Netty:服务端给客户端发送消息后的异步回调

package cn.edu.tju.handler;

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

public class SuffixServerHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg){
        ByteBuf buf=(ByteBuf)msg;
        String result=buf.toString(CharsetUtil.UTF_8);
        System.out.println("_______________________________in suffix handler______________________");
        System.out.println("原始消息："+result);
        result+=":suffix";
        System.out.println("处理后的消息："+result);
        System.out.println("_______________________________in suffix handler______________________");
        ByteBuf sendingBuff = Unpooled.copiedBuffer("this is response data.", CharsetUtil.UTF_8);
        ChannelFuture channelFuture = ctx.writeAndFlush(sendingBuff);
        channelFuture.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture channelFuture) throws Exception {
                System.out.println("发送完成");

            }
        });



    }
}