websocket使用

兼容性介绍 ： https://caniuse.com/#search=websockets

var websocket = null; //判断当前浏览器是否支持WebSocketif (‘WebSocket‘ in window) { ???//websocket = new WebSocket("ws://192.168.1.58:8080/plant/servlet/PushMessage"); ???websocket = new WebSocket("ws://" + $("#webSocketIp").val() + ":" + $("#webSocketPort").val() + "/plant/servlet/PushMessage");}else { ???alert(‘Not support websocket‘)} //连接发生错误的回调方法websocket.onerror = function () { }; //连接成功建立的回调方法websocket.onopen = function (event) { }; //接收到消息的回调方法websocket.onmessage = function (event) { ???var message = eval("(" + event.data + ")");//转换后的JSON对象 ???// ?alert(obj.name);//json name ???var url = window.location.href; ???switch (message.header) { ???????case "nodeOffline": ???????????if (message.concentId == $("#concentId").val()) { ???????????????$("#onlineState").attr("src", "images/photos/offline.png"); ???????????} ???????????updateConcentLogs(message); ???????????break; ???????case "nodeOnline": ???????????if (message.concentId == $("#concentId").val()) { ???????????????$("#onlineState").attr("src", "images/photos/online.png"); ???????????} ???????????updateConcentLogs(message); ???????????break; ???????case "sensorAlarm": ???????????if (message.regionId == regionId) { ???????????????updateSensorAlarm(message); ???????????} ???????????break; ???????case "sensorCurrentData": ???????????if (message.schemeId == schemeId) { ???????????????if(url.indexOf("main")>0){ ???????????????????drawCurrentData(message); ???????????????} ???????????????if(url.indexOf("monitor")>0){ ???????????????????changeCurrentData(message); ???????????????} ????????????} ???????????break; ???????case "deviceSwitchOperate": ???????????//ionic对设备开关操作的推送 ???????????if (nodeId == message.nodeId) { ???????????????//如果当前显示界面显示的为推送过来的设备的开关状态，则改变其状态 ???????????????switchState = message.switchState; ???????????????$("#deviceRow img").attr("src", switchState ? "images/photos/switchOn.png" : "images/photos/switchOff.png"); ???????????} ???????????break; ???????case "lampSwitchOperate": ???????????//ionic对植物灯开关操作的推送 ???????????if (nodeId == message.nodeId) { ???????????????//如果当前显示界面显示的为推送过来的植物灯的开关状态，则改变其状态 ???????????????switchState = message.switchState; ???????????????$("#lampRow img").attr("src", switchState ? "images/photos/switchOn.png" : "images/photos/switchOff.png"); ???????????} ???????????break; ???}} //连接关闭的回调方法websocket.onclose = function () { } //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。window.onbeforeunload = function () { ???websocket.close();} ?//关闭连接function closeWebSocket() { ???websocket.close();} //发送消息function send() { ???var message = document.getElementById(‘text‘).value; ???websocket.send(message);} function formatEventType(concentEventType) { ???var eventType = ‘‘; ???switch (concentEventType) { ???????case "ON_LINE": ???????????eventType = "上线"; ???????????break; ???????case "OFF_LINE": ???????????eventType = "下线"; ???????????break; ???} ???return eventType;} function updateConcentLogs(message) { ???var timeItems = $("#concentLogs").find("div[class=‘time-item‘]"); ???if (timeItems.length > 0) { ???????var newFirst = "" + ???????????"<div class=‘time-item‘ >" + ???????????"<div class=‘item-info‘>" + ???????????"<small class=‘text-muted‘>" + ???????????message.createTime + ???????????"</small> " + ???????????"<p><strong><a href=‘#‘ class=‘text-info‘>" + message.concentName + "</a></strong>" + ???????????formatEventType(message.concentEventType) + ???????????"</p> " + ???????????"</div>" + ???????????"</div>"; ???????$(timeItems[0]).before(newFirst); ???????$(timeItems[timeItems.length - 1]).remove(); ???}} function updateSensorAlarm(message) { ???var timeItems = $("#sensorAlarm a"); ???if (timeItems.length > 0) { ???????var newFirst = "<a href=‘#‘ class=‘dropdown-item notify-item‘>" + ???????????"<div class=‘notify-icon bg-success‘><i class=‘icon-notebook‘></i></div>" + ???????????"<p class=‘notify-details‘>" + message.content + ???????????"<small class=‘text-muted‘>" + message.createTime + "</small>" + ???????????"</p>" + ???????????"</a>"; ???????$(timeItems[0]).before(newFirst); ???????$(timeItems[timeItems.length - 1]).remove(); ???} ???$("#alarmNotice").removeAttr("hidden")}

package net.microlinktech.plant.web.servlet; import org.apache.log4j.Logger; import javax.websocket.*;import javax.websocket.server.ServerEndpoint;import java.util.concurrent.CopyOnWriteArraySet; ?@ServerEndpoint("/servlet/PushMessage")public class PushWebSocketServlet { ????private static Logger logger = Logger.getLogger(PushWebSocketServlet.class); ????// 静态变量，用来记录当前在线连接数。 ???private static volatile int onlineCount = 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 CopyOnWriteArraySet<PushWebSocketServlet> webSocketSet = new CopyOnWriteArraySet<>(); ????// 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; ????/** ????* 连接建立成功调用的方法 ????* ????* @param session 可选的参数。session为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 ????*/ ???@OnOpen ???public void onOpen(Session session) { ???????this.session = session; ???????webSocketSet.add(this); ????//加入set中 ???????addOnlineCount(); ??????????//在线数加1 ???????logger.info("有新连接加入！当前在线客户端为" + getOnlineCount()); ???} ????/** ????* 连接关闭调用的方法 ????*/ ???@OnClose ???public void onClose() { ???????webSocketSet.remove(this); ?//从set中删除 ???????subOnlineCount(); ??????????//在线数减1 ????????logger.info("有一连接关闭！当前在线客户端为" + getOnlineCount()); ???} ????@OnMessage ???public void onMessage (String txt, Session session) { ???????System.out.println("onMessage: " + txt.toUpperCase()); ???} ????/** ????* 发生错误时调用 ????* ????* @param session ????* @param error ????*/ ???@OnError ???public void onError(Session session, Throwable error) { ???????logger.error("发生错误", error); ???} ????/** ????* 发送消息到客户端 ????* ????* @param message ????*/ ???public void sendMessage(String message) {// ???????this.session.getBasicRemote().sendText(message); ???????this.session.getAsyncRemote().sendText(message); ???} ????/** ????* 群发消息 ????* ????* @param message ????*/ ???public static void pushMessage(String message) { ???????for (PushWebSocketServlet item : webSocketSet) { ???????????item.sendMessage(message); ???????} ???} ????public static synchronized int getOnlineCount() { ???????return onlineCount; ???} ????public static synchronized void addOnlineCount() { ???????onlineCount++; ???} ????public static synchronized void subOnlineCount() { ???????onlineCount--; ???}}