Netty入门

本文的示例代码参考NettyBasic

目录

• 开始

• Netty

• Pipeline

开始

spring init -b 1.5.6.RELEASE -dweb --build gradle NettyBasic

vim src/main/java/com/example/NettyBasic/NettyServer.java

package com.example.NettyBasic;

public class NettyServer {
    public static void start() {
        System.out.println("server start");
    }
}

vim src/main/java/com/example/NettyBasic/DemoApplication.java

package com.example.NettyBasic;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
        NettyServer.start();
    }
}

• 测试

./gradlew bootrun

server start

Netty

vim build.gradle

# 省略了未修改代码
dependencies {
    compile('org.springframework.boot:spring-boot-starter-web')
    testCompile('org.springframework.boot:spring-boot-starter-test')
    compile('io.netty:netty-all:4.1.25.Final')
}

vim src/main/java/com/example/NettyBasic/NettyServer.java

package com.example.NettyBasic;

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;

public class NettyServer {
    public static void start() {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .childOption(ChannelOption.SO_KEEPALIVE, true)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline channelPipeline = ch.pipeline();
                            channelPipeline.addLast(new LoggerHandler());
                        }
                    });

            System.out.println("server start");
            ChannelFuture channelFuture = serverBootstrap.bind(10001).sync();
            channelFuture.channel().closeFuture().sync();
            System.out.println("server closed");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

vim src/main/java/com/example/NettyBasic/LoggerHandler.java

package com.example.NettyBasic;

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

public class LoggerHandler extends ChannelInboundHandlerAdapter {

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

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        System.out.println("read complete");
    }
}

• 测试

# server
./gradlew bootrun

# client
telnet 127.0.0.1 10001

# server
server start
read: PooledUnsafeDirectByteBuf(ridx: 0, widx: 7, cap: 1024)
read complete
read: PooledUnsafeDirectByteBuf(ridx: 0, widx: 7, cap: 1024)
read complete

# client
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
hello
world

Pipeline

vim src/main/java/com/example/NettyBasic/NettyServer.java

public class NettyServer {
    public static void start() {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .childOption(ChannelOption.SO_KEEPALIVE, true)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline channelPipeline = ch.pipeline();
                            channelPipeline.addLast(new StringDecoder());
                            channelPipeline.addLast(new LoggerHandler());
                        }
                    });

            System.out.println("server start");
            ChannelFuture channelFuture = serverBootstrap.bind(10001).sync();
            channelFuture.channel().closeFuture().sync();
            System.out.println("server closed");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

• 测试

# server
./gradlew bootrun

# client 1
telnet 127.0.0.1 10001

# client 2
telnet 127.0.0.1 10001

# server
server start
read: hello
read complete
read: world
read complete
read: hello
read complete
read: world
read complete

# client 1
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
hello
world

# client 2
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
hello
world

参考

• Netty实战

• Netty Project

• Netty入门教程 -- 认识Netty