netty5简单例子，快速入门

朴灿烈づ我的快乐病毒、 2022-05-27 11:35 245阅读 0赞

添加maven引用：

<dependency>
        <groupId>io.netty</groupId>
        <artifactId>netty-all</artifactId>
        <version>5.0.0.Alpha2</version>
    </dependency>

1，discard丢弃服务   接收到数据后只做处理不做回应

package nettyStudy;
    
    import io.netty.buffer.ByteBuf;
    import io.netty.channel.ChannelHandlerAdapter;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.util.CharsetUtil;
    import io.netty.util.ReferenceCountUtil;
    
    public class DisCardServerHandler extends ChannelHandlerAdapter {
        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
            try {
                ByteBuf in = (ByteBuf) msg;
                System.out.println(in.toString(CharsetUtil.UTF_8));
            } finally {
                ReferenceCountUtil.release(msg);
            }
        }
    
        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
            cause.printStackTrace();
            ctx.close();
        }
    }

2，echo响应服务

package nettyStudy;
    
    import io.netty.buffer.ByteBuf;
    import io.netty.channel.ChannelHandlerAdapter;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.util.CharsetUtil;
    
    public class ResponseServerHandler extends ChannelHandlerAdapter {
        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
            ByteBuf in = (ByteBuf) msg;
            System.out.println(in.toString(CharsetUtil.UTF_8));
            ctx.write(msg);
        }
        @Override
        public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
            ctx.flush();
        }
    
        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
            cause.printStackTrace();
        }
    }

3，时间协议的服务

package nettyStudy;
    
    import io.netty.bootstrap.ServerBootstrap;
    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.SocketChannel;
    import io.netty.channel.socket.nio.NioServerSocketChannel;
    
    public class TimeServer {
        private int port;
    
        public TimeServer(int port) {
            super();
            this.port = port;
        }
    
        public void run() throws Exception {
            EventLoopGroup bossGroup = new NioEventLoopGroup();
            EventLoopGroup workerGroup = new NioEventLoopGroup();
            System.out.println("准备运行端口:" + port);
            try {
                ServerBootstrap b = new ServerBootstrap();
                b = b.group(bossGroup, workerGroup)
                        .channel(NioServerSocketChannel.class)
                        .childHandler(new ChannelInitializer<SocketChannel>() {
                            @Override
                            protected void initChannel(SocketChannel ch) throws Exception {
                                ch.pipeline().addLast(new TimeServerHandler());
                            }
                        })
                        .option(ChannelOption.SO_BACKLOG, 128)
                        .childOption(ChannelOption.SO_KEEPALIVE, true);
                ChannelFuture f = b.bind(port).sync();
                f.channel().closeFuture().sync();
            } finally {
                workerGroup.shutdownGracefully();
                bossGroup.shutdownGracefully();
            }
        }
    
        public static void main(String[] args) throws Exception {
            int port;
            if (args.length > 0){
                port = Integer.parseInt(args[0]);
            }
            else{
                port = 8080;
            }
            new TimeServer(port).run();
            System.out.println("server:run()");
        }
    }
    
    
    package nettyStudy;
    
    import io.netty.buffer.ByteBuf;
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelFutureListener;
    import io.netty.channel.ChannelHandlerAdapter;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.util.CharsetUtil;
    
    import java.util.Scanner;
    
    public class TimeClientHandler extends ChannelHandlerAdapter {
        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
            ByteBuf in = (ByteBuf) msg;
            System.out.println("server:" + in.toString(CharsetUtil.UTF_8));
            System.out.println("输入应答server的信息:");
            Scanner cin = new Scanner(System.in);
            String content = cin.nextLine();
            final ByteBuf bb = ctx.alloc().buffer();
            bb.writeBytes(content.getBytes());
            final ChannelFuture f = ctx.writeAndFlush(bb);
            f.addListener(new ChannelFutureListener() {
                @Override
                public void operationComplete(ChannelFuture future) throws Exception {
                    System.out.println("发送成功");
                }
            });
        }
    
        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
            cause.printStackTrace();
        }
    }
    
    
    package nettyStudy;
    
    import io.netty.bootstrap.Bootstrap;
    import io.netty.channel.*;
    import io.netty.channel.nio.NioEventLoopGroup;
    import io.netty.channel.socket.SocketChannel;
    import io.netty.channel.socket.nio.NioSocketChannel;
    
    public class TimeClient {
        public static void main(String[] args) throws InterruptedException {
            String host = "127.0.0.1";
            int port = 8080;
            EventLoopGroup workergroup = new NioEventLoopGroup();
            try {
                Bootstrap b = new Bootstrap();
                b.group(workergroup);
                b.channel(NioSocketChannel.class);
                b.option(ChannelOption.SO_KEEPALIVE, true);
                b.handler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel ch) throws Exception {
                        ch.pipeline().addLast(new TimeClientHandler());
                    }
                });
    
                ChannelFuture f = b.connect(host, port).sync();
                f.channel().closeFuture().sync();
            } finally {
                workergroup.shutdownGracefully();
            }
        }
    }

import io.netty.buffer.ByteBuf;
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelFutureListener;
    import io.netty.channel.ChannelHandlerAdapter;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.util.CharsetUtil;
    import io.netty.util.ReferenceCountUtil;
    
    import java.util.Scanner;
    
    public class TimeServerHandler extends ChannelHandlerAdapter {
        @Override
        public void channelActive(final ChannelHandlerContext ctx) throws Exception {
            Scanner cin = new Scanner(System.in);
            System.out.println("请输入发送的消息:");
            String name = "Hello " + cin.nextLine();
    //        String name = "hello world";
            final ByteBuf time = ctx.alloc().buffer(4);
            time.writeBytes(name.getBytes());
            final ChannelFuture f = ctx.writeAndFlush(time);
            f.addListener(new ChannelFutureListener() {
                @Override
                public void operationComplete(ChannelFuture future) throws Exception {
                    assert f == future;
                    ctx.close();
                }
            });
        }
    
        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
            try {
                ByteBuf in = (ByteBuf) msg;
                System.out.println("client:" + in.toString(CharsetUtil.UTF_8));
            } finally {
                ReferenceCountUtil.release(msg);
            }
        }
    
        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
            cause.printStackTrace();
            ctx.close();
        }
    }