Netty 示例代码注解
Netty 的SampleCode，下面对代码进行一些必要的注解。
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1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.example.echo;
17
18 import io.netty.bootstrap.ServerBootstrap;
19 import io.netty.channel.ChannelFuture;
20 import io.netty.channel.ChannelInitializer;
21 import io.netty.channel.ChannelOption;
22 import io.netty.channel.ChannelPipeline;
23 import io.netty.channel.EventLoopGroup;
24 import io.netty.channel.nio.NioEventLoopGroup;
25 import io.netty.channel.socket.SocketChannel;
26 import io.netty.channel.socket.nio.NioServerSocketChannel;
27 import io.netty.handler.logging.LogLevel;
28 import io.netty.handler.logging.LoggingHandler;
29 import io.netty.handler.ssl.SslContext;
30 import io.netty.handler.ssl.SslContextBuilder;
31 import io.netty.handler.ssl.util.SelfSignedCertificate;
32
33 /**
34 * Echoes back any received data from a client.
35 */
/*
*Netty 对NIO进行了怎样的封装呢？
*/
36 public final class EchoServer {
37
38 static final boolean SSL = System.getProperty("ssl") != null;
39 static final int PORT = Integer.parseInt(System.getProperty("port", "8007"));
40
41 public static void main(String[] args) throws Exception {
42 // Configure SSL.
43 final SslContext sslCtx;
44 if (SSL) {
45 SelfSignedCertificate ssc = new SelfSignedCertificate();
46 sslCtx = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey()).build();
47 } else {
48 sslCtx = null;
49 }
50
51 // Configure the server.
//定义了两个用来处理IO事件的线程池，分别处理连接和数据的读写。bossGrop用来处理外部的连接请求， workerGroup用来处例数据的读取。
52 EventLoopGroup bossGroup = new NioEventLoopGroup(1);
53 EventLoopGroup workerGroup = new NioEventLoopGroup();
54 try {
//对ServerChannel的封装
//这里涉及到parent及child
//A parent channel is a channel which is supposed to accept incoming connections.
//It is created by this bootstrap's ChannelFactory via bind() and bind(SocketAddress).
//Once successfully bound, the parent channel starts to accept incoming connections, and the accepted connections become the children of the parent channel.
55 ServerBootstrap b = new ServerBootstrap();
56 b.group(bossGroup, workerGroup)
57 .channel(NioServerSocketChannel.class)
58 .option(ChannelOption.SO_BACKLOG, 100)//最多有几个请求排队
59 .handler(new LoggingHandler(LogLevel.INFO))
60 .childHandler(new ChannelInitializer() {//ChannelHandler 处理自己感兴趣的事件，ChannelPipeline为处理事件的容器，其实 //这里就是Netty事件驱动的实现。 //添加必要的Handler, 一般业务逻辑就要实现在这里面。
61 @Override
62 public void initChannel(SocketChannel ch) throws Exception {
63 ChannelPipeline p = ch.pipeline();
64 if (sslCtx != null) {
65 p.addLast(sslCtx.newHandler(ch.alloc()));
66 }
67 //p.addLast(new LoggingHandler(LogLevel.INFO));
68 p.addLast(new EchoServerHandler());
69 }
70 });
71
72 // Start the server.
73 ChannelFuture f = b.bind(PORT).sync();
74
75 // Wait until the server socket is closed.
76 f.channel().closeFuture().sync();
77 } finally {
78 // Shut down all event loops to terminate all threads.
79 bossGroup.shutdownGracefully();
80 workerGroup.shutdownGracefully();
81 }
82 }
83 }
This page was automatically generated by MavenView Javadoc
1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.example.echo;
17
18 import io.netty.channel.ChannelHandler.Sharable;
19 import io.netty.channel.ChannelHandlerContext;
20 import io.netty.channel.ChannelInboundHandlerAdapter;
21
22 /**
23 * Handler implementation for the echo server.
24 */
25 @Sharable
26 public class EchoServerHandler extends ChannelInboundHandlerAdapter {
27
//这个ctx是个什么概念呢？
28 @Override
29 public void channelRead(ChannelHandlerContext ctx, Object msg) {
30 ctx.write(msg);//把消息写入buffer中
31 }
32
33 @Override
34 public void channelReadComplete(ChannelHandlerContext ctx) {
35 ctx.flush();//刷新buffer
36 }
37
38 @Override
39 public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
40 // Close the connection when an exception is raised.
41 cause.printStackTrace();
42 ctx.close();
43 }
44 }
This page was automatically generated by Maven /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.example.echo;
17
18 import io.netty.bootstrap.Bootstrap;
19 import io.netty.channel.ChannelFuture;
20 import io.netty.channel.ChannelInitializer;
21 import io.netty.channel.ChannelOption;
22 import io.netty.channel.ChannelPipeline;
23 import io.netty.channel.EventLoopGroup;
24 import io.netty.channel.nio.NioEventLoopGroup;
25 import io.netty.channel.socket.SocketChannel;
26 import io.netty.channel.socket.nio.NioSocketChannel;
27 import io.netty.handler.ssl.SslContext;
28 import io.netty.handler.ssl.SslContextBuilder;
29 import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
30
31 /**
32 * Sends one message when a connection is open and echoes back any received
33 * data to the server. Simply put, the echo client initiates the ping-pong
34 * traffic between the echo client and server by sending the first message to
35 * the server.
36 */
37 public final class EchoClient {
38
39 static final boolean SSL = System.getProperty("ssl") != null;
40 static final String HOST = System.getProperty("host", "127.0.0.1");
41 static final int PORT = Integer.parseInt(System.getProperty("port", "8007"));
42 static final int SIZE = Integer.parseInt(System.getProperty("size", "256"));
43
44 public static void main(String[] args) throws Exception {
45 // Configure SSL.git
46 final SslContext sslCtx;
47 if (SSL) {
48 sslCtx = SslContextBuilder.forClient()
49 .trustManager(InsecureTrustManagerFactory.INSTANCE).build();
50 } else {
51 sslCtx = null;
52 }
53
54 // Configure the client.
55 EventLoopGroup group = new NioEventLoopGroup();
56 try {
57 Bootstrap b = new Bootstrap();
58 b.group(group)
59 .channel(NioSocketChannel.class)
60 .option(ChannelOption.TCP_NODELAY, true)
61 .handler(new ChannelInitializer() {
62 @Override
63 public void initChannel(SocketChannel ch) throws Exception {
64 ChannelPipeline p = ch.pipeline();
65 if (sslCtx != null) {
66 p.addLast(sslCtx.newHandler(ch.alloc(), HOST, PORT));
67 }
68 //p.addLast(new LoggingHandler(LogLevel.INFO));
69 p.addLast(new EchoClientHandler());
70 }
71 });
72
73 // Start the client.
74 ChannelFuture f = b.connect(HOST, PORT).sync();
75
76 // Wait until the connection is closed.
77 f.channel().closeFuture().sync();
78 } finally {
79 // Shut down the event loop to terminate all threads.
80 group.shutdownGracefully();
81 }
82 }
83 }