EchoServerV1Handler.java

package com.github.nettybook.ch4;

import java.nio.charset.Charset;

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

/**
 * Handler implementation for the echo server.
 */
public class EchoServerV1Handler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) {
        ByteBuf readMessage = (ByteBuf) msg;
        System.out.println("channelRead : " + readMessage.toString(Charset.defaultCharset()));
//        ctx.writeAndFlush(msg);
        ctx.write(msg);
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        ctx.close();
    }
}