Netty中的session属性设置和链接事件捕获

Netty中的session属性设置和链接事件捕获

Netty的使用比mina更灵活，也更复杂，下面通过一个例子，主要说明netty中如何对某个链接设置属性，并顺带描述了链接事件的捕获。

 

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
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;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;
import io.netty.handler.timeout.IdleStateHandler;
import io.netty.util.AttributeKey;

public class NettyAttrTest {

	public static void main(String[] args) throws InterruptedException {
	    EventLoopGroup bossGroup = new NioEventLoopGroup(); 
	    EventLoopGroup workerGroup = new NioEventLoopGroup();
	    try {
	        ServerBootstrap b = new ServerBootstrap();
	        b.group(bossGroup, workerGroup)
	         .channel(NioServerSocketChannel.class)
	         .childHandler(new ChannelInitializer() {
	        	private static final int IDEL_TIME_OUT = 10;
	            private static final int READ_IDEL_TIME_OUT = 4;
	        	private static final int WRITE_IDEL_TIME_OUT = 5;
	        	private AttributeKey START_TIME = new AttributeKey("START_TIME");
	             @Override
	             public void initChannel(SocketChannel ch) throws Exception {
	            	 //idle事件监听
	         		ch.pipeline().addLast("idleStateHandler", new IdleStateHandler(READ_IDEL_TIME_OUT, WRITE_IDEL_TIME_OUT, IDEL_TIME_OUT));
	                ch.pipeline().addLast(new ChannelInboundHandlerAdapter(){
	                	
	                	@Override
	                	public void channelRegistered(ChannelHandlerContext ctx)//链接事件监听
	                			throws Exception {
	                		System.out.println("channel register");
	                		//设置链接属性，记录链接开始的时间
	                		ctx.attr(START_TIME).set(System.currentTimeMillis());
	                	}
	                	
	                	@Override
	                	public void channelUnregistered(//断开链接事件
	                			ChannelHandlerContext ctx) throws Exception {
	                		System.out.println("channel unregister");
	                	}
	                	
	                	@Override
	                	public void userEventTriggered(//事件监听
	                			ChannelHandlerContext ctx, Object evt)
	                			throws Exception {
	                		//监听idle事件
	                		if(IdleStateEvent.class.isAssignableFrom(evt.getClass())){
	                			IdleStateEvent event = (IdleStateEvent) evt;
	                			//获取链接相关的属性（即链接开始的时间戳）
	                			Long startTime = ctx.attr(START_TIME).get();
	                			if(startTime == null)
	                				//not arrive forever
	                				return;
	                			//read idle
	                			if(event.state() == IdleState.READER_IDLE)
	                				System.out.println("read idle"+startTime);
	                			//write idle
	                			else if(event.state() == IdleState.WRITER_IDLE)
	                				System.out.println("write idle"+startTime);
	                			//read and write idle
	                			else if(event.state() == IdleState.ALL_IDLE)
	                				System.out.println("all idle"+startTime);
	                		}
	                	}
	                });
	             }
	         })
	         .option(ChannelOption.SO_BACKLOG, 128)
	         .childOption(ChannelOption.SO_KEEPALIVE, true);
	        
	        ChannelFuture f = b.bind(8080).sync();
	        f.channel().closeFuture().sync();
	    } finally {
	        workerGroup.shutdownGracefully();
	        bossGroup.shutdownGracefully();
	    }
	}
	
	
}

channelRegistered用于监听链接事件，当客户端链接时，将链接的时间记录在ctx的attr中。

 userEventTriggered中针对某一个特定的链接取出其链接时间，并输出出来。

测试：开启两个telnet客户端：

telnet 127.0.0.1 8080

结果：

channel register

channel register

read idle1378195113609

write idle1378195113609

read idle1378195117015

read idle1378195113609

write idle1378195117015

all idle1378195113609

write idle1378195113609

read idle1378195117015

read idle1378195113609

all idle1378195117015

write idle1378195117015