStateException("unknown protocol: " + protocol);
        }
    });
}
 

/**
 * Configure the pipeline for TLS NPN negotiation to HTTP/2.
 */
private void configureSsl(SocketChannel ch) {
    SslContext sslCtx = SslContextBuilder.buildForClient();
    ChannelPipeline pipeline = ch.pipeline();
    pipeline.addLast(sslCtx.newHandler(ch.alloc()));
    // We must wait for the handshake to finish and the protocol to be negotiated
    // before configuring
    // the HTTP/2 components of the pipeline.
    pipeline.addLast(new ApplicationProtocolNegotiationHandler("") {
        @Override
        protected void configurePipeline(ChannelHandlerContext ctx, String protocol) {
            if (ApplicationProtocolNames.HTTP_2.equals(protocol)) {
                ChannelPipeline p = ctx.pipeline();
                p.addLast(connectionHandler);
                configureEndOfPipeline(p);
                return;
            }
            ctx.close();
            throw new IllegalStateException("unknown protocol: " + protocol);
        }
    });
}
 

public static ApplicationProtocolNegotiationHandler getServerAPNHandler() {
    ApplicationProtocolNegotiationHandler serverAPNHandler = new ApplicationProtocolNegotiationHandler(ApplicationProtocolNames.HTTP_2) {

        @Override
        protected void configurePipeline(ChannelHandlerContext ctx, String protocol) throws Exception {
            if (ApplicationProtocolNames.HTTP_2.equals(protocol)) {
                ctx.pipeline()
                    .addLast(Http2FrameCodecBuilder.forServer()
                        .build(), new Http2ServerResponseHandler());
                return;
            }
            throw new IllegalStateException("Protocol: " + protocol + " not supported");
        }
    };
    return serverAPNHandler;

}
 

/**
 * Configure the pipeline for TLS NPN negotiation to HTTP/2.
 */
private void configureSSL(SocketChannel ch) {
    final ChannelPipeline p = ch.pipeline();
    // 先通过 SSL/TLS 协商版本
    p.addLast(sslCtx.newHandler(ch.alloc()));
    // 根据版本加载不同的 ChannelHandler
    p.addLast(new ApplicationProtocolNegotiationHandler(ApplicationProtocolNames.HTTP_1_1) {
        @Override
        protected void configurePipeline(ChannelHandlerContext ctx, String protocol) throws Exception {
            if (ApplicationProtocolNames.HTTP_2.equals(protocol)) {
                ctx.pipeline().addLast(bizGroup, "Http2ChannelHandler",
                    new Http2ChannelHandlerBuilder(serverHandler).build());
                return;
            }

            if (ApplicationProtocolNames.HTTP_1_1.equals(protocol)) {
                ctx.pipeline().addLast("HttpServerCodec", new HttpServerCodec());
                ctx.pipeline().addLast("HttpObjectAggregator", new HttpObjectAggregator(maxHttpContentLength));
                ctx.pipeline().addLast(bizGroup, "Http1ChannelHandler",
                    new Http1ServerChannelHandler(serverHandler));
                return;
            }

            throw new IllegalStateException("unknown protocol: " + protocol);
        }
    });
}
 

public static ApplicationProtocolNegotiationHandler getClientAPNHandler(int maxContentLength, Http2SettingsHandler settingsHandler, Http2ClientResponseHandler responseHandler) {
    final Http2FrameLogger logger = new Http2FrameLogger(INFO, Http2Util.class);
    final Http2Connection connection = new DefaultHttp2Connection(false);

    HttpToHttp2ConnectionHandler connectionHandler = new HttpToHttp2ConnectionHandlerBuilder()
        .frameListener(new DelegatingDecompressorFrameListener(connection, new InboundHttp2ToHttpAdapterBuilder(connection).maxContentLength(maxContentLength)
        .propagateSettings(true)
        .build()))
        .frameLogger(logger)
        .connection(connection)
        .build();

    ApplicationProtocolNegotiationHandler clientAPNHandler = new ApplicationProtocolNegotiationHandler(ApplicationProtocolNames.HTTP_2) {
        @Override
        protected void configurePipeline(ChannelHandlerContext ctx, String protocol) {
            if (ApplicationProtocolNames.HTTP_2.equals(protocol)) {
                ChannelPipeline p = ctx.pipeline();
                p.addLast(connectionHandler);
                p.addLast(settingsHandler, responseHandler);
                return;
            }
            ctx.close();
            throw new IllegalStateException("Protocol: " + protocol + " not supported");
        }
    };

    return clientAPNHandler;

}