netty之Netty心跳服务与断线重连

前言

使用netty中，需要监测服务是否稳定以及在网络异常链接断开时候可以自动重连。需要实现监听；f.addListener(new MyChannelFutureListener())
代码目录结构

package com.lm.demo.netty.client;

import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.EventLoop;

import java.util.concurrent.TimeUnit;


public class MyChannelFutureListener implements ChannelFutureListener {
    @Override
    public void operationComplete(ChannelFuture channelFuture) throws Exception {
        if (channelFuture.isSuccess()) {
            System.out.println("client start done. {关注明哥，获取源码}");
            return;
        }
        final EventLoop loop = channelFuture.channel().eventLoop();
        loop.schedule(new Runnable() {
            @Override
            public void run() {
                try {
                    new NettyClient().connect("127.0.0.1", 7397);
                    System.out.println("client start done. {关注明哥，获取源码}");
                    Thread.sleep(500);
                } catch (Exception e) {
                    System.out.println("client start error go reconnect ... {关注明哥，获取源码}");
                }
            }
        }, 1L, TimeUnit.SECONDS);
    }
}

package com.lm.demo.netty.client;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.socket.SocketChannel;

import java.text.SimpleDateFormat;
import java.util.Date;


public class MyClientHandler extends ChannelInboundHandlerAdapter {

    /**
     * 当客户端主动链接服务端的链接后，这个通道就是活跃的了。也就是客户端与服务端建立了通信通道并且可以传输数据
     */
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        SocketChannel channel = (SocketChannel) ctx.channel();
        System.out.println("链接报告开始");
        System.out.println("链接报告信息：本客户端链接到服务端。channelId：" + channel.id());
        System.out.println("链接报告IP:" + channel.localAddress().getHostString());
        System.out.println("链接报告Port:" + channel.localAddress().getPort());
        System.out.println("链接报告完毕");
    }

    /**
     * 当客户端主动断开服务端的链接后，这个通道就是不活跃的。也就是说客户端与服务端的关闭了通信通道并且不可以传输数据
     */
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("断开链接重连" + ctx.channel().localAddress().toString());
        //使用过程中断线重连
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    new NettyClient().connect("127.0.0.1", 7397);
                    System.out.println(" client start done. {关注明哥，获取源码}");
                    Thread.sleep(500);
                } catch (Exception e){
                    System.out.println("client start error go reconnect ... {关注明哥，获取源码}");
                }
            }
        }).start();
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        //接收msg消息{与上一章节相比，此处已经不需要自己进行解码}
        System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + " 接收到消息：" + msg);
    }

    /**
     * 抓住异常，当发生异常的时候，可以做一些相应的处理，比如打印日志、关闭链接
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        System.out.println("异常信息，断开重连：\r\n" + cause.getMessage());
        ctx.close();
    }

}

public class NettyClient {

    public static void main(String[] args) {
        new NettyClient().connect("127.0.0.1", 7397);
    }

    public void connect(String inetHost, int inetPort) {
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(workerGroup);
            b.channel(NioSocketChannel.class);
            b.option(ChannelOption.AUTO_READ, true);
            b.handler(new MyChannelInitializer());
            ChannelFuture f = b.connect(inetHost, inetPort).sync();
            f.addListener(new MyChannelFutureListener()); //添加监听，处理重连
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            workerGroup.shutdownGracefully();
        }
    }

}

public class MyServerHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        super.userEventTriggered(ctx, evt);
        if (evt instanceof IdleStateEvent) {
            IdleStateEvent e = (IdleStateEvent) evt;
            if (e.state() == IdleState.READER_IDLE) {
                System.out.println("关注明哥提醒=> Reader Idle");
                ctx.writeAndFlush("读取等待：公众号关注明哥，客户端你在吗[ctx.close()]{我结尾是一个换行符用于处理半包粘包}... ...\r\n");
                ctx.close();
            } else if (e.state() == IdleState.WRITER_IDLE) {
                System.out.println("关注明哥提醒=> Write Idle");
                ctx.writeAndFlush("写入等待：公众号关注明哥，客户端你在吗{我结尾是一个换行符用于处理半包粘包}... ...\r\n");
            } else if (e.state() == IdleState.ALL_IDLE) {
                System.out.println("关注明哥提醒=> All_IDLE");
                ctx.writeAndFlush("全部时间：公众号关注明哥，客户端你在吗{我结尾是一个换行符用于处理半包粘包}... ...\r\n");
            }
        }
        ctx.flush();
    }

    /**
     * 当客户端主动链接服务端的链接后，这个通道就是活跃的了。也就是客户端与服务端建立了通信通道并且可以传输数据
     */
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        SocketChannel channel = (SocketChannel) ctx.channel();
        System.out.println("链接报告开始");
        System.out.println("链接报告信息：有一客户端链接到本服务端");
        System.out.println("链接报告IP:" + channel.localAddress().getHostString());
        System.out.println("链接报告Port:" + channel.localAddress().getPort());
        System.out.println("链接报告完毕");
        //通知客户端链接建立成功
        String str = "通知客户端链接建立成功" + " " + new Date() + " " + channel.localAddress().getHostString() + "\r\n";
        ctx.writeAndFlush(str);
    }

    /**
     * 当客户端主动断开服务端的链接后，这个通道就是不活跃的。也就是说客户端与服务端的关闭了通信通道并且不可以传输数据
     */
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("客户端断开链接" + ctx.channel().localAddress().toString());
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        //接收msg消息{与上一章节相比，此处已经不需要自己进行解码}
        System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + " 接收到消息：" + msg);
        //通知客户端链消息发送成功
        String str = "服务端收到：" + new Date() + " " + msg + "\r\n";
        ctx.writeAndFlush(str);
    }

    /**
     * 抓住异常，当发生异常的时候，可以做一些相应的处理，比如打印日志、关闭链接
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        ctx.close();
        System.out.println("异常信息：\r\n" + cause.getMessage());
    }

}

package com.lm.demo.netty.server;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;


public class NettyServer {

    public static void main(String[] args) {
        new NettyServer().bing(7397);
    }

    private void bing(int port) {
        //配置服务端NIO线程组
        EventLoopGroup parentGroup = new NioEventLoopGroup(); //NioEventLoopGroup extends MultithreadEventLoopGroup Math.max(1, SystemPropertyUtil.getInt("io.netty.eventLoopThreads", NettyRuntime.availableProcessors() * 2));
        EventLoopGroup childGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(parentGroup, childGroup)
                    .channel(NioServerSocketChannel.class)    //非阻塞模式
                    .option(ChannelOption.SO_BACKLOG, 128)
                    .childHandler(new MyChannelInitializer());
            ChannelFuture f = b.bind(port).sync();
            System.out.println("server start done. {关注明哥，获取源码}");
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            childGroup.shutdownGracefully();
            parentGroup.shutdownGracefully();
        }

    }

}

测试结果
启动NettyServer *在心跳中设置ctx.close();模拟断开链接，等待重连

启动NettyClient

好了到这里就结束了netty之Netty心跳服务与断线重连的学习，大家一定要跟着动手操作起来。需要的源码的 可si我获取；

原文地址：https://blog.csdn.net/CSDN_LiMingfly/article/details/142700586

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