之前做过一个IM的项目，里面涉及了基本的聊天功能，所以注意这系列的文章不是练习，不含基础和逐步学习的部分，直接开始实战和思想引导，基础部分需要额外的去补充，我有精力的话可以后续出一系列的文章。
为什么第一篇是聊天室，聊天室是最容易实现的部分。也是IM结构最简单的一部分，其次作单聊和群聊，业务逻辑层层递增，彻底的拿下聊天室的代码，进阶单聊和群聊就很简单了，后续我还会推出直播间的实现。
如果单纯想实现聊天室很简单，但是我尽量会把流程都走全，为了方便理解。
主要由两个功能类实现：初始化类+响应处理类
0. 准备工作
添加pom.xml
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.2.Final</version>
</dependency>
1. 辅助接口实现
辅助接口让服务架构更加清晰，这里有两个接口，一个用来处理Http请求，一个处理Webocket请求。
MyHttpService.java
/**
* 处理 http请求
*/
public interface MyHttpService {
void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest request);
}
MyWebSocketService.java
/**
* 处理 WebSocket 请求中的frame
*/
public interface MyWebSocketService {
void handleFrame(ChannelHandlerContext ctx, WebSocketFrame frame);
}
那么问题来了，谁来实现这两个类呢，谁来处理这两种请求的分发呢。
下面来看服务响应处理类：WebSocketServerHandler.java
2. 请求处理类
继承SimpleChannelInboundHandler类，实现
channelRead0()handlerAdded()handlerRemoved()exceptionCaught()等方法，第一个是必选方法，其他方法供我们做一些标记和后续处理。
WebSocketServerHandler.java
@Slf4j
public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object> {
private MyHttpService httpService;
private MyWebSocketService webSocketService;
public static ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
public WebSocketServerHandler(MyHttpService httpService, MyWebSocketService webSocketService) {
super();
this.httpService = httpService;
this.webSocketService = webSocketService;
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
if (msg instanceof FullHttpRequest) {
httpService.handleHttpRequest(ctx, (FullHttpRequest) msg);
} else if (msg instanceof WebSocketFrame) {
webSocketService.handleFrame(ctx, (WebSocketFrame) msg);
}
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
channels.add(ctx.channel());
channels.writeAndFlush(new TextWebSocketFrame(ctx.channel() +"上线了"));
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
channels.remove(ctx.channel());
channels.writeAndFlush(new TextWebSocketFrame(ctx.channel() +"下线了"));
}
/**
* 发生异常时处理
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
channels.remove(ctx.channel());
ctx.close();
log.info("异常信息：{}",cause.getMessage());
}
}
- 创建ChannelGroup,来保存每个已经建立连接的channel，在
handlerAdded()方法中channels.add(ctx.channel());,相应的在handlerRemoved方法中remove。 - 在
channelRead0()方法中，实现了对请求的识别和分别处理。 exceptionCaught()方法为发生异常时处理。
3. 初始化类实现
@Slf4j
public class WebSocketServer implements MyHttpService, MyWebSocketService {
/**
* 握手用的 变量
*/
private static final AttributeKey<WebSocketServerHandshaker> ATTR_HAND_SHAKER = AttributeKey.newInstance("ATTR_KEY_CHANNEL_ID");
private static final int MAX_CONTENT_LENGTH = 65536;
/**
* 请求类型常量
*/
private static final String WEBSOCKET_UPGRADE = "websocket";
private static final String WEBSOCKET_CONNECTION = "Upgrade";
private static final String WEBSOCKET_URI_ROOT_PATTERN = "ws://%s:%d";
/**
* 用户字段
*/
private String host;
private int port;
/**
* 保存 所有的连接
*/
private Map<ChannelId, Channel> channelMap = new HashMap<>();
private final String WEBSOCKET_URI_ROOT;
public WebSocketServer(String host, int port) {
this.host = host;
this.port = port;
// 将 ip 和端口 按照格式 赋值给 uri
WEBSOCKET_URI_ROOT = String.format(WEBSOCKET_URI_ROOT_PATTERN, host, port);
}
public void start(){
// 实例化 nio监听事件池
EventLoopGroup bossGroup = new NioEventLoopGroup();
// 实例化 nio工作线程池
EventLoopGroup workerGroup = new NioEventLoopGroup();
// 启动器
ServerBootstrap bootstrap = new ServerBootstrap();
bootstrap.group(bossGroup,workerGroup);
bootstrap.channel(NioServerSocketChannel.class);
bootstrap.childHandler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel channel) throws Exception {
ChannelPipeline pl = channel.pipeline();
// 保存 该channel 到map中
channelMap.put(channel.id(),channel);
log.info("new channel {}",channel);
channel.closeFuture().addListener((ChannelFutureListener) channelFuture -> {
log.info("channel close future {}",channelFuture);
//关闭后 从map中移除
channelMap.remove(channelFuture.channel().id());
});
//添加 http 编解码
pl.addLast(new HttpServerCodec());
// 聚合器
pl.addLast(new HttpObjectAggregator(MAX_CONTENT_LENGTH));
// 支持大数据流
pl.addLast(new ChunkedWriteHandler());
// 设置 websocket 服务处理方式
pl.addLast(new WebSocketServerHandler(WebSocketServer.this, WebSocketServer.this));
}
});
/**
* 实例化完毕后，需要完成端口绑定
*/
try {
ChannelFuture channelFuture = bootstrap.bind(host,port).addListener((ChannelFutureListener) channelFuture1 -> {
if (channelFuture1.isSuccess()){
log.info("webSocket started");
}
}).sync();
channelFuture.channel().closeFuture().addListener((ChannelFutureListener) channelFuture12 ->
log.info("server channel {} closed.", channelFuture12.channel())).sync();
} catch (InterruptedException e) {
e.printStackTrace();
System.out.println("绑定端口失败");
}finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
log.info("webSocket shutdown");
}
@Override
public void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest request) {
//判断是不是 socket 请求
if (isWebSocketUpgrade(request)){
//如果是webSocket请求
log.info("请求是webSocket协议");
// 获取子协议
String subProtocols = request.headers().get(HttpHeaderNames.SEC_WEBSOCKET_PROTOCOL);
//握手工厂 设置 uri+协议+不允许扩展
WebSocketServerHandshakerFactory handshakerFactory = new WebSocketServerHandshakerFactory(WEBSOCKET_URI_ROOT,subProtocols,false);
// 从工厂中实例化一个 握手请求
WebSocketServerHandshaker handshaker = handshakerFactory.newHandshaker(request);
if (handshaker == null){
//握手失败：不支持的协议
WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());
}else {
//响应请求:将 握手转交给 channel处理
handshaker.handshake(ctx.channel(),request);
//将 channel 与 handshaker 绑定
ctx.channel().attr(ATTR_HAND_SHAKER).set(handshaker);
}
return;
}else {
// 不处理 HTTP 请求
log.info("不处理 HTTP 请求");
}
}
@Override
public void handleFrame(ChannelHandlerContext ctx, WebSocketFrame frame) {
/**
* text frame handler
*/
if (frame instanceof TextWebSocketFrame){
String text = ((TextWebSocketFrame) frame).text();
TextWebSocketFrame textWebSocketFrame = new TextWebSocketFrame(text);
log.info("receive textWebSocketFrame from channel: {} , 目前一共有{}个在线",ctx.channel(),channelMap.size());
//发给其它的 channel (群聊功能)
for (Channel ch: channelMap.values()){
if (ch.equals(ctx.channel())){
continue;
}
//将 text frame 写出
ch.writeAndFlush(textWebSocketFrame);
log.info("消息已发送给{}",ch);
log.info("write text: {} to channel: {}",textWebSocketFrame,ctx.channel());
}
return;
}
/**
* ping frame , 回复 pong frame
*/
if (frame instanceof PingWebSocketFrame){
log.info("receive pingWebSocket from channel: {}",ctx.channel());
ctx.channel().writeAndFlush(new PongWebSocketFrame(frame.content().retain()));
return;
}
/**
* pong frame, do nothing
*/
if (frame instanceof PongWebSocketFrame){
log.info("receive pongWebSocket from channel: {}",ctx.channel());
return;
}
/**
* close frame, close
*/
if (frame instanceof CloseWebSocketFrame){
log.info("receive closeWebSocketFrame from channel: {}", ctx.channel());
//获取到握手信息
WebSocketServerHandshaker handshaker = ctx.channel().attr(ATTR_HAND_SHAKER).get();
if (handshaker == null){
log.error("channel: {} has no handShaker", ctx.channel());
return;
}
handshaker.close(ctx.channel(),((CloseWebSocketFrame) frame).retain());
return;
}
/**
* 剩下的都是 二进制 frame ，忽略
*/
log.warn("receive binary frame , ignore to handle");
}
/**
* 判断是否是 webSocket 请求
*/
private boolean isWebSocketUpgrade(FullHttpRequest req) {
HttpHeaders headers = req.headers();
return req.method().equals(HttpMethod.GET)
&& headers.get(HttpHeaderNames.UPGRADE).contains(WEBSOCKET_UPGRADE)
&& headers.get(HttpHeaderNames.CONNECTION).contains(WEBSOCKET_CONNECTION);
}
}
l.addLast(new WebSocketServerHandler(WebSocketServer.this, WebSocketServer.this));添加自己的响应处理。WebSocketServerHandler是第二点实现的请求处理类.private Map<ChannelId, Channel> channelMap = new HashMap<>();来将ChannelId和CHannel对应保存。方便后来对应获取。bootstrap.bind(host,port)也可以替换成仅bind端口。
public ChannelFuture bind(String inetHost, int inetPort) {
return bind(new InetSocketAddress(inetHost, inetPort));
}
public synchronized InetAddress anyLocalAddress() {
if (anyLocalAddress == null) {
anyLocalAddress = new Inet4Address(); // {0x00,0x00,0x00,0x00}
anyLocalAddress.holder().hostName = "0.0.0.0";
}
return anyLocalAddress;
}
它默认会给0.0.0.0端口开放服务。
4. handleHttpRequest和handleFrame是MyWebSocketService类的一个实现。
5. 各个细节都有注释，仔细看注释。
4. 启动服务
public class Main {
public static void main(String[] args) {
new WebSocketServer("192.168.1.33",9999).start();
}
}
局域网内如何测试?
我用的是npm 的一个serve 服务来搞局域网。 官网介绍：www.npmjs.com/package/ser… 我的文章：React打包注意事项及静态文件服务搭建
这下保证你的手机和电脑都在局域网内，就可以访问你自己的群聊了。
5. 前端页面
要送就送一套。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style type="text/css">
.talk_con{
width:600px;
height:500px;
border:1px solid #666;
margin:50px auto 0;
background:#f9f9f9;
}
.talk_show{
width:580px;
height:420px;
border:1px solid #666;
background:#fff;
margin:10px auto 0;
overflow:auto;
}
.talk_input{
width:580px;
margin:10px auto 0;
}
.whotalk{
width:80px;
height:30px;
float:left;
outline:none;
}
.talk_word{
width:420px;
height:26px;
padding:0px;
float:left;
margin-left:10px;
outline:none;
text-indent:10px;
}
.talk_sub{
width:56px;
height:30px;
float:left;
margin-left:10px;
}
.atalk{
margin:10px;
}
.atalk span{
display:inline-block;
background:#0181cc;
border-radius:10px;
color:#fff;
padding:5px 10px;
}
.btalk{
margin:10px;
text-align:right;
}
.btalk span{
display:inline-block;
background:#ef8201;
border-radius:10px;
color:#fff;
padding:5px 10px;
}
</style>
<script type="text/javascript">
//
document.onkeydown = function (ev) {
if (ev && ev.keyCode == 13){
send();
clear();
}
}
var socket;
if (window.WebSocket) {
socket = new WebSocket("ws://192.168.1.33:9999");
// socket = new WebSocket("ws://127.0.0.1:9999");
// socket = new WebSocket("ws://192.168.43.186:9999");
socket.onmessage = function (ev) {
atalkAppendIn("接收:"+socket.channel + ":" + ev.data)
};
socket.onopen = function () {
btalkAppendIn("连接已建立");
}
socket.onclose = function () {
btalkAppendIn("连接关闭");
};
}else {
alert("浏览器不支持");
}
function send(){
var message = document.getElementById("talkwords");
if (!window.WebSocket){
return
}
if (socket.readyState === WebSocket.OPEN){
socket.send(message.value);
btalkAppendIn("发送:"+ message.value);
clear();
} else {
alert("WebSocket 建立失败");
}
}
function atalkAppendIn(text) {
var append = document.getElementById("words");
append.innerHTML+= '<div class="atalk"><span>'+ text +'</span></div>';
}
function btalkAppendIn(text) {
var append = document.getElementById("words");
append.innerHTML+= '<div class="btalk"><span>'+ text +'</span></div>';
}
function clear () {
var elementById = document.getElementById("talkwords");
elementById.value = "";
}
</script>
</head>
<body>
<div class="talk_con">
<div class="talk_show" id="words">
</div>
<div class="talk_input">
<!--<select class="whotalk" id="who">-->
<!--<option value="0">A说：</option>-->
<!--<option value="1">B说：</option>-->
<!--</select>-->
<input type="text" class="talk_word" id="talkwords">
<input type="button" onclick="send()" value="发送" class="talk_sub" id="talksub">
</div>
</div>
</body>
</html>
socket = new WebSocket("ws://192.168.1.33:9999");注意这里ip和port与服务一一对应。socket.onmessage()是获取socket信息。socket.onopen是创建连接。socket.onclose是关闭连接。socket.send(message.value);是发送socket信息。
控制台输出：
15:12:42.443 [nioEventLoopGroup-3-6] INFO com.fantj.springbootjpa.netty.WebSocketServer - receive textWebSocketFrame from channel: [id: 0x0d08c657, L:/192.168.1.33:9999 - R:/192.168.1.33:50440] , 目前一共有2个在线
15:12:42.443 [nioEventLoopGroup-3-6] INFO com.fantj.springbootjpa.netty.WebSocketServer - 消息已发送给[id: 0xacd5c1ad, L:/192.168.1.33:9999 - R:/192.168.1.33:50438]
15:12:42.444 [nioEventLoopGroup-3-5] DEBUG io.netty.handler.codec.http.websocketx.WebSocket08FrameEncoder - Encoding WebSocket Frame opCode=1 length=5
15:12:42.443 [nioEventLoopGroup-3-6] INFO com.fantj.springbootjpa.netty.WebSocketServer - write text: TextWebSocketFrame(data: UnpooledUnsafeHeapByteBuf(ridx: 0, widx: 5, cap: 15)) to channel: [id: 0x0d08c657, L:/192.168.1.33:9999 - R:/192.168.1.33:50440]
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java架构获取架构视频资源(后期还会分享不同的优质资源噢)。
