The original intention of using WebSocket is to update the alarm information in MySQL to the Web page display in real time.
Not how to touch the Web, the code is really rotten, but also is a function of implementation, put here is also spur themselves, the web will be more effort
Introducing Dependencies
<dependency> <groupId>Mysql</groupId> <artifactid>Mysql-connector-java</artifactid> <version>5.1.38</version> </Dependency> <dependency> <groupId>Javax</groupId> <artifactid>Javaee-api</artifactid> <version>7.0</version> <scope>Provided</Scope> </Dependency>First look at the format of the data in MySQL
Data encapsulation
Public classAlarmmessage {PrivateString Fanno;PrivateString time;PrivateString description; Public Alarmmessage(String Fanno, String time, string description) { This. Fanno = Fanno; This. Time = time; This. Description = description; } PublicStringGetfanno() {returnFanno; } PublicStringGetTime() {returnTime } PublicStringgetdescription() {returnDescription }}JDBC reads data from the database
PublicClass Dbutil { Public List<Alarmmessage>Getfromdb () throws SQLException, ClassNotFoundException, Illegalaccessexception, instantiationexception {List<Alarmmessage> List=NewArrayList<Alarmmessage>();StringDirver="Com.mysql.jdbc.Driver";StringUser="Root";StringPsd="Root";StringDatabase="Streamingproblem";StringTableName="Problem";StringUrl="jdbc:mysql://172.17.11.120:3306/"+Database+"? user="+User+"&password="+Psd Class.Forname (Dirver).Newinstance (); Connection Conn=DriverManager.getconnection (URL); Statement Stat=Conn.Createstatement ();StringSql="SELECT * from"+TableNameResultSetRs=Stat.ExecuteQuery (SQL); while(RS.Next ()) {Alarmmessage alarmmessage=NewAlarmmessage (RS.GetString (2), RS.GetString (3), RS.GetString (4));List.Add (Alarmmessage); } RS.Close (); Stat.Close (); Conn.Close ();return List; }}Write a thread to send new data to the page, run to open an infinite loop, with a variable currentindex record the current amount of data, when there is new data, send new data
ImportJavax.websocket.Session; Public class onethread extends Thread { PrivateSession session;PrivateList<alarmmessage> Currentmessage;PrivateDbutil Dbutil;Private intCurrentindex; Public Onethread(Session session) { This. session = Session; Currentmessage =NewArraylist<alarmmessage> (); Dbutil =NewDbutil (); Currentindex =0;//This is 0 messages}@Override Public void Run() { while(true) {List<alarmmessage> List =NULL;Try{Try{list = Dbutil.getfromdb (); }Catch(ClassNotFoundException e) {E.printstacktrace (); }Catch(Illegalaccessexception e) {E.printstacktrace (); }Catch(Instantiationexception e) {E.printstacktrace (); } }Catch(SQLException e) {E.printstacktrace (); }if(List! =NULL&& Currentindex < List.size ()) { for(inti = Currentindex; I < list.size (); i++) {Try{session.getbasicremote (). SendText (List.get (i). Getfanno () +","+ List.get (i). GetTime () +","+ List.get (i). GetDescription ());//Session.getbasicremote (). SendObject (List.get (i));//no encoder specified for object of C Lass [Class Alarmmessage]}Catch(IOException e) {E.printstacktrace (); }} Currentindex = List.size (); }Try{//One second to refresh onceThread.Sleep ( +); }Catch(Interruptedexception e) {E.printstacktrace (); } } }}To start the Send data thread in OnOpen
JS Implementation WebSocket Clientimport javax.websocket.OnOpen;import javax.websocket.Session;import javax.websocket.server.ServerEndpoint;@ServerEndpoint("/websocket")publicclass websocket { @OnOpen publicvoidonOpen(Session session){ OneThread thread =null; thread=new OneThread(session); thread.start(); }}
<%@ page import="java.sql.*" %><html><head> <script type="Text/javascript"> //test can be run up, can not connect, automatically push data, do not do the data display //client will connect to the server varWebSocket =NewWebSocket ("Ws://localhost:8081/websocket");//This is just for debugging //callback when connection failsWebsocket.onerror = function (event) {Makedataonweb ("Error"); };//This is just for debugging //When the connection succeeds, the code in parentheses is really executed! Websocket.onopen = function (event) {Makedataonweb ("Conn Success"); }; Websocket.onmessage = function (event) {Makedataonweb (Event.data); };//This is just for debuggingWebsocket.onclose = function (event) {Makedataonweb ("Conn Close"); }; function makedataonweb(data) { varA = data;varDivnode = document.getElementById ("View");varLiNode = Document.createelement ("Li"); linode.innerhtml = A; Divnode.appendchild (LiNode);//Divnode.insertbefore (LiNode, divnode.children[0]); //can't use InsertAfter, it doesn't seem to work that way. //var Divnode = document.getElementById ("view");//var Trnode = document.createelement ("tr");//var TD1 = document.createelement ("TD");//var TD2 = document.createelement ("TD");//var td3 = document.createelement ("TD");//td1.innerhtml = A;//td2.innerhtml = A;//td3.innerhtml = A;//Trnode.appendchild (TD1)//Trnode.appendchild (TD2)//Trnode.appendchild (TD3) //var head = document.getElementById ("Head");//document.write (A + "<br>");//Direct Write//Document.getelementsbyid ("a"). Innerhtml= "FADFADFA";//do not output any content};</script></head><body><% @page contenttype="text/html; UTF8 " %><% @page language="java" %><% @page import="java.sql.*" %><% @page pageencoding="UTF-8" %><!--solve Chinese characters --<div id="View"></div></body></html>WebSocket update MySQL data to the page in real time
Start building with 50+ products and up to 12 months usage for Elastic Compute Service
1 on 1 presale consultation
24/7 Technical Support 6 Free Tickets per Quarter Faster Response
Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.
A comprehensive suite of global cloud computing services to power your business
Payment Methods We Support
