Netty心跳功能的实现

public class NettyClient {

	public static void main(String[] args) {
		
		ClientBootstrap bootstrap = new ClientBootstrap(new NioClientSocketChannelFactory(Executors.newCachedThreadPool(), 
				Executors.newCachedThreadPool()));
		
		Timer trigger=new HashedWheelTimer();  //注意
	    final ChannelHandler timeOutHandler=new ReadTimeoutHandler(trigger,60);//设置client读超时
	    final ChannelHandler idleStateHandler=new IdleStateHandler(trigger,60,5,0);  //设置读写超时写超时为60s,读超时为5s
		bootstrap.setPipelineFactory(new ChannelPipelineFactory() {  
            public ChannelPipeline getPipeline() throws Exception {  
            	ChannelPipeline pipeline = Channels.pipeline(); 
                 pipeline.addLast("decoder", new StringDecoder());
                 pipeline.addLast("encoder", new StringEncoder());
                 pipeline.addLast("timeOutHandler",timeOutHandler);
                 pipeline.addLast("idleStateHandler",idleStateHandler);
                 pipeline.addLast("SocketLinkState",new SocketLinkState());
                 pipeline.addLast("handler", new ClientHandler());
                return pipeline;
            }

            
        });  
		
		ChannelFuture future = bootstrap.connect(new InetSocketAddress("localhost", 8000));  
		  
        // Wait until the connection is closed or the connection attempt fails.  
        future.getChannel().getCloseFuture().awaitUninterruptibly();  
  
        // Shut down thread pools to exit.  
        bootstrap.releaseExternalResources();  

	}
}

SocketLinkState.java的实现
public class SocketLinkState extends IdleStateAwareChannelHandler {

	public void exceptionCaught(ChannelHandlerContext ctx,ExceptionEvent e) throws Exception{
		
	Throwable throwed=e.getCause();  
        throwed.printStackTrace();  
        if(throwed instanceof ReadTimeoutException){  
            ctx.getChannel().close();  
            
        }else if(throwed instanceof IOException){  
        	
            ctx.getChannel().close();  
        }else{
        	
        	super.exceptionCaught(ctx,e);  
        }
        
	}
	
	public void channelIdle(ChannelHandlerContext ctx,IdleStateEvent e) throws Exception{
		
		super.channelIdle(ctx,e);  
		Channel channel=e.getChannel();  
		
		switch(e.getState()){
		case READER_IDLE: {// 读取时间超时  
                // e.getChannel().close();// 关闭网络连接  
  
                // new RuntimeException().printStackTrace();  
		System.out.println("读取超时");
                    break;  
                  }  
		case WRITER_IDLE: {// 读取时间超时  
			 SocketHeartBeat.sendHeartBeat(channel);
			System.out.println("写超时");
                        break;  
                  }  
		}
	}
}
SocketHeartBeat.sendHeartBeat(channel) 的实现
public class SocketHeartBeat extends SimpleChannelHandler{

	public static void sendHeartBeat(Channel channel) {

		channel.write("abc");
	}

}

ClientHandler.java的实现
public class ClientHandler extends SimpleChannelHandler{
	
	 int i=0;
	 @Override  
     public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {  
         if (e.getMessage() instanceof String) {  
             String message = (String) e.getMessage();  
             System.out.println(message);  
             i++;
             Thread.sleep(7000);//我设置的写超时时间为5s，现在休眠7s，超时会发送心跳信息给server
             e.getChannel().write("xxxxxxx"+i); 
         }  

         super.messageReceived(ctx, e);  
     }  
	 
	 @Override  
     public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {  
         System.out.println("已经与Server建立连接。。。。");  
         System.out.println("\n请输入要发送的信息：");  
         super.channelConnected(ctx, e);  
         e.getChannel().write("server,我们连接了！！！");
         
         
     }

	 
}

NettyServer.java的实现
public class NettyServer {

	public static void main(String[] args) {
		ServerBootstrap bootstrap = new ServerBootstrap(new NioServerSocketChannelFactory(Executors.newCachedThreadPool(), 
				Executors.newCachedThreadPool())); 
		
		bootstrap.setPipelineFactory(new ChannelPipelineFactory() {  
            @Override  
            public ChannelPipeline getPipeline() throws Exception {  
                return Channels.pipeline(new StringDecoder(), new StringEncoder(), new ServerHandler());  
            }  
        });  
		
		Channel bind = bootstrap.bind(new InetSocketAddress(8000));  
        System.out.println("Server已经启动，监听端口: " + bind.getLocalAddress() + "， 等待客户端注册。。。"); 
	}
}

ServerHandler.java的实现
public class ServerHandler extends SimpleChannelHandler {

	public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {  
        if (e.getMessage() instanceof String) {  
            String message = (String) e.getMessage();  
            System.out.println("Client发来:" + message);  

            if("abc".equalsIgnoreCase(message)){
            	System.out.println("心跳。。。。。。。");
            }else{
            	e.getChannel().write("Server已收到刚发送的:" + message);  
            }
            
        }  

        super.messageReceived(ctx, e);  
    }  

	 public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) throws Exception {  
         super.exceptionCaught(ctx, e);  
     }  
	 
	 @Override  
     public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {  
         System.out.println("有一个客户端注册上来了。。。");  
         System.out.println("Client:" + e.getChannel().getRemoteAddress());  
         System.out.println("Server:" + e.getChannel().getLocalAddress());  
         System.out.println("\n等待客户端输入。。。");  
         super.channelConnected(ctx, e);  
     }  
}