netty 5 心跳

netty 5 心跳

package com.server;

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;

public class server {

    public static void main(String[] args){
        
        // 创建一个 server 服务
        ServerBootstrap server = new ServerBootstrap();

        EventLoopGroup boss = new NioEventLoopGroup();
        EventLoopGroup worker = new NioEventLoopGroup();
        // 绑定 
        try{
            server.group(boss, worker);
            
            server.channel( NioServerSocketChannel.class);
            
            server.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
            server.option(ChannelOption.SO_BACKLOG, 2048);//serverSocketchannel的设置，链接缓冲池的大小
            server.childOption(ChannelOption.SO_KEEPALIVE, true);//socketchannel的设置,维持链接的活跃，清除死链接
            server.childOption(ChannelOption.TCP_NODELAY, true);//socketchannel的设置,关闭延迟发送
            
            ChannelFuture future = server.bind(10001);
            System.out.println("start！");
            //等待服务端关闭
            future.channel().closeFuture().sync();
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            worker.shutdownGracefully();
            boss.shutdownGracefully();
        }
    }
}

ServerHandler  代码

package com.server;

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;

public class ServerHandler extends SimpleChannelInboundHandler<String> {

    
    
    @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){
                System.out.println("你很久没有联系了");
                ChannelFuture future = ctx.writeAndFlush("you will close");
                future.addListener( new ChannelFutureListener(){
                    @Override
                    public void operationComplete(ChannelFuture future)
                            throws Exception {
                        // TODO Auto-generated method stub
                        ctx.channel().close();
                    }
                    
                });
            }
        }else{
            super.userEventTriggered(ctx, evt);
        }
    }

    @Override
    protected void messageReceived(ChannelHandlerContext ctx, String msg)
            throws Exception {
        System.out.println(msg);
        ctx.channel().writeAndFlush("hi");
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
            throws Exception {
        // TODO Auto-generated method stub
        super.exceptionCaught(ctx, cause);
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        // TODO Auto-generated method stub
        System.out.println("欢迎链接");
        super.channelActive(ctx);
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        // TODO Auto-generated method stub
        System.out.println("断开链接");
        super.channelInactive(ctx);
    }
    
    

}

注意需要引入 netty 5 的jar包

ch.pipeline().addLast(new IdleStateHandler(5, 5, 10));  给管道加入一个心跳事件，  5 读超时 5写超时 10 读写超时   超过5秒没有读就会发起一个读超时事件
Handler 中的 userEventTriggered  这个方法为心跳触发事件，当事件类型为 IdleStateEvent  为超时类型事件  当返回的状态为 IdleState.ALL_IDLE  为读写超时