maven依赖如下：
maven依赖如下：
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-websocket</artifactId>
<version>2.0.4.RELEASE</version>
</dependency>
1、控制类
package com.boot.river.websocket;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.socket.TextMessage;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
@Controller
@RequestMapping(value = "/websocket", method = {RequestMethod.POST, RequestMethod.GET})/*GET请求开放用于测试，最好只允许POST请求*/
public class WebSocketController {
@Autowired
SpringWebSocketHandler springWebSocketHandler;
/**
* 登录将username放入session中，然后在拦截器HandshakeInterceptor中取出
*/
@ResponseBody
@RequestMapping("/login")
public String login(HttpServletRequest request, @RequestParam(value = "username") String username, @RequestParam(value = "password") String password) {
System.out.println("登录：" + username + "：" + password);
HttpSession session = request.getSession();
if (null != session) {
session.setAttribute("SESSION_USERNAME", username);
return "success";
} else {
return "fail";
}
}
/**
* 指定发送
*/
@ResponseBody
@RequestMapping("/sendToUser")
public String send(@RequestParam(value = "username") String username, @RequestParam(value = "info") String info) {
springWebSocketHandler.sendMessageToUser(username, new TextMessage(info));
System.out.println("发送至：" + username);
return "success";
}
/**
* 广播
*/
@ResponseBody
@RequestMapping("/broadcast")
public String broadcast(@RequestParam(value = "info") String info) {
springWebSocketHandler.sendMessageToUsers(new TextMessage("广播消息：" + info));
System.out.println("广播成功");
return "success";
}
}
2、配置类（实现WebSocketConfigurer接口 ）
@Configuration
@EnableWebSocket
public class SpringWebSocketConfig implements WebSocketConfigurer {
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
registry.addHandler(getSpringWebSocketHandler(), "/websocket/server")
.addInterceptors(getInterceptor()).setAllowedOrigins("*");
registry.addHandler(getSpringWebSocketHandler(), "/sockjs/server").setAllowedOrigins("*")
.addInterceptors(getInterceptor()).withSockJS();
}
@Bean
public SpringWebSocketHandler getSpringWebSocketHandler() {
return new SpringWebSocketHandler();
}
@Bean
public SpringWebSocketHandlerInterceptor getInterceptor() {
return new SpringWebSocketHandlerInterceptor();
}
}
3、处理类（实现了WebSocketHandler接口）
package com.boot.river.websocket;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
public class SpringWebSocketHandler extends TextWebSocketHandler {
/**
* 存储用户id和其对应的session
*/
private static final Map<String, WebSocketSession> users = new HashMap<>();
/**
* 用户名key值
*/
private static final String USER_ID = "WEBSOCKET_USERID";
/**
* 连接建立后触发
*/
@Override
public void afterConnectionEstablished(WebSocketSession session) {
System.out.println("成功建立websocket连接!");
String userId = (String) session.getAttributes().get(USER_ID);//取出在拦截器中存储的username
users.put(userId, session);
System.out.println("当前线上用户数量:" + users.size());
}
/**
* 关闭连接时触发
*/
@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) {
String userId = (String) session.getAttributes().get(USER_ID);
System.out.println("用户" + userId + "已退出！");
users.remove(userId);
System.out.println("剩余在线用户" + users.size());
}
/**
* 接收消息
*/
@Override
protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
super.handleTextMessage(session, message);
System.out.println("收到消息：" + message);
if (message.getPayload().contains("在吗")) {
session.sendMessage(new TextMessage("对方不在线！"));
}
}
public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
if (session.isOpen()) {
session.close();
}
System.out.println("传输出现异常，关闭websocket连接... ");
String userId = (String) session.getAttributes().get(USER_ID);
users.remove(userId);
}
public boolean supportsPartialMessages() {
return false;
}
/**
* 给某个用户发送消息
*/
public void sendMessageToUser(String userId, TextMessage message) {
for (String id : users.keySet()) {
if (id.equals(userId)) {
try {
if (users.get(id).isOpen()) {
users.get(id).sendMessage(message);
}
} catch (IOException e) {
e.printStackTrace();
}
break;
}
}
}
/**
* 给所有在线用户发送消息
*/
public void sendMessageToUsers(TextMessage message) {
for (String userId : users.keySet()) {
try {
if (users.get(userId).isOpen()) {
users.get(userId).sendMessage(message);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
4、拦截器（实现HandshakeInterceptor接口）
package com.boot.river.websocket;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.http.server.ServletServerHttpRequest;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.support.HttpSessionHandshakeInterceptor;
import javax.servlet.http.HttpSession;
import java.util.Map;
public class SpringWebSocketHandlerInterceptor extends HttpSessionHandshakeInterceptor {
@Override
public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,