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服务器之家。

原文链接：https://blog.csdn.net/zwl18210851801/article/details/87931653