1、配置pom.xml
<!-- 增加 websocket-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
2、編寫websocket配置類
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();
}
@Bean
public WebSocketEndpointConfigure newConfigure() {
return new WebSocketEndpointConfigure();
}
}
3、編寫 WebSocketEndpoint配置類
import javax.websocket.server.ServerEndpointConfig; import org.springframework.beans.BeansException; import org.springframework.beans.factory.BeanFactory; import org.springframework.context.ApplicationContext; import org.springframework.context.ApplicationContextAware;
public class WebSocketEndpointConfigure extends ServerEndpointConfig.Configurator implements ApplicationContextAware {
private static volatile BeanFactory context;
@Override
public <T> T getEndpointInstance(Class<T> clazz) throws InstantiationException {
return context.getBean(clazz);
}
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
WebSocketEndpointConfigure.context = applicationContext;
}
}
4、編寫WebSocketServer
import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.stereotype.Component; import javax.websocket.*; import javax.websocket.server.PathParam; import javax.websocket.server.ServerEndpoint; import java.io.IOException; import java.util.ArrayList; import java.util.List; import java.util.concurrent.ConcurrentHashMap;
@Component
@ServerEndpoint(value = "/webSocket/{userId}", configurator = WebSocketEndpointConfigure.class)
public class WebSocketServer {
// ConcurrentHashMap用來存放每個客戶端對應的WebSocketServer對象。
private static ConcurrentHashMap<String,Session> webSocketSet = new ConcurrentHashMap<String, Session>();
private Logger log = LoggerFactory.getLogger(WebSocketServer.class);
/**
* 連接建立成功調用的方法
*/
@OnOpen
public void onOpen(Session session,@PathParam("userId") String userId) {
webSocketSet.put(userId,session);
//相關業務處理，根據拿到的用戶ID判斷其爲那種角色，根據角色ID去查詢是否有需要推送給該角色的消息，有則推送
List<String> totalPushMsgs = new ArrayList<String>();
totalPushMsgs.add("歡迎您:"+ userId);
if(totalPushMsgs != null && !totalPushMsgs.isEmpty()) {
totalPushMsgs.forEach(e -> sendMessage(userId,e));
}
}
public void sendMessage(String userId,String message) {
try {
Session currentSession = webSocketSet.get(userId);
if(currentSession != null){
currentSession.getBasicRemote().sendText(message);
}
log.info("推送消息成功，消息爲：" + message);
} catch (IOException e) {
log.error(e.getMessage());
}
}
/**
* 自定義消息
*/
public static void sendInfo(String userId,String message) throws IOException {
Session currentSession = webSocketSet.get(userId);
if(currentSession != null){
currentSession.getBasicRemote().sendText(message);
}
}
/**
* 用戶退出時，連接關閉調用的方法
*/
public static void onCloseConection(String userId) {
webSocketSet.remove(userId); // 從set中刪除
}
/**
* 連接關閉調用的方法
*/
@OnClose
public void onClose() {
log.info("一個客戶端關閉連接");
}
/**
* 收到客戶端消息後調用的方法
* @param message
* 客戶端發送過來的消息
*/
@OnMessage
public void onMessage(String message, Session session) {
}
/**
* 發生錯誤時調用
*/
@OnError
public void onError(Session session, Throwable error) {
log.error("websocket出現錯誤");
}
}
5、編寫前端代碼
<!DOCTYPE HTML>
<html>
<head>
<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;
//判斷當前瀏覽器是否支持WebSocket
if('WebSocket' in window){
websocket = new WebSocket("ws://localhost:8761/webSocket/111");
}
else{
alert('Not support websocket')
}
//連接發生錯誤的回調方法
websocket.onerror = function(){
setMessageInnerHTML("error");
};
//連接成功建立的回調方法
websocket.onopen = function(event){
setMessageInnerHTML("open");
}
//接收到消息的回調方法
websocket.onmessage = function(event){
setMessageInnerHTML(event.data);
}
//連接關閉的回調方法
websocket.onclose = function(){
setMessageInnerHTML("close");
}
//監聽窗口關閉事件，當窗口關閉時，主動去關閉websocket連接，防止連接還沒斷開就關閉窗口，server端會拋異常。
window.onbeforeunload = function(){
websocket.close();
}
//將消息顯示在網頁上
function setMessageInnerHTML(innerHTML){
document.getElementById('message').innerHTML += innerHTML + '<br/>';
}
//關閉連接
function closeWebSocket(){
websocket.close();
}
//發送消息
function send(){
var message = document.getElementById('text').value;
websocket.send(message);
}
</script>
</html>
6、java後臺只需要
WebSocketServer.sendInfo(userId,"我是後臺消息");
消息會發送到 websocket.onmessage方法上