Netty学习06--Netty心跳

绝地灬酷狼 2023-02-17 12:28 227阅读 0赞

netty入门教程话题之心跳

1、学习idleStateHandler

用来检测会话状态

2、心跳其实就是一个普通的请求，特点数据简单，业务也简单  
心跳对于服务端来说，定时清除闲置会话inactive(netty5) channelclose(netty3)  
心跳对客户端来说，用来检测会话是否断开，是否重连！ 用来检测网络延时！

1.netty3的心跳实现。

![20200614100939931.png][]

HelloHandler

package com.cxb.netty3.heart;
    
    import org.jboss.netty.channel.ChannelEvent;
    import org.jboss.netty.channel.ChannelFuture;
    import org.jboss.netty.channel.ChannelFutureListener;
    import org.jboss.netty.channel.ChannelHandlerContext;
    import org.jboss.netty.channel.MessageEvent;
    import org.jboss.netty.channel.SimpleChannelHandler;
    import org.jboss.netty.handler.timeout.IdleState;
    import org.jboss.netty.handler.timeout.IdleStateEvent;
    
    public class HelloHandler extends SimpleChannelHandler {
    
    	@Override
    	public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
    		System.out.println(e.getMessage());
    	}
    
    	@Override
    	public void handleUpstream(final ChannelHandlerContext ctx, ChannelEvent e) throws Exception {
    		if (e instanceof IdleStateEvent) {
    			if(((IdleStateEvent)e).getState() == IdleState.ALL_IDLE){
    				System.out.println("踢玩家下线");
    				//关闭会话,踢玩家下线
    				ChannelFuture write = ctx.getChannel().write("time out, you will close");
    				write.addListener(new ChannelFutureListener() {
    					@Override
    					public void operationComplete(ChannelFuture future) throws Exception {
    						 ctx.getChannel().close();
    					}
    				});
    			}
    		} else {
    			super.handleUpstream(ctx, e);
    		}
    	}
    
    }

Server

package com.cxb.netty3.heart;
    
    import java.net.InetSocketAddress;
    import java.util.concurrent.ExecutorService;
    import java.util.concurrent.Executors;
    
    import org.jboss.netty.bootstrap.ServerBootstrap;
    import org.jboss.netty.channel.ChannelPipeline;
    import org.jboss.netty.channel.ChannelPipelineFactory;
    import org.jboss.netty.channel.Channels;
    import org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory;
    import org.jboss.netty.handler.codec.string.StringDecoder;
    import org.jboss.netty.handler.codec.string.StringEncoder;
    import org.jboss.netty.handler.timeout.IdleStateHandler;
    import org.jboss.netty.util.HashedWheelTimer;
    /**
     * netty服务端入门
     */
    public class Server {
    
    	public static void main(String[] args) {
    
    		//服务类
    		ServerBootstrap bootstrap = new ServerBootstrap();
    		
    		//boss线程监听端口，worker线程负责数据读写
    		ExecutorService boss = Executors.newCachedThreadPool();
    		ExecutorService worker = Executors.newCachedThreadPool();
    		
    		//设置niosocket工厂
    		bootstrap.setFactory(new NioServerSocketChannelFactory(boss, worker));
    		
    		final HashedWheelTimer hashedWheelTimer = new HashedWheelTimer();
    		//设置管道的工厂
    		bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
    			
    			@Override
    			public ChannelPipeline getPipeline() throws Exception {
    
    				ChannelPipeline pipeline = Channels.pipeline();
    				// 这里设置超时时间10s，期间内没有操作，则会关闭
    				pipeline.addLast("idle", new IdleStateHandler(hashedWheelTimer, 5, 5, 10));
    				pipeline.addLast("decoder", new StringDecoder());
    				pipeline.addLast("encoder", new StringEncoder());
    				pipeline.addLast("helloHandler", new HelloHandler());
    				return pipeline;
    			}
    		});
    		
    		bootstrap.bind(new InetSocketAddress(8007));
    		
    		System.out.println("start!");
    		
    	}
    
    }

测试，使用telnet连接测试，等待10s，如果没有操作，则关闭连接。

![2020061410112199.png][]

![20200614101112727.png][]

发送了消息之后，10内不超过也会断开连接。

![20200614101218846.png][]

2.netty5的心跳实现

![2020061410131456.png][]

ServerHandler

package com.cxb.netty5.heart;
    
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelFutureListener;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.SimpleChannelInboundHandler;
    import io.netty.handler.timeout.IdleState;
    import io.netty.handler.timeout.IdleStateEvent;
    /**
     * 服务端消息处理
     */
    public class ServerHandler extends SimpleChannelInboundHandler<String> {
    
    	@Override
    	protected void messageReceived(ChannelHandlerContext ctx, String msg) throws Exception {
    
    		System.out.println(msg);
    		
    		ctx.channel().writeAndFlush("hi");
    		ctx.writeAndFlush("hi");
    	}
    	
    	
    
    	@Override
    	public void userEventTriggered(final ChannelHandlerContext ctx, Object evt) throws Exception {
    		if(evt instanceof IdleStateEvent){
    			IdleStateEvent event = (IdleStateEvent)evt;
    			if(event.state() == IdleState.ALL_IDLE){
    				//清除超时会话
    				ChannelFuture writeAndFlush = ctx.writeAndFlush("time is gone, you will close");
    				writeAndFlush.addListener(new ChannelFutureListener() {
    					
    					@Override
    					public void operationComplete(ChannelFuture future) throws Exception {
    						ctx.channel().close();
    					}
    				});
    			}
    		}else{
    			super.userEventTriggered(ctx, evt);
    		}
    	}
    
    
    	/**
    	 * 新客户端接入
    	 */
    	@Override
    	public void channelActive(ChannelHandlerContext ctx) throws Exception {
    		System.out.println("channelActive");
    	}
    
    	/**
    	 * 客户端断开
    	 */
    	@Override
    	public void channelInactive(ChannelHandlerContext ctx) throws Exception {
    		System.out.println("channelInactive");
    	}
    
    	/**
    	 * 异常
    	 */
    	@Override
    	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
    		cause.printStackTrace();
    	}
    	
    	
    }

Server

package com.cxb.netty5.heart;
    
    import io.netty.bootstrap.ServerBootstrap;
    import io.netty.channel.Channel;
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelInitializer;
    import io.netty.channel.ChannelOption;
    import io.netty.channel.EventLoopGroup;
    import io.netty.channel.nio.NioEventLoopGroup;
    import io.netty.channel.socket.nio.NioServerSocketChannel;
    import io.netty.handler.codec.string.StringDecoder;
    import io.netty.handler.codec.string.StringEncoder;
    import io.netty.handler.timeout.IdleStateHandler;
    
    /**
     * netty5服务端
     */
    public class Server {
    
    	public static void main(String[] args) {
    		//服务类
    		ServerBootstrap bootstrap = new ServerBootstrap();
    		
    		//boss和worker
    		EventLoopGroup boss = new NioEventLoopGroup();
    		EventLoopGroup worker = new NioEventLoopGroup();
    		
    		try {
    			//设置线程池
    			bootstrap.group(boss, worker);
    			
    			//设置socket工厂、
    			bootstrap.channel(NioServerSocketChannel.class);
    			
    			//设置管道工厂
    			bootstrap.childHandler(new ChannelInitializer<Channel>() {
    
    				@Override
    				protected void initChannel(Channel ch) throws Exception {
    					ch.pipeline().addLast(new IdleStateHandler(5, 5, 10));
    					ch.pipeline().addLast(new StringDecoder());
    					ch.pipeline().addLast(new StringEncoder());
    					ch.pipeline().addLast(new ServerHandler());
    				}
    			});
    			
    			//netty3中对应设置如下
    			//bootstrap.setOption("backlog", 1024);
    			//bootstrap.setOption("tcpNoDelay", true);
    			//bootstrap.setOption("keepAlive", true);
    			//设置参数，TCP参数
    			bootstrap.option(ChannelOption.SO_BACKLOG, 2048);//serverSocketchannel的设置，链接缓冲池的大小
    			bootstrap.childOption(ChannelOption.SO_KEEPALIVE, true);//socketchannel的设置,维持链接的活跃，清除死链接
    			bootstrap.childOption(ChannelOption.TCP_NODELAY, true);//socketchannel的设置,关闭延迟发送
    			
    			//绑定端口
    			ChannelFuture future = bootstrap.bind(8008);
    			
    			System.out.println("start");
    			
    			//等待服务端关闭
    			future.channel().closeFuture().sync();
    			
    		} catch (Exception e) {
    			e.printStackTrace();
    		} finally{
    			//释放资源
    			boss.shutdownGracefully();
    			worker.shutdownGracefully();
    		}
    	}
    }

测试步骤跟netty3一样的流程。

[代码下载][Link 1]

[20200614100939931.png]: https://img-blog.csdnimg.cn/20200614100939931.png
[2020061410112199.png]: https://img-blog.csdnimg.cn/2020061410112199.png
[20200614101112727.png]: https://img-blog.csdnimg.cn/20200614101112727.png
[20200614101218846.png]: https://img-blog.csdnimg.cn/20200614101218846.png
[2020061410131456.png]: https://img-blog.csdnimg.cn/2020061410131456.png
[Link 1]: https://github.com/ChenXbFrank/nettyLearnCode