java网络编程使用tcp、udp实现多用户对话

package com.just.im.server; import io.netty.channel.ChannelHandler; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandler; import io.netty.channel.socket.SocketChannel; import io.netty.util.internal.PlatformDependent; import java.util.concurrent.ConcurrentMap; /** * Created by bruce on 2023/1/6. */ @ChannelHandler.Sharable public class ServerHandler implements ChannelInboundHandler { private static ConcurrentMap<String,ChannelHandlerContext> channelConcurrentMap = PlatformDependent.newConcurrentHashMap(); @Override public void channelRegistered(ChannelHandlerContext channelHandlerContext) throws Exception { } @Override public void channelUnregistered(ChannelHandlerContext channelHandlerContext) throws Exception { } @Override public void channelActive(ChannelHandlerContext channelHandlerContext) throws Exception { String hostString = ((SocketChannel)channelHandlerContext.channel()).remoteAddress().getHostString(); System.out.println(hostString + " online"); channelConcurrentMap.put(hostString,channelHandlerContext); } @Override public void channelInactive(ChannelHandlerContext channelHandlerContext) throws Exception { } @Override public void channelRead(ChannelHandlerContext channelHandlerContext, Object o) throws Exception { System.out.println("ServerHandler channelRead...."); String messageString = o.toString(); String[] messages = messageString.split("@"); String message = messages[0]; String targetHost = messages[1]; System.out.println(channelHandlerContext.channel().remoteAddress()+"->Server :"+o.toString()); ChannelHandlerContext targetChannelHandlerContext = channelConcurrentMap.get(targetHost); targetChannelHandlerContext.write(channelHandlerContext.channel().remoteAddress() + " say : " + message); targetChannelHandlerContext.flush(); } @Override public void channelReadComplete(ChannelHandlerContext channelHandlerContext) throws Exception { } @Override public void userEventTriggered(ChannelHandlerContext channelHandlerContext, Object o) throws Exception { } @Override public void channelWritabilityChanged(ChannelHandlerContext channelHandlerContext) throws Exception { } @Override public void handlerAdded(ChannelHandlerContext channelHandlerContext) throws Exception { } @Override public void handlerRemoved(ChannelHandlerContext channelHandlerContext) throws Exception { } @Override public void exceptionCaught(ChannelHandlerContext channelHandlerContext, Throwable throwable) throws Exception { } }