前言介绍：
本案例主要介绍如何使用Netty开发websocket。
环境需求：
1、jdk1.7
2、Eclipse
3、Netty5.0
4、支持websocket的浏览器[火狐]
工程截图：
代码部分：
服务端：
Global.java
package com.itstack.netty.common;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.util.concurrent.GlobalEventExecutor;
public class Global {
public static ChannelGroup group = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
}
ChildChannelHandler.java
package com.itstack.netty.websocket;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.stream.ChunkedWriteHandler;
public class ChildChannelHandler extends ChannelInitializer<SocketChannel>{
@Override
protected void initChannel(SocketChannel e) throws Exception {
e.pipeline().addLast("http-codec",new HttpServerCodec());
e.pipeline().addLast("aggregator",new HttpObjectAggregator(65536));
e.pipeline().addLast("http-chunked",new ChunkedWriteHandler());
e.pipeline().addLast("handler",new MyWebSocketServerHandler());
}
}
MyWebSocketServerHandler.java
package com.itstack.netty.websocket;
import java.util.Date;
import java.util.logging.Level;
import java.util.logging.Logger;
import com.itstack.netty.common.Global;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.DefaultFullHttpRequest;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.handler.codec.http.websocketx.CloseWebSocketFrame;
import io.netty.handler.codec.http.websocketx.PingWebSocketFrame;
import io.netty.handler.codec.http.websocketx.PongWebSocketFrame;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketServerHandshaker;
import io.netty.handler.codec.http.websocketx.WebSocketServerHandshakerFactory;
import io.netty.util.CharsetUtil;
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 channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}
private void handlerWebSocketFrame(ChannelHandlerContext ctx,
WebSocketFrame frame) {
// 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);
if (logger.isLoggable(Level.FINE)) {
logger
.fine(String.format("%s received %s", ctx.channel(),
request));
}
TextWebSocketFrame tws = new TextWebSocketFrame(new Date().toString()
+ ctx.channel().id() + "：" + 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) {
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:7397/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) {
// 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) {
return false;
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
cause.printStackTrace();
ctx.close();
}
}
NettyServer.java
package com.itstack.netty.websocket;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
public class NettyServer {
public static void main(String[] args) {
new NettyServer().run();
}
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(7397).sync().channel();
ch.closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
}finally{
bossGroup.shutdownGracefully();
workGroup.shutdownGracefully();
}
}
}
客户端：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
</head>
</head>
<script type="text/javascript">
var socket;
if(!window.WebSocket){
window.WebSocket = window.MozWebSocket;
}
if(window.WebSocket){
socket = new WebSocket("ws://localhost:7397/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！");
}
}
</script>
<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>
</html>
测试运行：
1、启动NettyServer
2、启动支持websocket的浏览器，打开index.html【开启2个以上】
3、服务端输出结果：
服务端开启等待客户端连接 ... ...
客户端与服务端连接开启
客户端与服务端连接开启
客户端与服务端连接关闭
客户端与服务端连接开启
服务端收到：Netty The Sinper
服务端收到：Netty The Sinper
服务端收到：www.itstack.org
服务端收到：www.itstack.org
服务端收到：您好，您也在学习Netty吗？
服务端收到：是的！一起学习吧！
服务端收到：嗯，到群里来吧5360392
服务端收到：好的，么么大
4、客户端输出截图：
源码下载：
