1、编写服务端
public class MyServer {
public static void main(String[] args) {
EventLoopGroup boss = new NioEventLoopGroup();
EventLoopGroup worker = new NioEventLoopGroup();
try {
ServerBootstrap bootstrap = new ServerBootstrap();
bootstrap.group(boss, worker)
.channel(NioServerSocketChannel.class)
.handler(new LoggingHandler(LogLevel.INFO))
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
//基于http协议，使用http的编码和解码器
pipeline.addLast(new HttpServerCodec());
//以块方式写，添加ChunkedWriteHandler处理器
pipeline.addLast(new ChunkedWriteHandler());
/*
1. http数据在传输过程中是分段, HttpObjectAggregator ，就是可以将多个段聚合
2. 这就是为什么，当浏览器发送大量数据时，就会发出多次http请求
*/
pipeline.addLast(new HttpObjectAggregator(8192));
/*
* ws://localhost:8888/hello 表示请求的uri
* WebSocketServerProtocolHandler 核心功能是将http协议升级为ws协议，保持长连接
*/
pipeline.addLast(new WebSocketServerProtocolHandler("/hello"));
//业务处理的handler
pipeline.addLast(new MyTextWebSocketFrameHandler());
}
});
ChannelFuture channelFuture = bootstrap.bind(8888).sync();
channelFuture.channel().closeFuture().sync();
}catch (Exception e) {
}finally {
boss.shutdownGracefully();
worker.shutdownGracefully();
}
}
}
2、编写业务处理handler
public class MyTextWebSocketFrameHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception {
System.out.println("服务器端收到消息 " + msg.text());
//发送到web客户端
ctx.channel().writeAndFlush(new TextWebSocketFrame("服务器时间" + LocalDateTime.now() + ", " + msg.text() + "\n"));
}
/**
* @Description web客户端连接后调用
**/
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
System.out.println("服务器 handlerAdded 被调用 " + ctx.channel().id().asLongText());
System.out.println("服务器 handlerAdded 被调用 " + ctx.channel().id().asShortText());
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
System.out.println("服务器 handlerRemoved 被调用 " + ctx.channel().id().asLongText());
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
ctx.close();
}
}
3、编写web客户端
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<script>
var socket;
if (window.WebSocket) {
socket = new WebSocket("ws://localhost:8888/hello");
//接受服务器的信息
socket.onmessage = function (ev) {
var rt = document.getElementById("responseText")
rt.value = rt.value + ev.data;
}
//连接开启
socket.onopen = function (ev) {
var rt = document.getElementById("responseText");
rt.value = "连接开启了...";
}
//连接关闭
socket.onclose = function (ev) {
var rt = document.getElementById("responseText");
rt.value = rt.value + "\n" + "连接关闭了...";
}
}else {
alert("当前浏览器不支持websocket")
}
function send(message) {
if (!window.socket) {
return;
}
if (socket.readyState == WebSocket.OPEN) {
socket.send(message);
}else {
alert("连接未开启...")
}
}
</script>
<form action="/hello" method="get" onsubmit="return false">
<textarea name="message" style="height: 300px; width: 300px;"></textarea>
<input type="button" value="发送消息" onclick="send(this.form.message.value)"/>
<textarea id="responseText" style="height: 300px; width: 300px;"></textarea>
<input type="button" value="清空内容" onclick="document.getElementById('responseText').value = ''"/>
</form>
</body>
</html>
4、效果
当服务器关闭后，客户端检测到：
当客户端关闭后，服务端检测到：
