写在前面
需求: 项目测试, 缺少用户登录失败给admin推送消息, 想到这个方式, 当用户登录失败时, admin用户会在页面看到咣咣乱弹的alert.
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("已连接");
} @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("给所有人");
}
} @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; // 获得当前登录人员的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连接发生错误的回调方法
websocket.onerror = function () {
setMessageInnerHTML("WebSocket连接发生错误");
}; //WebSocket连接成功建立的回调方法
websocket.onopen = function () {
setMessageInnerHTML("WebSocket连接成功");
}; //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连接，防止连接还没断开就关闭窗口，server端会抛异常。
window.onbeforeunload = function () {
closeWebSocket();
}; //关闭WebSocket连接
function closeWebSocket() {
websocket.close();
} //连接关闭的回调方法
websocket.onclose = function () {
setMessageInnerHTML("WebSocket连接关闭");
}; //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录!");
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();
}