- 客户端
首先编写我们的服务端处理器 handler
public class SimpleChatServerHandler extends SimpleChannelInboundHandler { // (1)
public static ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception { // (2)
Channel incoming = ctx.channel();
// Broadcast a message to multiple Channels
channels.writeAndFlush("[SERVER] - " + incoming.remoteAddress() + " 加入\n");
channels.add(ctx.channel());
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception { // (3)
Channel incoming = ctx.channel();
// Broadcast a message to multiple Channels
channels.writeAndFlush("[SERVER] - " + incoming.remoteAddress() + " 离开\n");
// A closed Channel is automatically removed from ChannelGroup,
// so there is no need to do "channels.remove(ctx.channel());"
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, String s) throws Exception { // (4)
Channel incoming = ctx.channel();
for (Channel channel : channels) {
if (channel != incoming){
channel.writeAndFlush("[" + incoming.remoteAddress() + "]" + s + "\n");
} else {
channel.writeAndFlush("[you]" + s + "\n");
}
}
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception { // (5)
Channel incoming = ctx.channel();
System.out.println("SimpleChatClient:"+incoming.remoteAddress()+"在线");
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception { // (6)
Channel incoming = ctx.channel();
System.out.println("SimpleChatClient:"+incoming.remoteAddress()+"掉线");
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { // (7)
Channel incoming = ctx.channel();
System.out.println("SimpleChatClient:"+incoming.remoteAddress()+"异常");
// 当出现异常就关闭连接
cause.printStackTrace();
ctx.close();
}
}
服务端的初始化类
public class SimpleChatServerInitializer extends
ChannelInitializer {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast("framer", new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));
pipeline.addLast("decoder", new StringDecoder());
pipeline.addLast("encoder", new StringEncoder());
pipeline.addLast("handler", new SimpleChatServerHandler());
System.out.println("SimpleChatClient:"+ch.remoteAddress() +"连接上");
}
}
服务端
public class SimpleChatServer {
private int port;
public SimpleChatServer(int port) {
this.port = port;
}
public void run() throws Exception {
EventLoopGroup bossGroup = new NioEventLoopGroup(); // (1)
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap(); // (2)
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class) // (3)
.childHandler(new SimpleChatServerInitializer()) //(4)
.option(ChannelOption.SO_BACKLOG, 128) // (5)
.childOption(ChannelOption.SO_KEEPALIVE, true); // (6)
System.out.println("SimpleChatServer 启动了");
// 绑定端口，开始接收进来的连接
ChannelFuture f = b.bind(port).sync(); // (7)
// 等待服务器 socket 关闭 。
// 在这个例子中，这不会发生，但你可以优雅地关闭你的服务器。
f.channel().closeFuture().sync();
} finally {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
System.out.println("SimpleChatServer 关闭了");
}
}
public static void main(String[] args) throws Exception {
int port;
if (args.length > 0) {
port = Integer.parseInt(args[0]);
} else {
port = 8080;
}
new SimpleChatServer(port).run();
}
}
- 服务端
服务端处理器
public class SimpleChatServerHandler extends SimpleChannelInboundHandler { // (1)
public static ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception { // (2)
Channel incoming = ctx.channel();
// Broadcast a message to multiple Channels
channels.writeAndFlush("[SERVER] - " + incoming.remoteAddress() + " 加入\n");
channels.add(ctx.channel());
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception { // (3)
Channel incoming = ctx.channel();
// Broadcast a message to multiple Channels
channels.writeAndFlush("[SERVER] - " + incoming.remoteAddress() + " 离开\n");
// A closed Channel is automatically removed from ChannelGroup,
// so there is no need to do "channels.remove(ctx.channel());"
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, String s) throws Exception { // (4)
Channel incoming = ctx.channel();
for (Channel channel : channels) {
if (channel != incoming){
channel.writeAndFlush("[" + incoming.remoteAddress() + "]" + s + "\n");
} else {
channel.writeAndFlush("[you]" + s + "\n");
}
}
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception { // (5)
Channel incoming = ctx.channel();
System.out.println("SimpleChatClient:"+incoming.remoteAddress()+"在线");
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception { // (6)
Channel incoming = ctx.channel();
System.out.println("SimpleChatClient:"+incoming.remoteAddress()+"掉线");
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { // (7)
Channel incoming = ctx.channel();
System.out.println("SimpleChatClient:"+incoming.remoteAddress()+"异常");
// 当出现异常就关闭连接
cause.printStackTrace();
ctx.close();
}
}
服务端初始化类
public class SimpleChatServerInitializer extends
ChannelInitializer {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast("framer", new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));
pipeline.addLast("decoder", new StringDecoder());
pipeline.addLast("encoder", new StringEncoder());
pipeline.addLast("handler", new SimpleChatServerHandler());
System.out.println("SimpleChatClient:"+ch.remoteAddress() +"连接上");
}
}
服务端
public class SimpleChatServer {
private int port;
public SimpleChatServer(int port) {
this.port = port;
}
public void run() throws Exception {
EventLoopGroup bossGroup = new NioEventLoopGroup(); // (1)
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap(); // (2)
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class) // (3)
.childHandler(new SimpleChatServerInitializer()) //(4)
.option(ChannelOption.SO_BACKLOG, 128) // (5)
.childOption(ChannelOption.SO_KEEPALIVE, true); // (6)
System.out.println("SimpleChatServer 启动了");
// 绑定端口，开始接收进来的连接
ChannelFuture f = b.bind(port).sync(); // (7)
// 等待服务器 socket 关闭 。
// 在这个例子中，这不会发生，但你可以优雅地关闭你的服务器。
f.channel().closeFuture().sync();
} finally {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
System.out.println("SimpleChatServer 关闭了");
}
}
public static void main(String[] args) throws Exception {
int port;
if (args.length > 0) {
port = Integer.parseInt(args[0]);
} else {
port = 8080;
}
new SimpleChatServer(port).run();
}
}
启动项目，启动一个服务端，三个客户端
服务端
客户端
客户端1发送消息，其他连接到服务器的客户端会收到客户端1的消息，并且显示客户端1的地址和端口，发送方不会显示。
参考
Netty 实现聊天功能