应用程序代码

官方demo

/* * Copyright 2012 The Netty Project * * The Netty Project licenses this file to you under the Apache License, * version 2.0 (the "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at: * *   http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. */package io.netty.example.echo;import io.netty.bootstrap.Bootstrap;import io.netty.channel.ChannelFuture;import io.netty.channel.ChannelInitializer;import io.netty.channel.ChannelOption;import io.netty.channel.ChannelPipeline;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 io.netty.handler.ssl.SslContext;import io.netty.handler.ssl.SslContextBuilder;import io.netty.handler.ssl.util.InsecureTrustManagerFactory;/** * Sends one message when a connection is open and echoes back any received * data to the server.  Simply put, the echo client initiates the ping-pong * traffic between the echo client and server by sending the first message to * the server. */public final class EchoClient {    static final boolean SSL = System.getProperty("ssl") != null;    static final String HOST = System.getProperty("host", "127.0.0.1");    static final int PORT = Integer.parseInt(System.getProperty("port", "8007"));    static final int SIZE = Integer.parseInt(System.getProperty("size", "256"));    public static void main(String[] args) throws Exception {        // Configure SSL.git        final SslContext sslCtx;        if (SSL) {            sslCtx = SslContextBuilder.forClient()                .trustManager(InsecureTrustManagerFactory.INSTANCE).build();        } else {            sslCtx = null;        }        // Configure the client.        EventLoopGroup group = new NioEventLoopGroup();        try {            Bootstrap b = new Bootstrap();            b.group(group)             .channel(NioSocketChannel.class) //设置通道类 只是设置了通道对象 啥没没做             .option(ChannelOption.TCP_NODELAY, true)             .handler(new ChannelInitializer
    
     () {                 @Override                 public void initChannel(SocketChannel ch) throws Exception {                     ChannelPipeline p = ch.pipeline();                     if (sslCtx != null) {                         p.addLast(sslCtx.newHandler(ch.alloc(), HOST, PORT));                     }                     //p.addLast(new LoggingHandler(LogLevel.INFO));                     p.addLast(new EchoClientHandler());                 }             });            // Start the client.            ChannelFuture f = b.connect(HOST, PORT).sync();            // Wait until the connection is closed.            f.channel().closeFuture().sync();        } finally {            // Shut down the event loop to terminate all threads.            group.shutdownGracefully();        }    }}复制代码

netty源码

public abstract class AbstractBootstrap, C extends Channel> implements Cloneable {/**     * The {@link Class} which is used to create {@link Channel} instances from.     * You either use this or {@link #channelFactory(io.netty.channel.ChannelFactory)} if your     * {@link Channel} implementation has no no-args constructor.     */    public B channel(Class
      channelClass) {        if (channelClass == null) {            throw new NullPointerException("channelClass");        }        return channelFactory(new ReflectiveChannelFactory
     
      (channelClass)); //?    } /**     * @deprecated Use {@link #channelFactory(io.netty.channel.ChannelFactory)} instead.     */    @Deprecated    public B channelFactory(ChannelFactory
       channelFactory) {        if (channelFactory == null) {            throw new NullPointerException("channelFactory");        }        if (this.channelFactory != null) {            throw new IllegalStateException("channelFactory set already");        }        this.channelFactory = channelFactory; //主要是设置通道工厂类        return self();    }@SuppressWarnings("unchecked")    private B self() {        return (B) this; //返回值就是启动类本身    }复制代码

和nio channel区别？

一样封装了一下nio

通道channel到底指什么?

java网络通信有2套机制

1.java.net.socket

2.java.nio.channel

相同点都是表示一个连接服务器和客户端的连接但是网络编程里并不真正存在连接这个对象 jdbc里存在连接对象

不同点首先 1.它们是互相独立的之间没有任何关系是java网络通信的2套解决方案 2.1是同步阻塞 2是异步非阻塞异步非阻塞可以提高网络通信的性能就是不要一直卡在那里等在那里等就是浪费时间异步就是连接之间互不影响自己干自己的事情