WebSocket实现数据库更新时前端页面刷新_Java教程

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：

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									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：

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									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：

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									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：

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									@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：

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									<dependency>

									 <groupid>org.springframework</groupid>

									 <artifactid>spring-websocket</artifactid>

									</dependency>