WebSocket实现数据库更新时前端页面刷新

本文实例为大家分享了WebSocket实现数据库更新时前端页面刷新，供大家参考，具体内容如下

后台代码：

WebSocketConfig：

package com.x.common.websocket;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

@Configuration
public class WebSocketConfig {
 @Bean
 public ServerEndpointExporter serverEndpointExporter() {
 return new ServerEndpointExporter();
 }
}

WebSocketServlet：

package com.x.common.websocket;
import com.alibaba.fastjson.JSONObject;
import org.springframework.stereotype.Component;

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;

@ServerEndpoint("/websocket/{userId}")
@Component
public class WebSocketServlet {

 private static int onlineCount = 0;
 private static Map<String, WebSocketServlet> clients = new ConcurrentHashMap<>();
 private Session session;
 private String userId;

 @OnOpen
 public void onOpen(@PathParam("userId") String userId, Session session) throws IOException {

 this.userId = userId;
 this.session = session;

 addOnlineCount();
 clients.put(userId, this);
 System.out.println("已连接");
 }

 @OnClose
 public void onClose() throws IOException {
 clients.remove(userId);
 subOnlineCount();
 }

 @OnMessage
 public void onMessage(String message) throws IOException {

 JSONObject jsonTo = JSONObject.parseObject(message);

 if (!jsonTo.get("To").equals("All")){
 sendMessageTo("给一个人", 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 {
 // session.getBasicRemote().sendText(message);
 //session.getAsyncRemote().sendText(message);
 for (WebSocketServlet item : clients.values()) {
 if (item.userId.equals(To) ){
 item.session.getAsyncRemote().sendText(message);
 }
 }
 }

 public void sendMessageAll(String message) throws IOException {
 for (WebSocketServlet item : clients.values()) {
 item.session.getAsyncRemote().sendText(message);
 }
 }

 public static synchronized int getOnlineCount() {
 return onlineCount;
 }

 public static synchronized void addOnlineCount() {
 WebSocketServlet.onlineCount++;
 }

 public static synchronized void subOnlineCount() {
 WebSocketServlet.onlineCount--;
 }

 public static synchronized Map<String, WebSocketServlet> getClients() {
 return clients;
 }
}

JS代码：

var websocket = null;

//判断当前浏览器是否支持WebSocket
if ('WebSocket' in window) {
 websocket = new WebSocket("ws://localhost:8086/websocket/1");
} else {
 alert('当前浏览器 Not support websocket')
}

//连接发生错误的回调方法
websocket.onerror = function() {
 console.log("WebSocket连接发生错误");
};

//连接成功建立的回调方法
websocket.onopen = function() {
 console.log("WebSocket连接成功");
}

//接收到消息的回调方法
websocket.onmessage = function(event) {
 //返回数据转JSON
 var json=JSON.parse(event.data);
 //result为bootstrap table 返回数据
 var rows=result.rows;
 for(var i=0;i<rows.length;i++){
 var row=rows[i];
 if(row.id==json.id){
 //判断列Id相同时刷新表格
 //$('#dataGrid').bootstrapTable('updateByUniqueId', {index: i, row: row});'refresh'
 $('#dataGrid').bootstrapTable('refresh');
 }
 }
 console.log(event.data);
}

//连接关闭的回调方法
websocket.onclose = function() {
 console.log("WebSocket连接关闭");
}

//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();
}

返回前台是调用方法：

@Autowired
private WebSocketServlet scoket;

//学生信息
XStudentInfoEntity student = xStudentInfoService.getObjectById(id.replace("\"",""));
//提醒学生数据发生改变
scoket.sendMessageAll(JSONObject.toJSONString(student));

pom.xml：

<dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-websocket</artifactId>
</dependency>

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。