MINA无法回调messageReceived函数

最新推荐文章于 2023-05-03 12:32:29 发布

ruyi366

最新推荐文章于 2023-05-03 12:32:29 发布

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分类专栏： Android 文章标签： MINA Android

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本文是在Android客户端上与服务器建立长连接，固定时间端发送心跳包。但发送初始化消息后，一直不能回调IoHandlerAdapter的messageReceived函数，虽然已经打印了接收Log（RECEIVED: HeapBuffer[...]）。

本文基于：mina-core-2.0.16.jar和slf4j-android-1.6.1-RC1.jar，主要代码如下：

......
connector = new NioSocketConnector();
connector.setConnectTimeoutMillis(PushConstant.CONNECT_TIMEOUT);

// 设置日志输出工厂
connector.getFilterChain().addLast("logger", new LoggingFilter());
// 设置请求和响应对象的编解码操作
connector.getFilterChain().addLast("codec", new ProtocolCodecFilter(new ByteArrayCodecFactory()));
// 创建心跳工厂
ClientKeepAliveMessageFactory heartBeatFactory = new ClientKeepAliveMessageFactory();
// 当读操作空闲时发送心跳
KeepAliveFilter heartBeat = new KeepAliveFilter(heartBeatFactory, IdleStatus.READER_IDLE);
// 设置是否将事件继续往下传递
heartBeat.setForwardEvent(true);
// 设置心跳包请求后超时无反馈情况下的处理机制，默认为关闭连接,在此处设置为输出日志提醒
heartBeat.setRequestTimeoutHandler(KeepAliveRequestTimeoutHandler.LOG);
//设置心跳频率
heartBeat.setRequestInterval(180);
connector.getFilterChain().addLast("keepAlive", heartBeat);

// 设置接收和发送缓冲区大小
connector.getSessionConfig().setReceiveBufferSize(1024);
connector.getSessionConfig().setSendBufferSize(1024);
// 设置读取空闲时间：单位为s
connector.getSessionConfig().setReaderIdleTime(180);

// 设置长连接业务逻辑处理类Handler
LongConnectHandler longConnectHandler = new LongConnectHandler();
connector.setHandler(longConnectHandler);

......
......

private class LongConnectHandler extends IoHandlerAdapter {
 
        @Override
        public void sessionCreated(IoSession session) throws Exception {
            super.sessionCreated(session);
        }


        @Override
        public void sessionClosed(IoSession session) throws Exception {
            super.sessionClosed(session);
        }

        @Override
        public void exceptionCaught(IoSession session, Throwable cause) throws Exception {
            super.exceptionCaught(session, cause);
        }

        @Override
        public void messageReceived(IoSession session, Object message) throws Exception {
            System.err.println("接受消息成功...");
            super.messageReceived(session, message);
        }

        @Override
        public void messageSent(IoSession session, Object message) throws Exception {
            super.messageSent(session, message);
        }
}

ClientKeepAliveMessageFactory类实现如下：

private class ClientKeepAliveMessageFactory implements KeepAliveMessageFactory {


        @Override
        public boolean isRequest(IoSession ioSession, Object o) {
            return false;
        }

        @Override
        public boolean isResponse(IoSession ioSession, Object o) {
            return false;
        }

        @Override
        public Object getRequest(IoSession ioSession) {
            try {
                return IoBuffer.wrap(heartBeat().bytes());
            } catch (IOException e) {
                e.printStackTrace();
                return null;
            }
        }

        @Override
        public Object getResponse(IoSession ioSession, Object o) {
            return null;
        }
    }

搜到网上说是编解码错误，导致没有回调，但单步调试并没有发现错误。后来将ClientKeepAliveMessageFactory的isResponse的返回值从true改成了false，回调居然正常了，查看KeepAliveFilter.java源码：

    @Override
    public void messageReceived(NextFilter nextFilter, IoSession session, Object message) throws Exception {
        try {
            if (messageFactory.isRequest(session, message)) {
                Object pongMessage = messageFactory.getResponse(session, message);

                if (pongMessage != null) {
                    nextFilter.filterWrite(session, new DefaultWriteRequest(pongMessage));
                }
            }

            if (messageFactory.isResponse(session, message)) {
                resetStatus(session);
            }
        } finally {
            if (!isKeepAliveMessage(session, message)) {
                nextFilter.messageReceived(session, message);
            }
        }
    }
	
	
    private boolean isKeepAliveMessage(IoSession session, Object message) {
        return messageFactory.isRequest(session, message) || messageFactory.isResponse(session, message);
    }

从源码可知，只有不是KeepAlive消息时，才将回调下一个Filter的messageReceived函数。

参考文献：

1、http://bbs.youkuaiyun.com/topics/390173203

2、https://my.oschina.net/yjwxh/blog/174633

3、http://blog.youkuaiyun.com/kkk0526/article/details/51732437