客户端连接服务器后服务器显示客户端上线,客户端断开服务器连接后服务器显示客户端下线,客户端发送一条消息,服务器和其他客户端都能接收到消息。
基本框架依然与第一个Echo程序相同,服务器与客户端都包含三部分代码。
MyChatServer
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
/**
* @author kun
*/
public class MyServer {
public static void main(String[] args) {
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new MyServerInitializer());
ChannelFuture channelFuture = serverBootstrap.bind(8899).sync();
channelFuture.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
MyChatServerInitializer
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.Delimiters;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.util.CharsetUtil;
/**
* @author kun
*/
public class MyServerInitializer extends ChannelInitializer<SocketChannel> {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
# 将特殊的分隔符作为消息分隔符,回车换行符是他的一种
pipeline.addLast(new DelimiterBasedFrameDecoder(4096, Delimiters.lineDelimiter()));
pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));
pipeline.addLast(new MyServerHandler());
}
}
MyChatServerHandler
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 kun
*/
public class MyServerHandler extends SimpleChannelInboundHandler<String> {
# 记录已经连接到服务器的通道,用来广播
private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
@Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
Channel channel = ctx.channel();
channelGroup.forEach(ch->{
if (channel!=ch){
ch.writeAndFlush(channel.remoteAddress()+"发送消息:"+msg+"\n");
}else {
ch.writeAndFlush("[自己]"+msg+"\n");
}
});
System.out.println(msg);
}
# 在ChannelHandler添加到ChannelPipeline时触发
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
channelGroup.writeAndFlush("[服务器]-"+channel.remoteAddress()+"加入\n");
channelGroup.add(channel);
}
# ChannelHandler从ChannelPipeline中被删除的时候触发
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
channelGroup.writeAndFlush("[服务器]-"+channel.remoteAddress()+"离开\n");
System.out.println("剩余客户端:"+channelGroup.size());
}
# 通道开启时触发
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
System.out.println(channel.remoteAddress()+"上线");
}
# 通道关闭时触发
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
System.out.println(channel.remoteAddress()+"下线");
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
ctx.close();
}
}
MyChatClient
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
/**
* @author kun
*/
public class MyClient {
public static void main(String[] args) {
EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(eventLoopGroup)
.channel(NioSocketChannel.class)
.handler(new MyClientInitializer());
Channel channel = bootstrap.connect("localhost", 8899).sync().channel();
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
# 死循环,将命令行的输入发送到服务器
for (;;){
channel.writeAndFlush(br.readLine()+"\r\n");
}
} catch (InterruptedException | IOException e) {
e.printStackTrace();
}finally {
eventLoopGroup.shutdownGracefully();
}
}
}
MyChatClientInitializer
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.Delimiters;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.util.CharsetUtil;
/**
* @author kun
*/
public class MyClientInitializer extends ChannelInitializer<SocketChannel> {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(new DelimiterBasedFrameDecoder(4096, Delimiters.lineDelimiter()));
pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));
pipeline.addLast(new MyClientHandler());
}
}
MyChatClientHandler
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
/**
* @author kun
*/
public class MyClientHandler extends SimpleChannelInboundHandler<String> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
System.out.println(msg);
}
}
服务器结果
先开启服务端,再一次开启三个客户端
客户端1
客户端2
客户端3
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