netty如何使用 ChannelInboundHandlerAdapter相关理解

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pom

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
   <groupId>com.fly.study.netty</groupId>
    <artifactId>netty</artifactId>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.17.Final</version>
        </dependency>
    </dependencies>

</project>

主要代码

package demo.back;

import demo.util.PrintHandler;
import demo.util.ServerUtils;
import io.netty.channel.ChannelHandler;

/**
 * Created with IntelliJ IDEA
 * Description:
 * User: weijun.zou
 * Date: 2018-06-01
 * Time: 17:29
 */
@ChannelHandler.Sharable
public class Server extends PrintHandler {

    public static void main(String[] args) throws InterruptedException {
        ServerUtils.startServer(9999, new Server());
    }
}

package demo.back;

import demo.util.ClientUtils;
import demo.util.PrintHandler;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;

/**
 * Created with IntelliJ IDEA
 * Description:
 * User: weijun.zou
 * Date: 2018-06-01
 * Time: 17:45
 */
public class Client extends PrintHandler {

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        super.channelActive(ctx);
        final ChannelFuture f = ctx.writeAndFlush("client active");
        f.addListener((ChannelFutureListener) future -> {
            assert f == future;
            ctx.close();
        });
    }

    public static void main(String[] args) throws InterruptedException {
        ClientUtils.startClient("localhost", 9999, new Client());
    }
}

相关测试代码：

package demo.util;

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

/**
 * Created with IntelliJ IDEA
 * Description:
 * User: weijun.zou
 * Date: 2018-06-01
 * Time: 18:14
 */
public class PrintHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        System.out.println(info() + "read");
    }

    @Override
    public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
        System.out.println(info() + "registered");
    }

    @Override
    public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
        System.out.println(info() + "unregistered");
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println(info() + "active");
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println(info() + "inactive");
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        System.out.println(info() + "readComplete");
    }

    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        System.out.println(info() + "triggered");
    }

    @Override
    public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {
        System.out.println(info() + "changed");
    }

    protected String info() {
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return System.currentTimeMillis() + " " + this.getClass().getSimpleName() + ": ";
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}

package demo.util;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandler;
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.NioSocketChannel;

/**
 * Created with IntelliJ IDEA
 * Description:
 * User: weijun.zou
 * Date: 2018-06-01
 * Time: 17:37
 */
public class ClientUtils {
    public static void startClient(String host,int port,ChannelHandler... handlers) throws InterruptedException {
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap(); // (1)
            b.group(workerGroup); // (2)
            b.channel(NioSocketChannel.class); // (3)
            b.option(ChannelOption.SO_KEEPALIVE, true); // (4)
            b.handler(new ChannelInitializer<SocketChannel>() {
                @Override
                public void initChannel(SocketChannel ch) throws Exception {
                    ch.pipeline().addLast(handlers);
                }
            });
            ChannelFuture f = b.connect(host, port).sync(); // (5)
            f.channel().closeFuture().sync();
        } finally {
            workerGroup.shutdownGracefully();
        }
    }
}

package demo.util;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandler;
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;

/**
 * Created with IntelliJ IDEA
 * Description:
 * User: weijun.zou
 * Date: 2018-06-01
 * Time: 17:34
 */
public class ServerUtils {

    public static void startServer(int port, ChannelHandler... handlers) throws InterruptedException {
        EventLoopGroup bossGroup = new NioEventLoopGroup(); // (1)
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap(); // (2)
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class) // (3)
                    .childHandler(new ChannelInitializer<SocketChannel>() { // (4)
                        @Override
                        public void initChannel(SocketChannel ch) throws Exception {
                            ch.pipeline().addLast(handlers);
                        }
                    })
                    .option(ChannelOption.SO_BACKLOG, 128)          // (5)
                    .childOption(ChannelOption.SO_KEEPALIVE, true); // (6)
            ChannelFuture f = b.bind(port).sync(); // (7)
            f.channel().closeFuture().sync();
        } finally {
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
        }
    }
}