Netty心跳服务

目录

• 客户端
• 服务端

客户端

package com.cnblogs.javalouvre;

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.timeout.IdleStateEvent;
import io.netty.handler.timeout.IdleStateHandler;
import io.netty.util.CharsetUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.net.InetSocketAddress;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import static io.netty.handler.timeout.IdleState.WRITER_IDLE;

public class Client {

    private ScheduledExecutorService    executor = Executors.newScheduledThreadPool(1);
    private static final Logger         log      = LoggerFactory.getLogger(Client.class);
    private static final int            port     = 8080;
    private static final String         ip       = "127.0.0.1";
    private static final EventLoopGroup group    = new NioEventLoopGroup();

    public static void main(String[] args) {
        new Client().connect(port, ip);
    }

    private void connect(final int port, final String ip) {
        final Bootstrap bootstrap = new Bootstrap();
        bootstrap.group(group)
                .channel(NioSocketChannel.class)
                .option(ChannelOption.TCP_NODELAY, Boolean.TRUE)
                .handler(new ChannelInitializer<SocketChannel>() {

                    @Override
                    protected void initChannel(SocketChannel ch) throws Exception {
                        final ChannelPipeline pipeline = ch.pipeline();
                        pipeline.addLast(new LoggingHandler());
                        pipeline.addLast(new IdleStateHandler(0, 5, 0)); // 写空闲5秒
                        pipeline.addLast(new StringDecoder());
                        pipeline.addLast(new StringEncoder());
                        pipeline.addLast(new HeartBeatRequestHandler());
                    }

                });

        try {
            final ChannelFuture channelFuture = bootstrap.connect(new InetSocketAddress(ip, port)).sync();
            channelFuture.addListener(new ChannelFutureListener() {

                @Override
                public void operationComplete(ChannelFuture future) throws Exception {
                    if (!future.isSuccess()) {
                        log.error("连接服务失败");
                    }
                }

            });
            channelFuture.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            executor.execute(new Runnable() {

                @Override
                public void run() {
                    try {
                        TimeUnit.SECONDS.sleep(1);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                    log.info("开始重连");

                    connect(port, ip);
                }

            });
        }
    }
}

@ChannelHandler.Sharable
class HeartBeatRequestHandler extends ChannelInboundHandlerAdapter {

    private static final Logger log = LoggerFactory.getLogger(HeartBeatRequestHandler.class);
    private static final ByteBuf HEARTBEAT_SEQUENCE = Unpooled.unreleasableBuffer(Unpooled.copiedBuffer("HeartBeat", CharsetUtil.UTF_8));

    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        if (evt instanceof IdleStateEvent) {
            final IdleStateEvent event = (IdleStateEvent) evt;
            if (WRITER_IDLE == event.state()) {
                ctx.writeAndFlush(HEARTBEAT_SEQUENCE.duplicate());
            }
        } else {
            super.userEventTriggered(ctx, evt);
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        log.error(cause.getMessage());
        ctx.fireExceptionCaught(cause);
    }

}

服务端

package com.cnblogs.javalouvre;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
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.logging.LoggingHandler;
import io.netty.handler.timeout.ReadTimeoutHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Server {

    private static final Logger log = LoggerFactory.getLogger(Server.class);
    private static final int port = 8080;

    private void bind(final int port) {
        final EventLoopGroup parent = new NioEventLoopGroup();
        final EventLoopGroup child = new NioEventLoopGroup();
        final ServerBootstrap bootstrap = new ServerBootstrap();
        bootstrap.group(parent, child)
                .channel(NioServerSocketChannel.class)
                .option(ChannelOption.SO_BACKLOG, 100)
                .childOption(ChannelOption.SO_KEEPALIVE, Boolean.TRUE)
                .childHandler(new ChannelInitializer<SocketChannel>() {

                    @Override
                    protected void initChannel(SocketChannel ch) throws Exception {
                        ch.pipeline().addLast(new LoggingHandler());
                        ch.pipeline().addLast(new ReadTimeoutHandler(10)); // 10秒未读取到消息，判定读超时
                        ch.pipeline().addLast(new StringDecoder());
                        ch.pipeline().addLast(new StringEncoder());
                    }

                });
        try {
            final ChannelFuture channelFuture = bootstrap.bind(port).sync();
            channelFuture.addListener(new ChannelFutureListener() {

                @Override
                public void operationComplete(ChannelFuture future) throws Exception {
                    if (!future.isSuccess()) {
                        log.error("服务启动失败");
                    }
                }

            });
            channelFuture.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            child.shutdownGracefully();
            parent.shutdownGracefully();
        }
    }

    public static void main(String[] args) {
        new Server().bind(port);
    }
}