菜鸟Java使用Netty

下载下来，搜索半天，如何使用Netty。。。。。。。。。。。网上找不到一篇类似的文章。对新手真是巨大的创伤啊！

还下载了Maven。现在还不知道这个东西干嘛的。好像对我使用Natty一点帮助都没有。

下载完，解压至某指定目录。

然后引入它的包即可

打开两个Eclipse

一个写一个服务器，一个写一个客户端 

服务器结果如下：

此四步用于引入Netty的包。

客户端亦如此

EchoServer.java 代码为：

/*
 * 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 netty.echo.handler;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelHandler.Sharable;

@Sharable
public class EchoServerHandler extends ChannelInboundHandlerAdapter {
	
	@Override
	public void channelActive(ChannelHandlerContext ctx) {
		System.out.println("channelActive!!!!!!!!!!!");
	}

	@Override
	public void channelRead(ChannelHandlerContext ctx, Object msg) {
		System.out.println("channelRead!!!!!!!!!!!!!!!!!!!!!!!");
		
		ByteBuf buf = (ByteBuf)msg;
		//System.out.println(buf.);
		ctx.write(msg);
	}

	@Override
	public void channelReadComplete(ChannelHandlerContext ctx) {
		ctx.flush();
	}

	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
		// Close the connection when an exception is raised.
		cause.printStackTrace();
		ctx.close();
	}
}

EchoServerHandler.java 代码为：

/*
 * 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 netty.echo.handler;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelHandler.Sharable;

@Sharable
public class EchoServerHandler extends ChannelInboundHandlerAdapter {
	
	@Override
	public void channelActive(ChannelHandlerContext ctx) {
		System.out.println("channelActive!!!!!!!!!!!");
	}

	@Override
	public void channelRead(ChannelHandlerContext ctx, Object msg) {
		System.out.println("channelRead!!!!!!!!!!!!!!!!!!!!!!!");
		
		ByteBuf buf = (ByteBuf)msg;
		//System.out.println(buf.);
		ctx.write(msg);
	}

	@Override
	public void channelReadComplete(ChannelHandlerContext ctx) {
		ctx.flush();
	}

	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
		// Close the connection when an exception is raised.
		cause.printStackTrace();
		ctx.close();
	}
}

             客户端               

EchoClient.java 代码为：

/*
 * 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 netty.echo.client;

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;

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 = null;

		// Configure the client.
		EventLoopGroup group = new NioEventLoopGroup();
		try {
			Bootstrap b = new Bootstrap();
			b.group(group).channel(NioSocketChannel.class).option(ChannelOption.TCP_NODELAY, true)
					.handler(new ChannelInitializer<SocketChannel>() {
						@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();
		}
	}
}

EchoClientHandler.java 代码为：

/*
 * 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 netty.echo.client;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;

/**
 * Handler implementation for the echo client.  It initiates the ping-pong
 * traffic between the echo client and server by sending the first message to
 * the server.
 */
public class EchoClientHandler extends ChannelInboundHandlerAdapter {

    private final ByteBuf firstMessage;

    /**
     * Creates a client-side handler.
     */
    public EchoClientHandler() {
        firstMessage = Unpooled.buffer(EchoClient.SIZE);
        for (int i = 0; i < firstMessage.capacity(); i ++) {
            firstMessage.writeByte((byte) i);
        }
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        //ctx.writeAndFlush(firstMessage);
    	String x = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
    	firstMessage.writeBytes(x.getBytes());
    	ctx.writeAndFlush(firstMessage);
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) {
        ctx.write(msg);
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) {
       ctx.flush();
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        // Close the connection when an exception is raised.
        cause.printStackTrace();
        ctx.close();
    }
}

运行结果：

服务器启动为Java Application类型，

客户端启动后，服务器的反应：

http://blog.csdn.net/suifeng3051/article/details/25238243

     这里有一个形象的比喻来形容Netty客户端和服务器端的交互模式，

比如把你比作一个Client，把山比作一个Server，你走到山旁，就是和山建立了链接，

你向山大喊了一声，就代表向山发送了数据，你的喊声经过山的反射形成了回声，这个回声就是服务器的响应数据。如果你离开，就代表断开了链接，当然你也可以再回来。

好多人可以同时向山大喊，他们的喊声也一定会得到山的回应。

官方文档：

http://netty.io/wiki/user-guide-for-4.x.html#wiki-h3-17

Netty4.x中文教程系列(一) 目录及概述 - Tiny&zzh - 博客园

 http://www.cnblogs.com/zou90512/p/3492287.html

[Android初级]android与netty4初体验 - 消失的天空 - 博客频道 - CSDN.NET

 http://blog.csdn.net/jan_s/article/details/43702569

Netty4详解三：Netty架构设计 - Heaven Wang 的专栏 - 博客频道 - CSDN.NET  http://blog.csdn.net/suifeng3051/article/details/28861883?utm_source=tuicool&utm_medium=referral Netty4详解