Netty5 + WebSocket 练习

1. 了解WebSocket知识
　　略
2. websocket实现系统简单反馈时间

　　WebSocketServerHandler.java

package com.jieli.nettytest.websocketserver;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.stream.ChunkedWriteHandler;

public class WebSocketServer {

public void run(int port){
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
//HttpServerCodec将请求和应答消息编码或解码为HTTP消息
//通常接收到的http是一个片段，如果想要完整接受一次请求所有数据，我们需要绑定HttpObjectAggregator
//然后就可以收到一个FullHttpRequest完整的请求信息了
//ChunkedWriteHandler 向客户端发送HTML5文件，主要用于支持浏览器和服务器进行WebSocket通信
//WebSocketServerHandler自定义Handler
ch.pipeline().addLast("http-codec", new HttpServerCodec())
.addLast("aggregator", new HttpObjectAggregator(65536)) //定义缓冲大小
.addLast("http-chunked", new ChunkedWriteHandler())
.addLast("handler", new WebSocketServerHandler());
}
});

ChannelFuture f = b.bind(port).sync();
System.out.println("start...");
f.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
} finally {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
}
}

public static void main(String[] args) {
new WebSocketServer().run(7777);
}
}

　　WebSocketServerHandler.java

package com.jieli.nettytest.websocketserver;

import java.util.logging.Level;
import java.util.logging.Logger;

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.DefaultFullHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.FullHttpResponse;
import io.netty.handler.codec.http.HttpHeaderUtil;
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 WebSocketServerHandler extends SimpleChannelInboundHandler<Object>{

/**
* 日志
*/
private static final Logger logger =
Logger.getLogger(WebSocketServerHandler.class.getName());
/**
* 全局websocket
*/
private WebSocketServerHandshaker handshaker;

@Override
protected void messageReceived(ChannelHandlerContext ctx, Object msg)
throws Exception {
//普通HTTP接入
if(msg instanceof FullHttpRequest){
handleHttpRequest(ctx, (FullHttpRequest) msg);
}else if(msg instanceof WebSocketFrame){ //websocket帧类型 已连接
//BinaryWebSocketFrame CloseWebSocketFrame ContinuationWebSocketFrame
//PingWebSocketFrame PongWebSocketFrame TextWebScoketFrame
handleWebSocketFrame(ctx, (WebSocketFrame) msg);
}
}

@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
ctx.flush();
}

private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest request){
//如果http解码失败 则返回http异常 并且判断消息头有没有包含Upgrade字段(协议升级)
if(!request.decoderResult().isSuccess()
|| (!"websocket".equals( request.headers().get("Upgrade")))    ){
sendHttpResponse(ctx, request, new DefaultFullHttpResponse(
HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST));
return ;
}
//构造握手响应返回
WebSocketServerHandshakerFactory ws = new WebSocketServerHandshakerFactory("", null, false);
handshaker = ws.newHandshaker(request);
if(handshaker == null){
//版本不支持
WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());
}else{
handshaker.handshake(ctx.channel(), request);
}
}
/**
* websocket帧
* @param ctx
* @param frame
*/
private void handleWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame){
//判断是否关闭链路指令
if(frame instanceof CloseWebSocketFrame){
handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain());
return ;
}
//判断是否Ping消息 -- ping/pong心跳包
if(frame instanceof PingWebSocketFrame){
ctx.channel().write(new PongWebSocketFrame(frame.content().retain()));
return ;
}
//本程序仅支持文本消息， 不支持二进制消息
if(!(frame instanceof TextWebSocketFrame)){
throw new UnsupportedOperationException(
String.format("%s frame types not supported", frame.getClass().getName()));
}

//返回应答消息 text文本帧
String request = ((TextWebSocketFrame) frame).text();
//打印日志
if(logger.isLoggable(Level.FINE)){
logger.fine(String.format("%s received %s", ctx.channel(), request));
}
//发送到客户端websocket
ctx.channel().write(new TextWebSocketFrame(request
+ ", 欢迎使用Netty WebSocket服务， 现在时刻:"
+ new java.util.Date().toString()));
}

/**
* response
* @param ctx
* @param request
* @param response
*/
private static void sendHttpResponse(ChannelHandlerContext ctx,
FullHttpRequest request, FullHttpResponse response){
//返回给客户端
if(response.status().code() != HttpResponseStatus.OK.code()){
ByteBuf buf = Unpooled.copiedBuffer(response.status().toString(), CharsetUtil.UTF_8);
response.content().writeBytes(buf);
buf.release();
HttpHeaderUtil.setContentLength(response, response.content().readableBytes());
}
//如果不是keepalive那么就关闭连接
ChannelFuture f = ctx.channel().writeAndFlush(response);
if(!HttpHeaderUtil.isKeepAlive(response)
|| response.status().code() != HttpResponseStatus.OK.code()){
f.addListener(ChannelFutureListener.CLOSE);
}
}

/**
* 异常 出错
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
cause.printStackTrace();
ctx.close();
}
}

　　WebSocketServer.html (这个随便放都可以，到时候双击打开这个即可，不由服务器提供)

<html>
<head>
<meta charset="utf-8">
<title>Netty websocket 时间服务器</title>
</head>
<body>
<form action="" onsubmit="return false;">
<input type="text" name="message" value="..."/>
<br>
<input type="button" value="send" value="发送websocket请求消息" onclick="send(this.form.message.value);" />
<hr color="blue">
<h3>服务器返回信息</h3>
<textarea id="responseText" rows="10" cols=""></textarea>
</form>
</body>

<script type="text/javascript">
var socket;
if(!window.WebSocket){
window.WebSocket = window.MozWebSocket;
}
if(window.WebSocket){
socket = new WebSocket("ws://localhost:7777/websocket");
socket.onmessage = function(event){
var ta = document.getElementById('responseText');
ta.value="";
ta.value=event.data;
};
socket.onopen = function(event){
var ta = document.getElementById('responseText');
ta.value = "打开websocket服务正常";
}
socket.onclose = function(event){
var ta = document.getElementById('responseText');
ta.value="";
ta.value="websocket关闭";
}
}else{
alert("对不起，您的浏览器不支持WebSocket.");
}

function send(message){
if(!window.WebSocket){
return ;
}
if(socket.readyState == WebSocket.OPEN){
socket.send(message);
}else{
alert("WebSocket 连接创建失败.");
}
}
</script>
</html>

　　运行结果

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>WebSocket Chat</title>
</head>
<body>
<script type="text/javascript">
var socket;
if (!window.WebSocket) {
window.WebSocket = window.MozWebSocket;
}
if (window.WebSocket) {
socket = new WebSocket("ws://localhost:8080/ws");
socket.onmessage = function(event) {
var ta = document.getElementById('responseText');
ta.value = ta.value + '\n' + event.data
};
socket.onopen = function(event) {
var ta = document.getElementById('responseText');
ta.value = "连接开启!";
};
socket.onclose = function(event) {
var ta = document.getElementById('responseText');
ta.value = ta.value + "连接被关闭";
};
} else {
alert("你的浏览器不支持 WebSocket！");
}

function send(message) {
if (!window.WebSocket) {
return;
}
if (socket.readyState == WebSocket.OPEN) {
socket.send(message);
} else {
alert("连接没有开启.");
}
}
</script>
<form onsubmit="return false;">
<h3>WebSocket 聊天室：</h3>
<textarea id="responseText" style="width: 500px; height: 300px;"></textarea>
<br>
<input type="text" name="message"  style="width: 300px" value="Welcome to localhost">
<input type="button" value="发送消息" onclick="send(this.form.message.value)">
<input type="button" onclick="javascript:document.getElementById('responseText').value=''" value="清空聊天记录">
</form>
<br>
Netty SEO 优化
Netty 是什么
Netty 怎么样
Netty4 Netty5 区别
Netty 效率
Netty 版本区别
Netty 和 Mina
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NIO 编程
Netty NIO 开发
Netty3 Netty4 Netty5
Netty 好处
Netty 一般注意什么
Netty 例子程序
Netty Hello World
Netty 聊天程序
Netty Web HTML HTTP FTP SSL
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Netty 连接数
Netty 源码
<br>
</body>
</html>

View Code
　　运行结果，依次运行1，2，3



　　服务器打印结果



参考资料:
　　《Netty 权威指南》
　　https://zh.wikipedia.org/wiki/WebSocket
　　https://www.zhihu.com/question/20215561
　　http://waylau.com/netty-websocket-chat/

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