netty学习三:基于socket的聊天小demo

服务端代码

package chat.server;

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;

public class ChatServer {

public static void main(String[] args) throws InterruptedException {
// 接收连接,但是不处理
EventLoopGroup parentGroup = new NioEventLoopGroup();
// 真正处理连接的group
EventLoopGroup childGroup = new NioEventLoopGroup();

try {
//加载Initializer
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(parentGroup, childGroup)
.channel(NioServerSocketChannel.class)
//这里的childHandler是服务于childGroup的,如果直接使用
//handler方法添加处理器,则是服务于parentGroup的
.childHandler(new ChatServerInitializer());

//绑定监听端口
ChannelFuture channelFuture = serverBootstrap.bind(8899).sync();
channelFuture.channel().closeFuture().sync();
}
finally {
parentGroup.shutdownGracefully();
childGroup.shutdownGracefully();
}
}
}

package chat.server;

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;

public class ChatServerInitializer extends ChannelInitializer<SocketChannel>{
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();

//1、按照分隔符切割消息
pipeline.addLast(new DelimiterBasedFrameDecoder(4096,Delimiters.lineDelimiter()));

//2、socket编程中需要对字符串进行编码解码
pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));

pipeline.addLast(new ChatServerHandler());
}
}

package chat.server;

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;

public class ChatServerHandler extends SimpleChannelInboundHandler<String>{
//存放所有channel对象
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()+" 发送的:"+msg+"\n");
}
else {
ch.writeAndFlush("本人发的消息:"+msg + "\n");
}
});
}

@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
channelGroup.writeAndFlush("有人:"+channel.remoteAddress()+"加入\n");

channelGroup.add(channel);
}

@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
channelGroup.writeAndFlush("有人:"+channel.remoteAddress()+"离开\n");
}

@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
System.out.println(channel.remoteAddress() + "上线");
}

@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
System.out.println(channel.remoteAddress() + "上线");
}

}

客户端代码

package chat.client;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

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;

public class ChatClient {

public static void main(String[] args) throws InterruptedException, IOException {
EventLoopGroup eventLoopGroup = new NioEventLoopGroup();

try {
//加载Initializer
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(eventLoopGroup)
.channel(NioSocketChannel.class)
.handler(new ChatClientInitializer());

//连接服务端
Channel channel = bootstrap.connect("localhost", 8899).sync().channel();
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
for(;;) {
channel.writeAndFlush(br.readLine() + "\r\n");
}
}
finally {
eventLoopGroup.shutdownGracefully();
}
}
}

package chat.client;

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;

public class ChatClientInitializer extends ChannelInitializer<SocketChannel>{
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
//1、按照分隔符切割消息
pipeline.addLast(new DelimiterBasedFrameDecoder(4096,Delimiters.lineDelimiter()));

//2、socket编程中需要对字符串进行编码解码
pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));

//3、添加自定义处理器
pipeline.addLast(new ChatClientHandler());
}
}

package chat.client;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

public class ChatClientHandler extends SimpleChannelInboundHandler<String>{
@Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
System.out.println(msg);
}
}

当有新的客户端连接到服务器的时候,ChatServerHandler的channelRead0方法会给所有上线的客户端发送消息。

ChatClient的main方法中,会从System.in中获取用户的输入,并写到服务端。

csdn code 路径

这个项目的源代码放置在csdn code上,欢迎访问。

netty_study