Netty之入门程序编写指南

电玩女神 2022-05-15 02:21 280阅读 0赞

# 一、环境搭建 #

netty的环境需要JDK1.6版本以上，以及对应的对应netty包，这里我使用的是maven管理项目，所以只需要引入对应的依赖就行了。

<dependency>
                <groupId>io.netty</groupId>
                <artifactId>netty-all</artifactId>
                <version>5.0.0.Alpha1</version>
            </dependency>

# 二、netty通信步骤 #

1.  创建两个的NIO线程组，一个专门用于网络事件处理(接受客户端的连接),另一个则进行网络通信读写。
2.  创建一个ServerBootStrap对象，配置netty的一系列对象，例如传出数据的缓存大小等等。
3.  创建一个实际处理数据的类Channellnitializer，进行初始化的准备工作，比如设置接受传出参数的字符集、格式，已经实际处理数据的接口
4.  绑定端口，执行同步阻塞方法等待服务端就编写完后了，此简单的四个步骤，我们的服务器端就编写完成了，几十行的代码就可以把他完成的健壮、性能稳定。

# 三、代码实现 #

server.java

package com.bee.springboot.netty.helloworld;
    
    
    import io.netty.bootstrap.ServerBootstrap;
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelInitializer;
    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: 服务器端
     * @author: maoqichuan
     * @date 2018/8/23  11:47
     */
    public class Server {
    	public static void main(String args[]) throws InterruptedException {
    		//1 第一个线程组 是用于接收Client端连接的
    		EventLoopGroup bossGroup = new NioEventLoopGroup();
    		//2 第二个线程组 是用于实际的业务处理操作的
    		EventLoopGroup workerGroup = new NioEventLoopGroup();
    
    		//3 创建一个辅助类Bootstrap，就是对我们的Server进行一系列的配置
    		ServerBootstrap b = new ServerBootstrap();
    		//把俩个工作线程组加入进来
    		b.group(bossGroup, workerGroup)
    				//我要指定使用NioServerSocketChannel这种类型的通道
    				.channel(NioServerSocketChannel.class)
    				//一定要使用 childHandler 去绑定具体的 事件处理器
    				.childHandler(new ChannelInitializer<SocketChannel>() {
    					@Override
    					protected void initChannel(SocketChannel sc) throws Exception {
    						sc.pipeline().addLast(new ServerHandler());
    					}
    				});
    
    		//绑定指定的端口 进行监听
    		ChannelFuture f = b.bind(8765).sync();
    
    		//Thread.sleep(1000000);
    		f.channel().closeFuture().sync();
    
    		bossGroup.shutdownGracefully();
    		workerGroup.shutdownGracefully();
    	}
    }

ServerHandler.java

package com.bee.springboot.netty.helloworld;
    
    
    import io.netty.buffer.ByteBuf;
    import io.netty.buffer.Unpooled;
    import io.netty.channel.ChannelHandlerAdapter;
    import io.netty.channel.ChannelHandlerContext;
    
    /**
     * @Description: 服务端事件处理器
     * @author: maoqichuan
     * @date 2018/8/23  9:46
     */
    public class ServerHandler extends ChannelHandlerAdapter{
    	@Override
    	public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
    		//do something msg
    		ByteBuf buf = (ByteBuf)msg;
    		byte[] data = new byte[buf.readableBytes()];
    		buf.readBytes(data);
    		String request = new String(data, "utf-8");
    		System.out.println("Server: " + request);
    		//写给客户端
    		String response = "我是反馈的信息";
    		ctx.writeAndFlush(Unpooled.copiedBuffer("888".getBytes()));
    		//.addListener(ChannelFutureListener.CLOSE);
    	}
    
    	@Override
    	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
    		cause.printStackTrace();
    		ctx.close();
    	}
    }

Client.java

package com.bee.springboot.netty.helloworld;
    
    import io.netty.bootstrap.Bootstrap;
    import io.netty.buffer.Unpooled;
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelInitializer;
    import io.netty.channel.EventLoopGroup;
    import io.netty.channel.nio.NioEventLoopGroup;
    import io.netty.channel.socket.SocketChannel;
    import io.netty.channel.socket.nio.NioSocketChannel;
    
    
    /**
     * @Description: 客户端
     * @author: maoqichuan
     * @date 2018/8/23  13:52
     */
    public class Client {
    
    	public static void main(String args[]) throws InterruptedException {
    		EventLoopGroup workgroup = new NioEventLoopGroup();
    		Bootstrap b = new Bootstrap();
    		b.group(workgroup);
    		b.channel(NioSocketChannel.class);
    		b.handler(new ChannelInitializer<SocketChannel>() {
    			@Override
    			protected void initChannel(SocketChannel sc) throws Exception {
    				sc.pipeline().addLast(new ClientHandler());
    			}
    		});
    
    		ChannelFuture cf1 = b.connect("127.0.0.1", 8765).sync();
    
    		//buf
    		cf1.channel().writeAndFlush(Unpooled.copiedBuffer("777".getBytes()));
    
    		cf1.channel().closeFuture().sync();
    		workgroup.shutdownGracefully();
    	}
    }

ClientHandler.java

package com.bee.springboot.netty.helloworld;
    
    import io.netty.buffer.ByteBuf;
    import io.netty.channel.ChannelHandlerAdapter;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.util.ReferenceCountUtil;
    
    /**
     * @Description: 客户端事件处理
     * @author: maoqichuan
     * @date 2018/8/23  13:57
     */
    public class ClientHandler extends ChannelHandlerAdapter {
    	@Override
    	public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
    		try {
    			//do something msg
    			ByteBuf buf = (ByteBuf)msg;
    			byte[] data = new byte[buf.readableBytes()];
    			buf.readBytes(data);
    			String request = new String(data, "utf-8");
    			System.out.println("Client: " + request);
    		} finally {
    			ReferenceCountUtil.release(msg);
    		}
    	}
    
    	@Override
    	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
    		cause.printStackTrace();
    		ctx.close();
    	}
    }