Netty的第一个应用----学习孙哥&不良人课程，整理学习笔记文章 【https://space.bilibili.com/284638819】

Netty的第一个应用

1. 环境搭建

<dependency>
  <groupId>io.netty</groupId>
  <artifactId>netty-all</artifactId>
  <version>4.1.45.Final</version>
</dependency>

<dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>4.13.2</version>
  <scope>test</scope>
</dependency>

<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-api</artifactId>
  <version>1.7.32</version>
</dependency>

<dependency>
  <groupId>ch.qos.logback</groupId>
  <artifactId>logback-classic</artifactId>
  <version>1.2.9</version>
</dependency>

2. 第一个程序分析 [NIO]

public class MyNettyServer {
    public static void main(String[] args) {
        ServerBootstrap serverBootstrap = new ServerBootstrap();

        serverBootstrap.channel(NioServerSocketChannel.class);

        //创建了一组线程 通过死循环 监控状态 accept read write
        serverBootstrap.group(new NioEventLoopGroup());

        //ServerSocketChannel  SocketChannel
        serverBootstrap.childHandler(new ChannelInitializer<NioSocketChannel>() {
            @Override
            /*
                 channel 接通 监控 accept rw 处理 通过流水线 用handler进行处理 。
             */
            protected void initChannel(NioSocketChannel ch) throws Exception {
                //ByteBuf 字节--->字符
                //ch.pipeline().addLast(new StringDecoder());
                ch.pipeline().addLast(new ChannelInboundHandlerAdapter() {
                    @Override
                    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
                        ByteBuf buffer = (ByteBuf) msg;
                        String result = ((ByteBuf) msg).toString(Charset.defaultCharset());
                        System.out.println("result = " + result);
                    }
                });
            }
        });

        serverBootstrap.bind(8000);


    }

}

public class MyNettyClient {
    public static void main(String[] args) throws InterruptedException {
        Bootstrap bootstrap = new Bootstrap();

        bootstrap.channel(NioSocketChannel.class);

        // 为什么client 引入事件 循环 组
        // client Netty 做多线程 异步
        // 连接服务端 一个线程
        // 通信 做成一个线程
        // 异步处理  连接 --->
        //          IO操作
        bootstrap.group(new NioEventLoopGroup());

        bootstrap.handler(new ChannelInitializer<NioSocketChannel>() {
            @Override
            protected void initChannel(NioSocketChannel ch) throws Exception {
                ch.pipeline().addLast(new StringEncoder());
            }
        });

        ChannelFuture connect = bootstrap.connect(new InetSocketAddress(8000));
        connect.sync();
        //创建了新的线程 进行写操作
        Channel channel = connect.channel();
        channel.writeAndFlush("hello suns");


    }
}