查看Socket断开原因及加入心跳机制防止自动断开连接

map $http_upgrade $connection_upgrade {
    default upgrade;
    '' close;
}
location / {
    proxy_pass https://socket;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $connection_upgrade;
}

ws.onclose = function (ev) {
  console.log('socket 断开: ' + ev.code + ' ' + ev.reason + ' ' + ev.wasClean)
}

var lockReconnect = false;  
var ws = null;          
var wsUrl = 'wss://127.0.0.1/socket'
createWebSocket(wsUrl);  

function createWebSocket(url) {
    try{
        if('WebSocket' in window){
            ws = new WebSocket(url);
        }
        initEventHandle();
    }catch(e){
        reconnect(url);
        console.log(e);
    }     
}

function initEventHandle() {
    ws.onclose = function (ev) {
        reconnect(wsUrl);
         console.log('socket 断开: ' + ev.code + ' ' + ev.reason + ' ' + ev.wasClean)
    };
    ws.onerror = function (ev) {
        reconnect(wsUrl);
        console.log("llws连接错误!");
    };
    ws.onopen = function () {
        heartCheck.reset().start();      
        console.log("llws连接成功!"+new Date().toLocaleString());
    };
    ws.onmessage = function (message) {    
        heartCheck.reset().start();      //拿到任何消息都说明当前连接是正常的
        console.log("llws收到消息啦:" +message.data);
        if(message.data!='pong'){
            var msg = JSON.parse(message.data);
        }
    };
}

// 当窗口关闭时，主动去关闭websocket连接
window.onbeforeunload = function() {
    ws.close();
}  

function reconnect(url) {
    if(lockReconnect) return;
    lockReconnect = true;
    setTimeout(function () {     //没连接上会一直重连，设置延迟避免请求过多
        createWebSocket(url);
        lockReconnect = false;
    }, 2000);
}
 
var heartCheck = {
    timeout: 3000,       
    timeoutObj: null,
    serverTimeoutObj: null,
    reset: function(){
        clearTimeout(this.timeoutObj);
        clearTimeout(this.serverTimeoutObj);
        return this;
    },
    start: function(){
        var self = this;
        this.timeoutObj = setTimeout(function(){ 
            ws.send("ping");
            console.log("ping!")
            self.serverTimeoutObj = setTimeout(function(){
              //如果超过一定时间还没重置，说明后端主动断开了
                ws.close();      
            }, self.timeout)
        }, this.timeout)
    }
}

@OnMessage  
public void onMessage(String message, Session session) {  
        if(message.equals("ping")){

        }else{
               
        }
}