websocket实现客户端跟服务端的双向传输，解决客户端向服务端轮训请求。应用到推送GPS位置信息，弹幕，聊天信息等场景。
一、Java服务端实现
maven依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>核心服务代码
@Configuration
public class WebSocketConfig {
@Bean
public ServerEndpointExporter serverEndpointExporter() {
return new ServerEndpointExporter();
}
}主要是OnOpen OnClose OnMessage OnError方法，里面再买上业务处理；
@Slf4j
@ServerEndpoint(value = "/websocket/user/{accessToken}")
@Component
@EnableScheduling
public class WebSocketUserServer {
//静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。
private static AtomicInteger onlineCount = new AtomicInteger(0);
//concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。
private static CopyOnWriteArrayList<UserSocket> userSockets = new CopyOnWriteArrayList<>();
//与某个客户端的连接会话，需要通过它来给客户端发送数据
private Session session;
/*
连接打开时执行
*/
@OnOpen
public void onOpen(@PathParam("accessToken") String accessToken , Session session) {
open:{
addOnlineCount(); //在线数加1
this.session = session;
log.info("WebSocketUserServer 有新连接加入！当前在线人数为" + getOnlineCount());
if(accessToken ==null || "".equals(accessToken)){
log.info("WebSocketUserServer onOpen accessToken is null");
closeSession(session);
break open;
}
//校验accessToken,获取user信息
//获取service方法
UcTokenFeign ucTokenFeign = SpringUtil.getBean(UcTokenFeign.class) ;
ObjectRestResponse<UcTokenWebsocketVo> userResult = ucTokenFeign.getUserInfo(accessToken) ;
if(userResult.getStatus() != CodeStatus.CODE_SUCCESS.getValue()
||userResult.getData() == null){
log.info("WebSocketUserServer onOpen token feign not success:"+userResult.getMsg());
closeSession(session);
break open;
}
//添加到用户Session对应关系中
UserSocket userSocket = new UserSocket();
userSocket.setUserId(userResult.getData().getUserId())
userSocket.setWebSocketUserServer(this);
userSockets.add(userSocket) ;
// try {
// sendMessage("server连接成功");
// } catch (IOException e) {
// log.error("websocket IO异常");
// }
log.info("WebSocketUserServer Connected ... " + session.getId());
}
}
/*
服务端不接收非合规的client，进行关闭操作
*/
private void closeSession(Session session){
try {
session.close();
} catch (IOException e) {
log.error("WebSocketUserServer close error:"+e);
e.printStackTrace();
}
}
/**
* 连接关闭调用的方法
*/
@OnClose
public void onClose() {
subOnlineCount(); //在线数减1
log.info("WebSocketUserServer 有一连接关闭！当前在线人数为" + getOnlineCount());
userSockets.stream()
.forEach(u ->{
if(u.getWebSocketUserServer() == this){
userSockets.remove(u) ;
log.info("WebSocketUserServer userSockets remove user socket,user:"+u.getUserId());
}
} );
log.info("WebSocketUserServer 删除关闭连接的对应关系");
}
/**
* 收到客户端消息后调用的方法
*
* @param message 客户端发送过来的消息*/
@OnMessage
public void onMessage(String message, Session session) {
log.info("WebSocketUserServer 来自客户端的消息:" + message);
// //群发消息
// for (WebSocketUserServer item : webSocketSet) {
// try {
// item.sendMessage(message);
// } catch (IOException e) {
// e.printStackTrace();
// }
// }
}
/**
*
* @param session
* @param error
*/
@OnError
public void onError(Session session, Throwable error) {
log.error("WebSocketUserServer 发生错误:"+error);
error.printStackTrace();
}
/*
给客户端发送文本信息
*/
public void sendMessage(String message) throws IOException {
this.session.getBasicRemote().sendText(message);
log.info("WebSocketUserServer sendMessage:"+message);
}
/*
发送用户状态信息
*/
public void sendUserPushMsgInfo(String status) throws IOException{
this.session.getBasicRemote().sendText(status);
log.info("WebSocketUserServer sendUserPushMsgInfo:"+status);
}
/*
根据userID给客户端推送用户状态
*/
public static void PushMsgInfoToUser(String userId,String os
,String businessType,String status) throws IOException {
if(status !=null && !"".equals(status)){
userSockets.stream()
.forEach(u->{
if(u.getUserId().equals(userId)){
try {
u.getWebSocketUserServer().sendUserPushMsgInfo(status);
log.info("WebSocketUserServer PushMsgInfoToUser success,userId:"+userId);
} catch (IOException e) {
e.printStackTrace();
log.error("WebSocketUserServer PushMsgInfoToUser error,userId:"+userId);
}
}
});
}
}
/*
定时检查存活的Session，如果未存活进行处理
*/
@Scheduled(cron = "0 0/2 * * * ?")
public static void checkAliveSession(){
log.info("WebSocketUserServer checkAliveSession start:"+new Date());
userSockets.stream()
.forEach(u->{
if(!u.getWebSocketUserServer().session.isOpen()){
userSockets.remove(u) ;
log.info("WebSocketUserServer checkAlive remove not open session,userId:"+u.getUserId());
}
});
log.info("WebSocketUserServer checkAliveSession end:"+new Date());
}
public static synchronized int getOnlineCount() {
return onlineCount.get();
}
public static synchronized void addOnlineCount() {
WebSocketUserServer.onlineCount.getAndIncrement();
}
public static synchronized void subOnlineCount() {
WebSocketUserServer.onlineCount.getAndDecrement();
}
}二、websocket服务中引入service服务
采用辅助工具类SpringUtil获取Bean,
UcTokenFeign ucTokenFeign = SpringUtil.getBean(UcTokenFeign.class) ;@Component
public class SpringUtil implements ApplicationContextAware {
private static ApplicationContext applicationContext;
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
if(SpringUtil.applicationContext == null) {
SpringUtil.applicationContext = applicationContext;
}
}
//获取applicationContext
public static ApplicationContext getApplicationContext() {
return applicationContext;
}
//通过name获取 Bean.
public static Object getBean(String name){
return getApplicationContext().getBean(name);
}
//通过class获取Bean.
public static <T> T getBean(Class<T> clazz){
return getApplicationContext().getBean(clazz);
}
//通过name,以及Clazz返回指定的Bean
public static <T> T getBean(String name,Class<T> clazz){
return getApplicationContext().getBean(name, clazz);
}
}三、websocket的分布式实现
1.session 放到redis中，实现数据共享，但是websocket session不支持序列号，存储不了
2.加入消息中间件，实现收到消息后的共享
consumer有两种消费模式：集群消费和广播消费。集群消费：多个consumer平均消费该topic下所有mq的消息，即某个消息在某个message queue中被一个consumer消费后，其他消费者就不会消费到它；广播消费：所有consumer可以消费到发到这个topic下的所有消息。
因为Session不支持序列化，nginx分发不能保证一定指定到同一台服务器，特别移动互联网，移动设备下。
故采用消息订阅模式进行实现。每台服务器都订阅相同主题的消息，接收到消息后，关联到session则进行推送消息。
CopyOnWriteArrayList<UserSocket> userSockets = new CopyOnWriteArrayList<>() 这里便是维护关系点四、客户端调用的html测试代码
<!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://127.0.0.1:8877/websocket/user1/qw");
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+ new Date());
} else {
alert("连接没有开启.");
}
}
function userclose(){
if (!window.WebSocket) {
return;
}
if (socket.readyState == WebSocket.OPEN) {
socket.close() ;
} else {
alert("连接没有开启.");
}
}
</script>
<form onsubmit="return false;">
<h3>WebSocket 聊天室1：</h3>
<textarea id="responseText" style="width: 500px; height: 300px;"></textarea>
<br>
<input type="button" onclick="send('first send message')" value="btnSend">
<input type="button" onclick="userclose()" value="btnClose">
</form>
</body>
</html>五、nginx配置
upstream websocket {
server 1.203.115.27:8877;
server 127.0.0.1:8877;
}
server {
listen 8888;
location / {
proxy_pass http://websocket;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
}
}六、zuul负载websocket
spring cloud zuul 1.x版本临时不直接支持spring websocket，到2.×版本会支持。
七、断网、弱网、切换网等场景，实际使用的问题处理
待补充
八、websocket发送消息支持的长度大小
下面代码循环执行50000次，前端还可以接收到，不过已经需要好几秒的时间，这个时间延迟已经不低。
10W次也可以接收到，已经延迟到几分钟的程度。
循环次数 length
10000 33400
20000 66800
50000 16700011
100000 33400011
StringBuffer msg =new StringBuffer() ;
// {"centerLat":"27.403234","centerLon":"117.504426","maxLat":"31.849878","maxLon":"121.434785","minLat":"22.956590","minLon":"113.574066","locations":[{"lon":"121.434785","lat":"31.849878","vehicleNo":"京AA8866","transportStatus":"0"},{"lon":"113.574066","lat":"22.956590","vehicleNo":"京ETYUUII","transportStatus":"0"}]}
for(int i=0;i<100000;i++){
msg.append( " {\"centerLat\":\"27.403234\",\"centerLon\":\"117.504426\",\"maxLat\":\"31.849878\"" +
",\"maxLon\":\"121.434785\",\"minLat\":\"22.956590\",\"minLon\":\"113.574066\"" +
",\"locations\":[{\"lon\":\"121.434785\",\"lat\":\"31.849878\",\"vehicleNo\":\"京AA8866\",\"transportStatus\":\"0\"}" +
",{\"lon\":\"113.574066\",\"lat\":\"22.956590\",\"vehicleNo\":\"京ETYUUII\",\"transportStatus\":\"0\"}]}\n"
);
}
sendMessage("server连接成功;"+msg.toString());九、支持SSL(https)
修改前端websocket连接代码，原本ws://需要改为wss://（购买或）生成密钥和证书，过程省略。需要注意的是：自己生成的证书在很多浏览器上会报警告，忽略后websocket仍然能用，如Chrom、Firefox，但有些浏览器不能用，如Safari。修改/etc/nginx/conf.d/mzsg.conf
upstream cat {
server 172.168.0.2:8080 weight=5;
server 172.168.0.2:7080 weight=5;
}
server {
listen 443;
server_name testsocket;
access_log /data/logs/nginx/test.access.log;
error_log /data/logs/nginx/test.error.log;
ssl on;
ssl_certificate cert/214745699540016.pem;
ssl_certificate_key cert/214745699540016.key;
ssl_session_timeout 5m;
ssl_ciphers ECDHE-RSA-AES128-GCM-SHA256:ECDHE:ECDH:AES:HIGH:!NULL:!aNULL:!MD5:!ADH:!RC4;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_prefer_server_ciphers on;
location / {
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_set_header X-real-ip $remote_addr;
proxy_set_header X-Forwarded-For $remote_addr;
proxy_pass http://10.144.130.86:8877;
}
}
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