TelnetServerHandler.java

/**        
 * Copyright (c) 2013 by 苏州科大国创信息技术有限公司.    
 */    
package com.ustcinfo.netty.telnet;

import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

import java.net.InetAddress;
import java.util.Date;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Create on @2013-8-24 @上午10:05:25 
 * @author bsli@ustcinfo.com
 */
public class TelnetServerHandler extends SimpleChannelInboundHandler<String> {

    private static final Logger logger = Logger.getLogger(TelnetServerHandler.class.getName());

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        // Send greeting for a new connection.
        ctx.write(
                "Welcome to " + InetAddress.getLocalHost().getHostName() + "!\r\n");
        ctx.write("It is " + new Date() + " now.\r\n");
        ctx.flush();
    }

    @Override
    public void channelRead0(ChannelHandlerContext ctx, String request) throws Exception {

        // Generate and write a response.
        String response;
        boolean close = false;
        if (request.isEmpty()) {
            response = "Please type something.\r\n";
        } else if ("bye".equals(request.toLowerCase())) {
            response = "Have a good day!\r\n";
            close = true;
        } else {
            response = "Did you say '" + request + "'?\r\n";
        }

        // We do not need to write a ChannelBuffer here.
        // We know the encoder inserted at TelnetPipelineFactory will do the conversion.
        ChannelFuture future = ctx.write(response);

        // Close the connection after sending 'Have a good day!'
        // if the client has sent 'bye'.
        if (close) {
            future.addListener(ChannelFutureListener.CLOSE);
        }
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        logger.log(
                Level.WARNING,
                "Unexpected exception from downstream.", cause);
        ctx.close();
    }
}