Netty 异步模型 ChannelFuture

偏执的太偏执、 2023-10-01 16:38 5阅读 0赞

#### Netty 异步模型 ChannelFuture ####

*  一、异步模型的概念
 *   *  1.实现的效果
     *  2.ChannelFuture类的接口方法
 *  二、调用说明
 *   *  1.服务启动类
     *  2.启动服务
     *   *  1.启动日志
         *  2.结果分析

## 一、异步模型的概念 ##

### 1.实现的效果 ###

1.异步，即操作发起后，通过回调告知结果
    2.Netty中的IO操作都是异步的，如bind、write、connect等，会返回一个ChannelFuture对象
    3.通过Future-Listener机制获取IO操作结果，降低IO操作阻塞的概率；对高并发抗压能力强

### 2.ChannelFuture类的接口方法 ###

Channel channel();
    ChannelFuture addListener(GenericFutureListener<? extends Future<? super Void>> listener);
    ChannelFuture addListeners(GenericFutureListener<? extends Future<? super Void>>... listeners);
    ChannelFuture removeListener(GenericFutureListener<? extends Future<? super Void>> listener);
    ChannelFuture removeListeners(GenericFutureListener<? extends Future<? super Void>>... listeners);
    ChannelFuture sync() throws InterruptedException;
    ChannelFuture syncUninterruptibly();
    ChannelFuture await() throws InterruptedException;
    ChannelFuture awaitUninterruptibly();

## 二、调用说明 ##

### 1.服务启动类 ###

package com.example.netty.server;
    
    import com.example.netty.server.handler.NettyServerHandler;
    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;
    
    /**
     * Description: Netty服务端
     *
     * @Author: zhx & moon hongxu_1234@163.com
     * @Date: 2021-11-14 23:31
     * @version: V1.0.0
     */
    public class NettyServer {
        
    
        public static void main(String[] args) throws InterruptedException {
        
    
            //创建BossGroup 和 WorkerGroup
            /**
             * 1.创建两个线程组
             * 2.BossGroup 处理连接请求
             *   WorkerGroup 处理业务逻辑
             * 3.两个都是无限循环
             */
            EventLoopGroup bossGroup = new NioEventLoopGroup(1);
            EventLoopGroup workerGroup = new NioEventLoopGroup();
    
            try {
        
                //创建服务端的启动对象 配置参数
                ServerBootstrap bootstrap = new ServerBootstrap();
    
                //使用链式编程进行设置
                /**
                 * 1.设置两个线程组
                 * 2.使用 NioSocketChannel 作为服务器的通道实现
                 * 3.设置线程队列得到的连接数
                 * 4.设置保持活动连接状态
                 * 5.给我们的 WorkerGroup 的 EventLoop 对应的管道设置处理器
                 */
                bootstrap.group(bossGroup,workerGroup)
                        .channel(NioServerSocketChannel.class)
                        .option(ChannelOption.SO_BACKLOG,128)
                        .childOption(ChannelOption.SO_KEEPALIVE,true)
                        .childHandler(new ChannelInitializer<SocketChannel>() {
        
                            //给 PipLine 设置处理器
                            @Override
                            protected void initChannel(SocketChannel socketChannel) throws Exception {
        
                                socketChannel.pipeline().addLast(new NettyServerHandler());
                            }
                        });
    
                System.out.println("Server is Ready");
    
                //绑定一个端口并且同步 生成了一个 ChannelFuture 对象 启动服务
                ChannelFuture cf = bootstrap.bind(6668).sync();
    
                System.out.println(123);
                cf.addListener(future->{
        
                    if (future.isSuccess()){
        
                        System.out.println("Server Bind Port Success");
                    }else {
        
                        System.out.println("Server Bind Port Fail");
                    }
                });
                System.out.println(456);
                //对关闭通道进行侦听
                cf.channel().closeFuture().sync();
            }finally {
        
                bossGroup.shutdownGracefully();
                workerGroup.shutdownGracefully();
            }
        }
    }

### 2.启动服务 ###

#### 1.启动日志 ####

Connected to the target VM, address: '127.0.0.1:64839', transport: 'socket'
    Java HotSpot(TM) 64-Bit Server VM warning: Sharing is only supported for boot loader classes because bootstrap classpath has been appended
    Server is Ready
    123
    456
    Server Bind Port Success

#### 2.结果分析 ####

在端口绑定完成后执行，即打印在456后面