原文：cnblogs.com/jae-tech/p/15409340.html
复制代码write in front
This exception is not that exception, and the exception mentioned in the title is a business exception.
Recently, I made a request for inspection of fire protection equipment. If an abnormality is found in the inspection, submit it through the mobile phone. The real-time monitoring page in the background obtains the information and location of the equipment in real time, and then arranges employees to deal with it.
Because the server needs to actively send messages to the client, it is easy to think of using WebSocket to achieve this function.
WebSocket will not be introduced, the link is: developer.mozilla.org/zh-CN/docs/…
The front end is slightly complicated, and it is necessary to trace the mouse on a position map to locate each device and render it according to different screen sizes. This article will not introduce it, but simply use the page style for effect presentation. Recommendation: Covers almost all the operations you need in SpringBoot .
Green is normal, red is abnormal
The expected effect, before receiving the request -----> the one with id 3 submitted an exception, and Wang Wu with id 3 turned red
accomplish
front end:
Paste the code directly
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="utf-8" />
5 <title>实时监控</title>
6 </head>
7 <style>
8 .item {
9 display: flex;
10 border-bottom: 1px solid #000000;
11 justify-content: space-between;
12 width: 30%;
13 line-height: 50px;
14 height: 50px;
15 }
16
17 .item span:nth-child(2){
18 margin-right: 10px;
19 margin-top: 15px;
20 width: 20px;
21 height: 20px;
22 border-radius: 50%;
23 background: #55ff00;
24 }
25 .nowI{
26 background: #ff0000 !important;
27 }
28 </style>
29 <body>
30 <div id="app">
31 <div v-for="item in list" class="item">
32 <span>{{item.id}}.{{item.name}}</span>
33 <span :class='item.state==-1?"nowI":""'></span>
34 </div>
35 </div>
36 </body>
37 <script src="./js/vue.min.js"></script>
38 <script type="text/javascript">
39 var vm = new Vue({
40 el: "#app",
41 data: {
42 list: [{
43 id: 1,
44 name: '张三',
45 state: 1
46 },
47 {
48 id: 2,
49 name: '李四',
50 state: 1
51 },
52 {
53 id: 3,
54 name: '王五',
55 state: 1
56 },
57 {
58 id: 4,
59 name: '韩梅梅',
60 state: 1
61 },
62 {
63 id: 5,
64 name: '李磊',
65 state: 1
66 },
67 ]
68 }
69 })
70
71 var webSocket = null;
72 if ('WebSocket' in window) {
73 //创建WebSocket对象
74 webSocket = new WebSocket("ws://localhost:18801/webSocket/" + getUUID());
75
76 //连接成功
77 webSocket.onopen = function() {
78 console.log("已连接");
79 webSocket.send("消息发送测试")
80 }
81 //接收到消息
82 webSocket.onmessage = function(msg) {
83 //处理消息
84 var serverMsg = msg.data;
85 var t_id = parseInt(serverMsg) //服务端发过来的消息，ID，string需转化为int类型才能比较
86 for (var i = 0; i < vm.list.length; i++) {
87 var item = vm.list[i];
88 if(item.id == t_id){
89 item.state = -1;
90 vm.list.splice(i,1,item)
91 break;
92 }
93 }
94 };
95
96 //关闭事件
97 webSocket.onclose = function() {
98 console.log("websocket已关闭");
99 };
100 //发生了错误事件
101 webSocket.onerror = function() {
102 console.log("websocket发生了错误");
103 }
104 } else {
105 alert("很遗憾，您的浏览器不支持WebSocket！")
106 }
107
108 function getUUID() { //获取唯一的UUID
109 return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
110
111 var r = Math.random() * 16 | 0,
112 v = c == 'x' ? r : (r & 0x3 | 0x8);
113 return v.toString(16);
114 });
115 }
116 </script>
117 </html>
复制代码rear end:
The project structure is like this, the following code key comments are all there, so I will not repeat the description.
1. Create a new SpringBoot project and select web and WebSocket dependencies
2. Configure application.yml
#端口
server:
port: 18801
#密码，因为接口不需要权限，所以加了个密码做校验
mySocket:
myPwd: jae_123
复制代码3. WebSocketConfig configuration class
1 @Configuration
2 public class WebSocketConfig {
3
4 /**
5 * 注入一个ServerEndpointExporter,该Bean会自动注册使用@ServerEndpoint注解申明的websocket endpoint
6 */
7 @Bean
8 public ServerEndpointExporter serverEndpointExporter(){
9 return new ServerEndpointExporter();
10 }
11 }
复制代码4, WebSocketServer class, used for interaction between server and client
1 /**
2 * @author jae
3 * @ServerEndpoint("/webSocket/{uid}") 前端通过此URI与后端建立链接
4 */
5
6 @ServerEndpoint("/webSocket/{uid}")
7 @Component
8 public class WebSocketServer {
9
10 private static Logger log = LoggerFactory.getLogger(WebSocketServer.class);
11
12 //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。
13 private static final AtomicInteger onlineNum = new AtomicInteger(0);
14
15 //concurrent包的线程安全Set，用来存放每个客户端对应的WebSocketServer对象。
16 private static CopyOnWriteArraySet<Session> sessionPools = new CopyOnWriteArraySet<Session>();
17
18 /**
19 * 有客户端连接成功
20 */
21 @OnOpen
22 public void onOpen(Session session, @PathParam(value = "uid") String uid){
23 sessionPools.add(session);
24 onlineNum.incrementAndGet();
25 log.info(uid + "加入webSocket！当前人数为" + onlineNum);
26 }
27
28 /**
29 * 连接关闭调用的方法
30 */
31 @OnClose
32 public void onClose(Session session) {
33 sessionPools.remove(session);
34 int cnt = onlineNum.decrementAndGet();
35 log.info("有连接关闭，当前连接数为：{}", cnt);
36 }
37
38 /**
39 * 发送消息
40 */
41 public void sendMessage(Session session, String message) throws IOException {
42 if(session != null){
43 synchronized (session) {
44 session.getBasicRemote().sendText(message);
45 }
46 }
47 }
48
49 /**
50 * 群发消息
51 */
52 public void broadCastInfo(String message) throws IOException {
53 for (Session session : sessionPools) {
54 if(session.isOpen()){
55 sendMessage(session, message);
56 }
57 }
58 }
59
60 /**
61 * 发生错误
62 */
63 @OnError
64 public void onError(Session session, Throwable throwable){
65 log.error("发生错误");
66 throwable.printStackTrace();
67 }
68
69 }
复制代码5. WebSocketController class for interface testing
1 @RestController
2 @RequestMapping("/open/socket")
3 public class WebSocketController {
4
5 @Value("${mySocket.myPwd}")
6 public String myPwd;
7
8 @Autowired
9 private WebSocketServer webSocketServer;
10
11 /**
12 * 手机客户端请求接口
13 * @param id 发生异常的设备ID
14 * @param pwd 密码（实际开发记得加密）
15 * @throws IOException
16 */
17 @PostMapping(value = "/onReceive")
18 public void onReceive(String id,String pwd) throws IOException {
19 if(pwd.equals(myPwd)){ //密码校验一致（这里举例，实际开发还要有个密码加密的校验的），则进行群发
20 webSocketServer.broadCastInfo(id);
21 }
22 }
23
24 }
复制代码test
1. Open the front-end page and make a WebSocket connection
console output, the connection is successful
2. Because it is simulated data, all displays are normal, and there is no page rendering during abnormal submission.
3. Next, we use the interface testing tool Postman to submit an exception
Note the state change of this data with id 3
We can see that the status of Wang Wu with id 3 has become abnormal, and the real-time communication is successful.
Reference: developer.mozilla.org/en-US/docs/…
Recommended: Covers almost all the operations you need in SpringBoot
at last
There is a need for real-time monitoring in this aspect of work, you can refer to it.