• hadoop26----netty,多个handler


    k客户端:

    package cn.itcast_03_netty.sendorder.client;
    
    import io.netty.bootstrap.Bootstrap;
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelInitializer;
    import io.netty.channel.EventLoopGroup;
    import io.netty.channel.nio.NioEventLoopGroup;
    import io.netty.channel.socket.SocketChannel;
    import io.netty.channel.socket.nio.NioSocketChannel;
    
    import java.net.InetSocketAddress;
    
    import cn.itcast_03_netty.sendobject.coder.PersonEncoder;
    
    /**
     * • 连接服务器 • 写数据到服务器 • 等待接受服务器返回相同的数据 • 关闭连接
     * 
     * @author wilson
     *
     */
    public class EchoClient {
    
        private final String host;
        private final int port;
    
        public EchoClient(String host, int port) {
            this.host = host;
            this.port = port;
        }
    
        public void start() throws Exception {
            EventLoopGroup nioEventLoopGroup = null;
            try {
                // 客户端引导类
                Bootstrap bootstrap = new Bootstrap();
                // EventLoopGroup可以理解为是一个线程池,这个线程池用来处理连接、接受数据、发送数据
                nioEventLoopGroup = new NioEventLoopGroup();
                bootstrap.group(nioEventLoopGroup)//多线程处理
                        .channel(NioSocketChannel.class)//指定通道类型为NioServerSocketChannel,一种异步模式,OIO阻塞模式为OioServerSocketChannel
                        .remoteAddress(new InetSocketAddress(host, port))//地址
                        .handler(new ChannelInitializer<SocketChannel>() {//业务处理类
                                    @Override
                                    protected void initChannel(SocketChannel ch)
                                            throws Exception {
                                        ch.pipeline().addLast(new EchoClientHandler());//注册handler
                                    }
                                });
                // 链接服务器
                ChannelFuture channelFuture = bootstrap.connect().sync();
                channelFuture.channel().closeFuture().sync();
            } finally {
                nioEventLoopGroup.shutdownGracefully().sync();
            }
        }
    
        public static void main(String[] args) throws Exception {
            new EchoClient("localhost", 20000).start();
        }
    }
    
    
    /*
    客户端连接服务器,开始发送数据……
    client 读取server数据..
    服务端数据为 :Sun May 13 10:32:47 CST 2018
    */
    package cn.itcast_03_netty.sendorder.client;
    
    import io.netty.buffer.ByteBuf;
    import io.netty.buffer.Unpooled;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.SimpleChannelInboundHandler;
    import cn.itcast_03_netty.sendobject.bean.Person;
    
    public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {
        // 客户端连接服务器后被调用
        @Override
        public void channelActive(ChannelHandlerContext ctx) throws Exception {
            System.out.println("客户端连接服务器,开始发送数据……");
            byte[] req = "QUERY TIME ORDER".getBytes();//消息
            ByteBuf firstMessage = Unpooled.buffer(req.length);//发送类
            firstMessage.writeBytes(req);//发送
            ctx.writeAndFlush(firstMessage);//flush
        }
    
        // • 从服务器接收到数据后调用
        @Override
        protected void channelRead0(ChannelHandlerContext ctx, ByteBuf msg)
                throws Exception {
            System.out.println("client 读取server数据..");
            // 服务端返回消息后
            ByteBuf buf = (ByteBuf) msg;
            byte[] req = new byte[buf.readableBytes()];
            buf.readBytes(req);
            String body = new String(req, "UTF-8");
            System.out.println("服务端数据为 :" + body);
        }
    
        // • 发生异常时被调用
        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
                throws Exception {
            System.out.println("client exceptionCaught..");
            // 释放资源
            ctx.close();
        }
    }

    服务端:

    package cn.itcast_03_netty.sendorder.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.EventLoopGroup;
    import io.netty.channel.nio.NioEventLoopGroup;
    import io.netty.channel.socket.nio.NioServerSocketChannel;
    import cn.itcast_03_netty.sendobject.coder.PersonDecoder;
    
    /**
     * • 配置服务器功能,如线程、端口 • 实现服务器处理程序,它包含业务逻辑,决定当有一个请求连接或接收数据时该做什么
     * 
     * @author wilson
     *
     */
    public class EchoServer {
    
        private final int port;
    
        public EchoServer(int port) {
            this.port = port;
        }
    
        public void start() throws Exception {
            EventLoopGroup eventLoopGroup = null;
            try {
                //server端引导类
                ServerBootstrap serverBootstrap = new ServerBootstrap();
                //连接池处理数据
                eventLoopGroup = new NioEventLoopGroup();
                serverBootstrap.group(eventLoopGroup)
                .channel(NioServerSocketChannel.class)//指定通道类型为NioServerSocketChannel,一种异步模式,OIO阻塞模式为OioServerSocketChannel
                .localAddress("localhost",port)//设置InetSocketAddress让服务器监听某个端口已等待客户端连接。
                .childHandler(new ChannelInitializer<Channel>() {//设置childHandler执行所有的连接请求
                    @Override
                    protected void initChannel(Channel ch) throws Exception {
                        // 注册两个InboundHandler,执行顺序为注册顺序,所以应该是InboundHandler1 InboundHandler2
                        // 注册两个OutboundHandler,执行顺序为注册顺序的逆序,所以应该是OutboundHandler2 OutboundHandler1
                        ch.pipeline().addLast(new EchoInHandler1());
                        ch.pipeline().addLast(new EchoInHandler2());
                        ch.pipeline().addLast(new EchoOutHandler1());
                        ch.pipeline().addLast(new EchoOutHandler2()); 
                        
                    }
                        });
                // 最后绑定服务器等待直到绑定完成,调用sync()方法会阻塞直到服务器完成绑定,然后服务器等待通道关闭,因为使用sync(),所以关闭操作也会被阻塞。
                ChannelFuture channelFuture = serverBootstrap.bind().sync();
                System.out.println("开始监听,端口为:" + channelFuture.channel().localAddress());
                channelFuture.channel().closeFuture().sync();
            } finally {
                eventLoopGroup.shutdownGracefully().sync();
            }
        }
    
        public static void main(String[] args) throws Exception {
            new EchoServer(20000).start();
        }
    }
    
    /*
    开始监听,端口为:/127.0.0.1:20000
    in1
    in2
    接收客户端数据:QUERY TIME ORDER
    server向client发送数据
    Complete1
    */
    package cn.itcast_03_netty.sendorder.server;
    
    import io.netty.buffer.ByteBuf;
    import io.netty.buffer.Unpooled;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.ChannelInboundHandlerAdapter;
    
    import java.util.Date;
    
    import cn.itcast_03_netty.sendobject.bean.Person;
    
    public class EchoInHandler1 extends ChannelInboundHandlerAdapter {
    
        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg)
                throws Exception {
            System.out.println("in1");
             // 通知执行下一个InboundHandler
            ctx.fireChannelRead(msg);
        }
    
        @Override
        public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
            System.out.println("Complete1");
            ctx.flush();//刷新后才将数据发出到SocketChannel
        }
    
        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
                throws Exception {
            cause.printStackTrace();
            ctx.close();
        }
    
    }
    package cn.itcast_03_netty.sendorder.server;
    
    import io.netty.buffer.ByteBuf;
    import io.netty.buffer.Unpooled;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.ChannelInboundHandlerAdapter;
    
    import java.util.Date;
    
    import cn.itcast_03_netty.sendobject.bean.Person;
    
    public class EchoInHandler2 extends ChannelInboundHandlerAdapter {
    
        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg)
                throws Exception {
            System.out.println("in2");
            ByteBuf buf = (ByteBuf) msg;
            byte[] req = new byte[buf.readableBytes()];
            buf.readBytes(req);
            String body = new String(req, "UTF-8");
            System.out.println("接收客户端数据:" + body);
            //向客户端写数据
            System.out.println("server向client发送数据");
            String currentTime = new Date(System.currentTimeMillis()).toString();
            ByteBuf resp = Unpooled.copiedBuffer(currentTime.getBytes());
            ctx.write(resp);
            
        }
    
        @Override
        public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
            System.out.println("Complete2");
            ctx.flush();//刷新后才将数据发出到SocketChannel
        }
    
        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
                throws Exception {
            cause.printStackTrace();
            ctx.close();
        }
    
    }
    package cn.itcast_03_netty.sendorder.server;
    
    import java.util.Date;
    
    import io.netty.buffer.ByteBuf;
    import io.netty.buffer.Unpooled;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.ChannelOutboundHandlerAdapter;
    import io.netty.channel.ChannelPromise;
    
    public class EchoOutHandler1 extends ChannelOutboundHandlerAdapter {
        @Override
        // 向client发送消息
        public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
            System.out.println("out1");
            /*System.out.println(msg);*/
            
            String currentTime = new Date(System.currentTimeMillis()).toString();
            ByteBuf resp = Unpooled.copiedBuffer(currentTime.getBytes());
            ctx.write(resp);
            ctx.flush();
           }
    }
    package cn.itcast_03_netty.sendorder.server;
    
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.ChannelOutboundHandlerAdapter;
    import io.netty.channel.ChannelPromise;
    
    public class EchoOutHandler2 extends ChannelOutboundHandlerAdapter {
    
         @Override
            public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
                System.out.println("out2");
                // 执行下一个OutboundHandler
                /*System.out.println("at first..msg = "+msg);
                msg = "hi newed in out2";*/
                super.write(ctx, msg, promise);
            }
    
    }
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  • 原文地址:https://www.cnblogs.com/yaowen/p/9031476.html
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