写在前面
需求: 项目测试, 缺乏用户登陆失败给admin推送消息, 想到这个方式, 当用户登陆失败时, admin用户会在页面看到咣咣乱弹的alert. html
正文
pom.xml
<!-- webSocket 开始--> <dependency> <groupId>javax.websocket</groupId> <artifactId>javax.websocket-api</artifactId> <version>1.1</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax</groupId> <artifactId>javaee-api</artifactId> <version>7.0</version> <scope>provided</scope> </dependency> <!-- webSocket 结束-->
Websocket.java
package com.jeecg.webSocket; import net.sf.json.JSONObject; import javax.websocket.*; import javax.websocket.server.PathParam; import javax.websocket.server.ServerEndpoint; import java.io.IOException; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; @ServerEndpoint("/webSocket/{username}") public class WebSocket { private static int onlineCount = 0; private static Map<String, WebSocket> clients = new ConcurrentHashMap<String, WebSocket>(); private Session session; private String username; @OnOpen public void onOpen(@PathParam("username") String username, Session session) throws IOException { this.username = username; this.session = session; addOnlineCount(); clients.put(username, this); System.out.println("已链接"); } @OnClose public void onClose() throws IOException { clients.remove(username); subOnlineCount(); } @OnMessage public void onMessage(String message) throws IOException { JSONObject jsonTo = JSONObject.fromObject(message); String mes = (String) jsonTo.get("message"); if (!jsonTo.get("To").equals("All")){ sendMessageTo(mes, jsonTo.get("To").toString()); }else{ sendMessageAll("给全部人"); } } @OnError public void onError(Session session, Throwable error) { error.printStackTrace(); } public void sendMessageTo(String message, String To) throws IOException { for (WebSocket item : clients.values()) { if (item.username.equals(To) ) item.session.getAsyncRemote().sendText(message); } } public void sendMessageAll(String message) throws IOException { for (WebSocket item : clients.values()) { item.session.getAsyncRemote().sendText(message); } } public static synchronized int getOnlineCount() { return onlineCount; } public static synchronized void addOnlineCount() { WebSocket.onlineCount++; } public static synchronized void subOnlineCount() { WebSocket.onlineCount--; } public static synchronized Map<String, WebSocket> getClients() { return clients; } }
fineui_home.jsp
<script>
var websocket = null; var host = document.location.host; // 得到当前登陆人员的userName
var username = '${loginUserName}'; // 获取项目名
var webName = '${webName}'; //判断当前浏览器是否支持WebSocket
if ('WebSocket' in window) { // 浏览器支持Websocket
websocket = new WebSocket('ws://' + host + '/' + webName + '/webSocket/' + username); } else { // 浏览器 Not support websocket
} //WebSocket链接发生错误的回调方法
websocket.onerror = function () { setMessageInnerHTML("WebSocket链接发生错误"); }; //WebSocket链接成功创建的回调方法
websocket.onopen = function () { setMessageInnerHTML("WebSocket链接成功"); }; //接收到消息的回调方法
websocket.onmessage = function (event) { alertTip(event.data); // websocket.close();
// alert("webSocket已关闭！")
}; //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket链接，防止链接还没断开就关闭窗口，server端会抛异常。
window.onbeforeunload = function () { closeWebSocket(); }; //关闭WebSocket链接
function closeWebSocket() { websocket.close(); } //链接关闭的回调方法
websocket.onclose = function () { setMessageInnerHTML("WebSocket链接关闭"); }; //将消息显示在网页上
function setMessageInnerHTML(innerHTML) { // document.getElementById('message').innerHTML += innerHTML + '<br/>';
} </script>
业务调用
WebSocket ws = new WebSocket(); JSONObject jo = new JSONObject(); jo.put("message", "这个比密码不对还想登陆!"); jo.put("To", "admin");// 给用户名为admin的用户推送 try { ws.onMessage(jo.toString()); } catch (IOException e) { e.printStackTrace(); }