使用websocket的作用，使前后端保持长连接通信，可互相发送消息。运行通过的代码如下：
一、后端：
1、引进jar包：
<properties>
<io.netty.netty-all.version>4.0.53.Final</io.netty.netty-all.version>
</properties>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>${io.netty.netty-all.version}</version>
</dependency>
2、新建类：
A、global类：
public class Global {
/**在Netty中提供了ChannelGroup接口，该接口继承Set接口，因此可以通过ChannelGroup可管理服务器端所有的连接的Channel，然后对所有的连接Channel广播消息。*/
public static ChannelGroup group = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
}
B、ChildChannelHandler配置类：
public class ChildChannelHandler extends ChannelInitializer<SocketChannel>{
@Override
protected void initChannel(SocketChannel e) throws Exception {
/**http解码,上述代码表示将请求和应答的消息编码或者解码为HTTP消息；*/
e.pipeline().addLast("http-codec",new HttpServerCodec());
/**上述代码表示将HTTP消息的多个部分组合成一条完整的HTTP消息；*/
e.pipeline().addLast("aggregator",new HttpObjectAggregator(65536));
/**上述代码表示向客户端发送HTML5文件，主要用于支持浏览器和服务端进行websocket通信；*/
e.pipeline().addLast("http-chunked",new ChunkedWriteHandler());
/**MyWebSocketServerHandler 自己定义的类，用以处理传过来的数据*/
e.pipeline().addLast("handler",new MyWebSocketServerHandler());
}
}
C、WebSocketServer 启动类：
public class WebSocketServer {
public void run(){
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workGroup);
b.channel(NioServerSocketChannel.class);
b.childHandler(new ChildChannelHandler());
System.out.println("服务端开启等待客户端连接 ... ...");
Channel ch = b.bind(8056).sync().channel();
ch.closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
}finally{
bossGroup.shutdownGracefully();
workGroup.shutdownGracefully();
}
}
}
D、具体业务逻辑类MyWebSocketServerHandler ：
public class MyWebSocketServerHandler extends SimpleChannelInboundHandler<Object>{
private static final Logger logger = Logger
.getLogger(WebSocketServerHandshaker.class.getName());
private WebSocketServerHandshaker handshaker;
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
// 添加
Global.group.add(ctx.channel());
System.out.println("客户端与服务端连接开启");
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
// 移除
Global.group.remove(ctx.channel());
System.out.println("客户端与服务端连接关闭");
}
/*@Override
protected void messageReceived(ChannelHandlerContext ctx, Object msg)
throws Exception {
if (msg instanceof FullHttpRequest) {
handleHttpRequest(ctx, ((FullHttpRequest) msg));
} else if (msg instanceof WebSocketFrame) {
handlerWebSocketFrame(ctx, (WebSocketFrame) msg);
}
}*/
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
// TODO Auto-generated method stub
if (msg instanceof FullHttpRequest) {
System.out.println("进程：1");
handleHttpRequest(ctx, ((FullHttpRequest) msg));
} else if (msg instanceof WebSocketFrame) {
System.out.println("进程：2");
handlerWebSocketFrame(ctx, (WebSocketFrame) msg);
}
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}
private void handlerWebSocketFrame(ChannelHandlerContext ctx,
WebSocketFrame frame) {
System.out.println("进程：3");
// 判断是否关闭链路的指令
if (frame instanceof CloseWebSocketFrame) {
handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame
.retain());
}
// 判断是否ping消息
if (frame instanceof PingWebSocketFrame) {
ctx.channel().write(
new PongWebSocketFrame(frame.content().retain()));
return;
}
// 本例程仅支持文本消息，不支持二进制消息
if (!(frame instanceof TextWebSocketFrame)) {
System.out.println("本例程仅支持文本消息，不支持二进制消息");
throw new UnsupportedOperationException(String.format(
"%s frame types not supported", frame.getClass().getName()));
}
// 返回应答消息
String request = ((TextWebSocketFrame) frame).text();
System.out.println("服务端收到：" + request);
TextWebSocketFrame tws = new TextWebSocketFrame(new Date().toString()
+ "：" + request);
// 群发
Global.group.writeAndFlush(tws);
// 返回【谁发的发给谁】
// ctx.channel().writeAndFlush(tws);
}
private void handleHttpRequest(ChannelHandlerContext ctx,
FullHttpRequest req) {
System.out.println("进程：4");
if (!req.getDecoderResult().isSuccess()
|| (!"websocket".equals(req.headers().get("Upgrade")))) {
sendHttpResponse(ctx, req, new DefaultFullHttpResponse(
HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST));
return;
}
WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(
"ws://localhost:8056/websocket", null, false);
handshaker = wsFactory.newHandshaker(req);
if (handshaker == null) {
WebSocketServerHandshakerFactory
.sendUnsupportedWebSocketVersionResponse(ctx.channel());
} else {
handshaker.handshake(ctx.channel(), req);
}
}
private static void sendHttpResponse(ChannelHandlerContext ctx,
FullHttpRequest req, DefaultFullHttpResponse res) {
System.out.println("进程：5");
// 返回应答给客户端
if (res.getStatus().code() != 200) {
ByteBuf buf = Unpooled.copiedBuffer(res.getStatus().toString(),
CharsetUtil.UTF_8);
res.content().writeBytes(buf);
buf.release();
}
// 如果是非Keep-Alive，关闭连接
ChannelFuture f = ctx.channel().writeAndFlush(res);
if (!isKeepAlive(req) || res.getStatus().code() != 200) {
f.addListener(ChannelFutureListener.CLOSE);
}
}
private static boolean isKeepAlive(FullHttpRequest req) {
System.out.println("进程：8");
return false;
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
cause.printStackTrace();
System.out.println("进程：7");
ctx.close();
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
// TODO Auto-generated method stub
System.out.println("进程：6");
}
}
E、启动接口websocket：
new WebSocketServer().run();
二、前端：
1.html 文件：
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8">
<title>websocket</title>
<meta name="renderer" content="webkit">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="format-detection" content="telephone=no">
<link rel="stylesheet" href="ag/css/layui.css" media="all"/>
<link rel="stylesheet" href="ag/css/bootstrap.min.css" media="all">
</head>
<body>
<form onSubmit="return false;">
<input type = "text" name="message" value="Netty The Sinper"/>
<br/><br/>
<input type="button" value="发送 WebSocket 请求消息" onClick="send(this.form.message.value)"/>
<hr color="blue"/>
<h3>服务端返回的应答消息</h3>
<textarea id="responseText" style="width: 1024px;height: 300px;"></textarea>
</form>
</body>
<script type="text/javascript" src="ag/js/jquery.min.js"></script>
<script type="text/javascript" src="ag/js/bootstrap.min.js"></script>
<script type="text/javascript" src="ag/js/layui.js"></script>
<script type="text/javascript" src="ag/js/websocket.js"></script>
</html>
2、js文件：
var socket;
if(!window.WebSocket){
window.WebSocket = window.MozWebSocket;
}
if(window.WebSocket){
socket = new WebSocket("ws://localhost:8056/websocket");
socket.onmessage = function(event){
var ta = document.getElementById('responseText');
ta.value += event.data+"\r\n";
};
socket.onopen = function(event){
var ta = document.getElementById('responseText');
ta.value = "打开WebSoket 服务正常，浏览器支持WebSoket!"+"\r\n";
};
socket.onclose = function(event){
var ta = document.getElementById('responseText');
ta.value = "";
ta.value = "WebSocket 关闭"+"\r\n";
};
}else{
alert("您的浏览器不支持WebSocket协议！");
}
function send(message){
if(!window.WebSocket){return;}
if(socket.readyState == WebSocket.OPEN){
socket.send(message);
}else{
alert("WebSocket 连接没有建立成功！");
}
}