Netty学习

1.Dependency:

<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.0.CR7</version>
</dependency>

2.单服务器,多客户端例子:

2.1.创建一个消息处理的Handler,它继承ChannelInboundHandlerAdapter

package leo.test;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;

/**
* @author Leo
* @date 2016年4月25日下午2:41:52
* @description
* @usage
*/
public class MsgHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) { // (2)
ByteBuf in = (ByteBuf) msg;//接收
ByteBuf out = ctx.alloc().buffer();//发送
System.out.println("Rcv:" + in.toString(CharsetUtil.UTF_8));//打印接收到的消息
out.writeBytes("Server have rcv the msg.".getBytes(CharsetUtil.UTF_8));//将要发送的消息以byte形式存在out中
ctx.writeAndFlush(out);//通过ctx输出到接收端.
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { // (4)
// Close the connection when an exception is raised.
cause.printStackTrace();
ctx.close();
}
}

2.2.根据官网的demo创建一个Server
package leo.test;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;

/**
* @author Leo
* @date 2016年4月25日下午2:43:49
* @description
* @usage
*/
public class Server {
private int port;

public Server(int port) {
this.port = port;
}

public void run() throws Exception {
EventLoopGroup bossGroup = new NioEventLoopGroup(); // (1)
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap(); // (2)
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class) // (3)
.childHandler(new ChannelInitializer<SocketChannel>() { // (4)
@Override
public void initChannel(SocketChannel ch)
throws Exception {
ch.pipeline().addLast(new MsgHandler());
}
}).option(ChannelOption.SO_BACKLOG, 128) // (5)
.childOption(ChannelOption.SO_KEEPALIVE, true); // (6)

// Bind and start to accept incoming connections.
ChannelFuture f = b.bind(port).sync(); // (7)

// Wait until the server socket is closed.
// In this example, this does not happen, but you can do that to
// gracefully
// shut down your server.
f.channel().closeFuture().sync();
} finally {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
}
}

}


2.3.测试:
2.3.1.先启动server

package leo.test;

import org.junit.Test;

/**
* @author Leo
* @date 2016年4月26日上午9:29:16
* @description
* @usage
*/
public class MyTest {
@Test
public void test01() {
try {
new Server(9527).run();//port number:9527
} catch (Exception e) {
e.printStackTrace();
}
}
}

2.3.2.如果是在window下,你可以很方便的用telnet进行测试.

2.3.2.1.进入cmd

2.3.2.2.输入    telnet localhost 9527
2.3.2.3.随便输入点东西,就可以看到客户端与服务器的交互了.

参考资料:http://netty.io/wiki/user-guide-for-4.x.html