Netty 4.0 demo
netty是一个异步，事件驱动的网络编程框架&工具，使用netty，可以快速开发从可维护，高性能的协议服务和客户端应用。是一个继mina之后，一个非常受欢迎的nio网络框架
netty4.x和之前的版本变化很大，包结构、对象和之前有很大不同。原来的包结构都是org.jboss.netty.*；目前改为了io.netty.* 的方式，其中，server，client的对象也和原来不同了
根据4.x的稳定版本4.0.14为蓝本，写一个hello world试试看。值得注意的是，4.0.x的beta版和final版本也有不小调整。很不幸的时，在4.x中刚出现的部分方法，到5.x中也将废弃。哎，苦逼的IT人。废话不说，看个4.x的例子吧
需要说明的是，我用的是netty4.0.13这个版本。因为netty有很多包，大家可以引入这个all包，其他的就全部包括了。
server端代码：
1 package netty.test;
2
3
4 import io.netty.bootstrap.ServerBootstrap;
5 import io.netty.channel.Channel;
6 import io.netty.channel.ChannelFuture;
7 import io.netty.channel.ChannelInitializer;
8 import io.netty.channel.ChannelPipeline;
9 import io.netty.channel.EventLoopGroup;
10 import io.netty.channel.nio.NioEventLoopGroup;
11 import io.netty.channel.socket.nio.NioServerSocketChannel;
12 import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
13 import io.netty.handler.codec.LengthFieldPrepender;
14 import io.netty.handler.codec.string.StringDecoder;
15 import io.netty.handler.codec.string.StringEncoder;
16 import io.netty.util.CharsetUtil;
17
18 public class MyNettyServer {
19 private static final String IP = "127.0.0.1";
20 private static final int PORT = 5656;
21 private static final int BIZGROUPSIZE = Runtime.getRuntime().availableProcessors()*2;
22
23 private static final int BIZTHREADSIZE = 100;
24 private static final EventLoopGroup bossGroup = new NioEventLoopGroup(BIZGROUPSIZE);
25 private static final EventLoopGroup workerGroup = new NioEventLoopGroup(BIZTHREADSIZE);
26 public static void service() throws Exception {
27 ServerBootstrap bootstrap = new ServerBootstrap();
28 bootstrap.group(bossGroup, workerGroup);
29 bootstrap.channel(NioServerSocketChannel.class);
30 bootstrap.childHandler(new ChannelInitializer<Channel>() {
31
32 @Override
33 protected void initChannel(Channel ch) throws Exception {
34 // TODO Auto-generated method stub
35 ChannelPipeline pipeline = ch.pipeline();
36 pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4, 0, 4));
37 pipeline.addLast(new LengthFieldPrepender(4));
38 pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
39 pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));
40 pipeline.addLast(new TcpServerHandler());
41 }
42
43 });
44 ChannelFuture f = bootstrap.bind(IP, PORT).sync();
45 f.channel().closeFuture().sync();
46 System.out.println("TCP服务器已启动");
47 }
48
49 protected static void shutdown() {
50 workerGroup.shutdownGracefully();
51 bossGroup.shutdownGracefully();
52 }
53
54 public static void main(String[] args) throws Exception {
55 System.out.println("开始启动TCP服务器...");
56 MyNettyServer.service();
57 // HelloServer.shutdown();
58 }
59 }
对应的Handler对象 TcpServerHandler.java
1 package netty.test;
2
3 import io.netty.channel.ChannelHandlerAdapter;
4 import io.netty.channel.ChannelHandlerContext;
5 import io.netty.channel.ChannelInboundHandlerAdapter;
6
7 public class TcpServerHandler extends ChannelInboundHandlerAdapter {
8
9
10 @Override
11 public void channelRead(ChannelHandlerContext ctx, Object msg)
12 throws Exception {
13 // TODO Auto-generated method stub
14 System.out.println("server receive message :"+ msg);
15 ctx.channel().writeAndFlush("yes server already accept your message" + msg);
16 ctx.close();
17 }
18 @Override
19 public void channelActive(ChannelHandlerContext ctx) throws Exception {
20 // TODO Auto-generated method stub
21 System.out.println("channelActive>>>>>>>>");
22 }
23 @Override
24 public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
25 System.out.println("exception is general");
26 }
27 }
客户端代码：
1 package netty.test;
2
3 import io.netty.bootstrap.Bootstrap;
4 import io.netty.channel.ChannelFuture;
5 import io.netty.channel.ChannelInitializer;
6 import io.netty.channel.ChannelOption;
7 import io.netty.channel.ChannelPipeline;
8 import io.netty.channel.EventLoopGroup;
9 import io.netty.channel.nio.NioEventLoopGroup;
10 import io.netty.channel.socket.SocketChannel;
11 import io.netty.channel.socket.nio.NioSocketChannel;
12 import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
13 import io.netty.handler.codec.LengthFieldPrepender;
14 import io.netty.handler.codec.string.StringDecoder;
15 import io.netty.handler.codec.string.StringEncoder;
16 import io.netty.util.CharsetUtil;
17
18 public class NettyClient implements Runnable {
19
20 @Override
21 public void run() {
22 EventLoopGroup group = new NioEventLoopGroup();
23 try {
24 Bootstrap b = new Bootstrap();
25 b.group(group);
26 b.channel(NioSocketChannel.class).option(ChannelOption.TCP_NODELAY, true);
27 b.handler(new ChannelInitializer<SocketChannel>() {
28 @Override
29 protected void initChannel(SocketChannel ch) throws Exception {
30 ChannelPipeline pipeline = ch.pipeline();
31 pipeline.addLast("frameDecoder", new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4, 0, 4));
32 pipeline.addLast("frameEncoder", new LengthFieldPrepender(4));
33 pipeline.addLast("decoder", new StringDecoder(CharsetUtil.UTF_8));
34 pipeline.addLast("encoder", new StringEncoder(CharsetUtil.UTF_8));
35
36 pipeline.addLast("handler", new HelloClient());
37 }
38 });
39 for (int i = 0; i < 100000; i++) {
40 ChannelFuture f = b.connect("127.0.0.1", 5656).sync();
41 f.channel().writeAndFlush("hello Service!"+Thread.currentThread().getName()+":--->:"+i);
42 f.channel().closeFuture().sync();
43 }
44
45
46 } catch (Exception e) {
47
48 } finally {
49 group.shutdownGracefully();
50 }
51 }
52
53 public static void main(String[] args) throws Exception {
54 for (int i = 0; i < 1000; i++) {
55 new Thread(new NettyClient(),">>>this thread "+i).start();
56 }
57 }
58 }
客户端对应的Handler对象代码，HelloClient.java
package netty.test; import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter; public class HelloClient extends ChannelInboundHandlerAdapter {
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
System.out.println("client接收到服务器返回的消息:" + msg);
} @Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
System.out.println("client exception is general");
}
}