基于netty的聊天室(保持和获取客户端channel)

package chatroom;

import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.util.concurrent.GlobalEventExecutor;

/**
* @Author: Usher
* @Description:
* 回调处理类,继承SimpleChannelInboundHandler处理出站入站数据，模板设计模式，让主要的处理逻辑保持不变，让变化的步骤通过接口实现来完成
*/
public class ChatServerHandler extends SimpleChannelInboundHandler <String>{

public static ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
/**
* 当有客户端连接时，handlerAdded会执行,就把该客户端的通道记录下来，加入队列
* @param ctx
* @throws Exception
*/
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
Channel inComing = ctx.channel();//获得客户端通道
//通知其他客户端有新人进入
for (Channel channel : channels){
if (channel != inComing)
channel.writeAndFlush("[欢迎: " + inComing.remoteAddress() + "] 进入聊天室！ ");
}

channels.add(inComing);//加入队列
}

/**
* 断开连接
* @param ctx
* @throws Exception
*/
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
Channel outComing = ctx.channel();//获得客户端通道
//通知其他客户端有人离开
for (Channel channel : channels){
if (channel != outComing)
channel.writeAndFlush("[再见: ]" + outComing.remoteAddress() + " 离开聊天室！ ");
}

channels.remove(outComing);
}

/**
* 每当从客户端有消息写入时
* @param channelHandlerContext
* @param s
* @throws Exception
*/
protected void channelRead0(ChannelHandlerContext channelHandlerContext, String s) throws Exception {
Channel inComing = channelHandlerContext.channel();

for (Channel channel : channels){
if (channel != inComing){
channel.writeAndFlush("[用户" + inComing.remoteAddress() + " 说：]" + s + " ");
}else {
channel.writeAndFlush("[我说：]" + s + " ");
}
}
}

/**
* 当服务器监听到客户端活动时
* @param ctx
* @throws Exception
*/
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
Channel inComing = ctx.channel();
System.out.println("[" + inComing.remoteAddress() + "]: 在线");
}

/**
* 离线
* @param ctx
* @throws Exception
*/
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
Channel inComing = ctx.channel();
System.out.println("[" + inComing.remoteAddress() + "]: 离线");
}

@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
Channel inComing = ctx.channel();
System.out.println(inComing.remoteAddress() + "通讯异常！");
ctx.close();
}
}
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版权声明：本文为CSDN博主「Usher_Ou」的原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/usher_ou/java/article/details/80919350