Netty的介绍就不在这里阐述了,前面也写过关于Netty的文章:

Netty(一) springboot整合Netty做心跳检测

Netty(二) springboot 整合netty编写时间服务器

Netty(三) Netty 之传输文件

这里不做过多的介绍,代码里有相应的注释,

首先添加依赖:

<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.21.Final</version>
</dependency>

WebsocketServer

@Component
public class WebsocketServer {

private final static Logger LOGGER = LoggerFactory.getLogger(WebsocketServer.class);
//初始化主线程(boss线程)
NioEventLoopGroup mainGroup = new NioEventLoopGroup();
//初始化从线程池(work线程)
NioEventLoopGroup subGroup = new NioEventLoopGroup();

@PostConstruct
public void start() {
try {
//创建服务启动器
ServerBootstrap serverBootstrap = new ServerBootstrap();
//指定使用主线程和从线程
serverBootstrap.group(mainGroup, subGroup)
//指定使用NIO通道类型
.channel(NioServerSocketChannel.class)
.localAddress(new InetSocketAddress(9001))
//保持长连接
.childOption(ChannelOption.SO_KEEPALIVE, true)
//指定通道初始化器用来加载当Channel收到事件消息后,如何进行业务处理
.childHandler(new WsServerInitializer());
//绑定端口启动服务器,并等待服务启动
ChannelFuture future = serverBootstrap.bind().sync();
if (future.isSuccess()) {
LOGGER.info("启动 Netty 成功");
}
//等待服务器关闭
//future.channel().closeFuture().sync();

future.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}
}

/**
* 销毁
*/
@PreDestroy
public void destroy() {
mainGroup.shutdownGracefully().syncUninterruptibly();
subGroup.shutdownGracefully().syncUninterruptibly();
LOGGER.info("关闭 Netty 成功");
}
}

WsServerInitializer(通道初始化)

/**
* Created by haoxy on 2019/1/4.
* E-mail:hxyHelloWorld@163.com
* github:https://github.com/haoxiaoyong1014
* 通道初始化器
* 用来加载通道处理器
*/
public class WsServerInitializer extends ChannelInitializer<SocketChannel> {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
ChannelPipeline pipeline = socketChannel.pipeline();
//用于支持 http协议
//websocket 基于http协议,需要 http的编码器
pipeline.addLast(new HttpServerCodec())
//对大数据流的支持
.addLast(new ChunkedWriteHandler())
//添加对HTTP请求和响应的聚合器: 只要Netty进行编码都需要使用
//对HttpMessage进行聚合,聚合成FullHttpRequest获取FullHttpResponse
.addLast(new HttpObjectAggregator(1024 * 64))

//-----------支持 webSocket----------
//需要指定接收请求的路由,处理握手动作(close,ping pong),ping+pong=心跳
//必须使用 ws 后缀结尾的 url 才能访问
.addLast(new WebSocketServerProtocolHandler("/ws"))
//添加自定义的 handler
.addLast(new ChatHandler());
}
}

ChatHandler(自定义业务处理类)

/**
* Created by haoxy on 2019/1/4.
* E-mail:hxyHelloWorld@163.com
* github:https://github.com/haoxiaoyong1014
*/
//TextWebSocketFrame 在 netty 中是用于webSocket专门处理文本对象,frame是消息的载体.
public class ChatHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> {


private final static Logger LOGGER = LoggerFactory.getLogger(ChatHandler.class);

//用于记录和管理所有客户端的Channel

private static ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);

private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-mm-dd hh:MM");

//当接收到客户端发过来的消息就会触发此回调
@Override
protected void channelRead0(ChannelHandlerContext channelHandlerContext, TextWebSocketFrame textWebSocketFrame) throws Exception {
String content = textWebSocketFrame.text();
System.out.println("接收到的数据: " + content);
//将消息发给其他客户端排除自己

Channel channel = channelHandlerContext.channel();
for (Channel ch : channels) {
//排除当前通道
if (channel != ch) {
ch.writeAndFlush(new TextWebSocketFrame(sdf.format(new Date()) + ":" + content));
}
}

/*//将接收的消息发送所有的客户端
for (Channel channel : channels) {
channel.writeAndFlush(new TextWebSocketFrame(sdf.format(new Date()) + ":" + content));
}*/
}

//当有新的客户端连接服务器之后,就会自动调用这个方法
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
channels.add(ctx.channel());

}

}

chat.html(前端代码)

 <body>
<input type="text" id="message">
<input type="button" value="发送消息" onclick="sendMsg()">
<br/>
接收到消息:
<p id="server_message" style="background-color: #AAAAAA"></p>

<script>
var websocket = null;
//判断当前浏览器是否支持 webSocket
if (window.WebSocket) {
websocket = new WebSocket("ws://127.0.0.1:9001/ws");
websocket.onopen = function (ev) {
console.log("建立连接");
}
websocket.onclose = function (ev) {
console.log("断开连接");
}
websocket.onmessage = function (ev) {
console.log("接收到服务器的消息" + ev.data);
var server_message = document.getElementById("server_message");
server_message.innerHTML += ev.data + "<br/>";
}
} else {
alert("当前浏览器不支持 webSocket")
}

function sendMsg() {
var message = document.getElementById("message");
websocket.send(message.value)
}
</script>
</body>

案例效果图:

窗口A给窗口B发送消息:

5791552706434_.pic.jpg

窗口B回复窗口A的消息:

5801552706540_.pic.jpg
案例项目地址:

netty-chat

学习资料

线程,BIO,NIO,AIO Netty 手写RPC