springboot2.3版本使用websocket并访问数据库
1.配置文件WebSocketConfig
package com.example.demo.config;
import com.example.demo.service.TestService;
import com.example.demo.service.WebSocketServer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;
@Configuration
public class WebSocketConfig {
/**
* ServerEndpointExporter 作用
* 这个Bean会自动注册使用@ServerEndpoint注解声明的websocket endpoint
* @return
*/
@Bean
public ServerEndpointExporter serverEndpointExporter() {
System.out.println("WebSocketConfig被注入了");
return new ServerEndpointExporter();
}
@Autowired
public void setTestService(TestService testService){
WebSocketServer.testService=testService;
}
}
setTestService函数是用来获得service层的对象，可以调用testService的函数查询数据库的信息
2.WebSocketServer
package com.example.demo.service;
import org.apache.commons.lang.StringUtils;
import org.springframework.stereotype.Component;
import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
@ServerEndpoint("/server/{userId}")
@Component
public class WebSocketServer {
//websocket需要定义为static
public static TestService testService;
/**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。*/
private static int onlineCount = 0;
/**concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。*/
private static ConcurrentHashMap<String,WebSocketServer> webSocketMap = new ConcurrentHashMap<>();
/**与某个客户端的连接会话，需要通过它来给客户端发送数据*/
private Session session;
/**接收userId*/
private String userId="";
/**
* 连接建立成功调用的方法*/
@OnOpen
public void onOpen(Session session,@PathParam("userId") String userId) throws IOException {
this.session = session;
this.userId=userId;
if(webSocketMap.containsKey(userId)){
webSocketMap.remove(userId);
webSocketMap.put(userId,this);
//加入set中
}else{
webSocketMap.put(userId,this);
//加入set中
addOnlineCount();
//在线数加1
}
// sendMessageByTime();
System.out.println(("用户连接:" + userId + ",当前在线人数为:" + getOnlineCount()));
try {
sendMessage("连接成功");
} catch (IOException e) {
System.out.println(("用户:" + userId + ",网络异常!!!!!!"));
}
}
/**
* 连接关闭调用的方法
*/
@OnClose
public void onClose() {
if(webSocketMap.containsKey(userId)){
webSocketMap.remove(userId);
//从set中删除
subOnlineCount();
}
System.out.println(("用户退出:" + userId + ",当前在线人数为:" + getOnlineCount()));
}
/**
* 收到客户端消息后调用的方法
*
* @param message 客户端发送过来的消息*/
@OnMessage
public void onMessage(String message, Session session) {
System.out.println(("用户消息:" + userId + ",报文:" + message));
//可以群发消息
//消息保存到数据库、redis
// if(StringUtils.isNotBlank(message)){
// try {
// //解析发送的报文
// JSONObject jsonObject = JSON.parseObject(message);
// //追加发送人(防止串改)
// jsonObject.put("fromUserId",this.userId);
// String toUserId=jsonObject.getString("toUserId");
// //传送给对应toUserId用户的websocket
// if(StringUtils.isNotBlank(toUserId)&&webSocketMap.containsKey(toUserId)){
// webSocketMap.get(toUserId).sendMessage(jsonObject.toJSONString());
// }else{
// log.error("请求的userId:"+toUserId+"不在该服务器上");
// //否则不在这个服务器上，发送到mysql或者redis
// }
// }catch (Exception e){
// e.printStackTrace();
// }
// }
}
/**
*
* @param session
* @param error
*/
@OnError
public void onError(Session session, Throwable error) {
System.out.println(("用户错误:" + this.userId + ",原因:" + error.getMessage()));
error.printStackTrace();
}
/**
* 实现服务器主动推送
*/
public void sendMessage(String message) throws IOException {
this.session.getBasicRemote().sendText(message);
System.out.println("服务器发送的消息="+message);
}
/**
* 数据库中更改后发送消息
* */
public static void sendInfo(String message,@PathParam("userId") String userId) throws IOException {
System.out.println(("发送消息到:" + userId + "，报文:" + message));
if(StringUtils.isNotBlank(userId)&&webSocketMap.containsKey(userId)){
webSocketMap.get(userId).sendMessage(message);
}else{
System.out.println(("用户" + userId + ",不在线！"));
}
}
public static synchronized int getOnlineCount() {
return onlineCount;
}
public static synchronized void addOnlineCount() {
WebSocketServer.onlineCount++;
}
public static synchronized void subOnlineCount() {
WebSocketServer.onlineCount--;
}
}
这里service层的对象不用加@Autowired注解了
3.写一个网页测试一下
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>My WebSocket</title>
</head>
<body>
Welcome<br/>
<input id="text" type="text" /><button onclick="send()">Send</button>
<button onclick="closeWebSocket()">Close</button>
<div id="message">
</div>
</body>
<script type="text/javascript">
var websocket = null;
//判断当前浏览器是否支持WebSocket ,主要此处要更换为自己的地址
if('WebSocket' in window){
websocket = new WebSocket("ws://192.168.31.188:3306/server/111");
}
else{
alert('Not support websocket')
}
//连接发生错误的回调方法
websocket.onerror = function(){
setMessageInnerHTML("error");
};
//连接成功建立的回调方法
websocket.onopen = function(event){
setMessageInnerHTML("open");
}
//接收到消息的回调方法
websocket.onmessage = function(event){
setMessageInnerHTML(event.data);
}
//连接关闭的回调方法
websocket.onclose = function(){
setMessageInnerHTML("close");
}
//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(){
websocket.close();
}
//将消息显示在网页上
function setMessageInnerHTML(innerHTML){
document.getElementById('message').innerHTML += innerHTML + '
';
}
//关闭连接
function closeWebSocket(){
websocket.close();
}
//发送消息
function send(){
var message = document.getElementById('text').value;
websocket.send(message);
}
</script>
</html>
现在就连接成功了
4.实现客户端更改了信息后服务器将数据库的信息发给客户端
package com.example.demo.controller;
import com.example.demo.entity.Test;
import com.example.demo.service.TestService;
import com.example.demo.service.WebSocketServer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.io.IOException;
import java.util.List;
@RestController
@RequestMapping("/test")
public class TestController {
@Autowired
TestService testService;
@GetMapping("/findAll")
List<Test> findAll(){
return testService.findAll();
}
@PutMapping("updateTest")
int updateTest(@ModelAttribute Test test) throws IOException {
System.out.println("要修改的信息为"+test.toString());
//更改数据库的信息
testService.update(test);
//服务器向客户端发消息
WebSocketServer.sendInfo(testService.findAll().toString(),"111");
return 1;
}
}
调用updateTest接口更改信息后，数据库的信息就返回给客户端了