菜鳥Java使用Netty
阿新 • • 發佈：2019-01-26
下載下來，搜尋半天，如何使用Netty。。。。。。。。。。。網上找不到一篇類似的文章。對新手真是巨大的創傷啊！
還下載了Maven。現在還不知道這個東西幹嘛的。好像對我使用Natty一點幫助都沒有。
下載完，解壓至某指定目錄。
然後引入它的包即可
開啟兩個Eclipse
一個寫一個伺服器，一個寫一個客戶端
伺服器結果如下：
此四步用於引入Netty的包。
客戶端亦如此
EchoServer.java 程式碼為：
/* * 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 程式碼為：
/* * 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(); } }
客戶端
EchoClient.java 程式碼為：
/* * 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 程式碼為：
/*
* 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();
}
}執行結果：
伺服器啟動為Java Application型別，
客戶端啟動後，伺服器的反應：
http://blog.csdn.net/suifeng3051/article/details/25238243
這裡有一個形象的比喻來形容Netty客戶端和伺服器端的互動模式，
比如把你比作一個Client，把山比作一個Server，你走到山旁，就是和山建立了連結，
你向山大喊了一聲，就代表向山傳送了資料，你的喊聲經過山的反射形成了回聲，這個回聲就是伺服器的響應資料。如果你離開，就代表斷開了連結，當然你也可以再回來。
好多人可以同時向山大喊，他們的喊聲也一定會得到山的迴應。
官方文件：
http://netty.io/wiki/user-guide-for-4.x.html#wiki-h3-17
Netty4.x中文教程系列(一) 目錄及概述 - Tiny&zzh - 部落格園
[Android初級]android與netty4初體驗 - 消失的天空 - 部落格頻道 - CSDN.NET
http://blog.csdn.net/jan_s/article/details/43702569