Spring Boot 开发私有即时通信系统（WebSocket）

<properties>
 <java.version>1.8</java.version>
 <thymeleaf.version>3.0.0.RELEASE</thymeleaf.version>
 <thymeleaf-layout-dialect.version>2.0.0</thymeleaf-layout-dialect.version>
 </properties>

 <dependencies>

 <!-- WebSocket依赖，移除Tomcat容器 -->
 <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-websocket</artifactId>
  <exclusions>
  <exclusion>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-tomcat</artifactId>
  </exclusion>
  </exclusions>
 </dependency>

 <!-- 使用Undertow容器 -->
 <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-undertow</artifactId>
 </dependency>

 <!-- Spring Security 框架 -->
 <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-security</artifactId>
 </dependency>

 <!-- MongoDB数据库 -->
 <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-mongodb</artifactId>
 </dependency>

 <!-- Thymeleaf 模版引擎 -->
 <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-thymeleaf</artifactId>
 </dependency>

 <dependency>
  <groupId>org.projectlombok</groupId>
  <artifactId>lombok</artifactId>
  <version>1.16.16</version>
 </dependency>

 <dependency>
  <groupId>com.alibaba</groupId>
  <artifactId>fastjson</artifactId>
  <version>1.2.30</version>
 </dependency>

 <!-- 静态资源 -->
 <dependency>
  <groupId>org.webjars</groupId>
  <artifactId>webjars-locator</artifactId>
 </dependency>
 <dependency>
  <groupId>org.webjars</groupId>
  <artifactId>sockjs-client</artifactId>
  <version>1.0.2</version>
 </dependency>
 <dependency>
  <groupId>org.webjars</groupId>
  <artifactId>stomp-websocket</artifactId>
  <version>2.3.3</version>
 </dependency>
 <dependency>
  <groupId>org.webjars</groupId>
  <artifactId>bootstrap</artifactId>
  <version>3.3.7</version>
 </dependency>
 <dependency>
  <groupId>org.webjars</groupId>
  <artifactId>jquery</artifactId>
  <version>3.1.0</version>
 </dependency>

 </dependencies>

server:
 port: 80

# 若使用MongoDB则配置如下参数
spring:
 data:
 mongodb:
  uri: mongodb://username:password@172.25.11.228:27017
  authentication-database: admin
  database: chat

@SpringBootApplication
@EnableWebSocket
public class Application {

 public static void main(String[] args) {
 SpringApplication.run(Application.class, args);
 }

}

@Configuration
@EnableWebSocketMessageBroker
@Log4j
public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {

 // 此处可注入自己写的Service

 @Override
 public void registerStompEndpoints(StompEndpointRegistry stompEndpointRegistry) {
 // 客户端与服务器端建立连接的点
 stompEndpointRegistry.addEndpoint("/any-socket").withSockJS();
 }

 @Override
 public void configureMessageBroker(MessageBrokerRegistry messageBrokerRegistry) {
 // 配置客户端发送信息的路径的前缀
 messageBrokerRegistry.setApplicationDestinationPrefixes("/app");
 messageBrokerRegistry.enableSimpleBroker("/topic");
 }

 @Override
 public void configureWebSocketTransport(final WebSocketTransportRegistration registration) {
 registration.addDecoratorFactory(new WebSocketHandlerDecoratorFactory() {
  @Override
  public WebSocketHandler decorate(final WebSocketHandler handler) {
  return new WebSocketHandlerDecorator(handler) {
   @Override
   public void afterConnectionEstablished(final WebSocketSession session) throws Exception {
   // 客户端与服务器端建立连接后，此处记录谁上线了
   String username = session.getPrincipal().getName();
   log.info("online: " + username);
   super.afterConnectionEstablished(session);
   }

   @Override
   public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
   // 客户端与服务器端断开连接后，此处记录谁下线了
   String username = session.getPrincipal().getName();
   log.info("offline: " + username);
   super.afterConnectionClosed(session, closeStatus);
   }
  };
  }
 });
 super.configureWebSocketTransport(registration);
 }
}

@Controller
@Log4j
public class ChatController {

 @Autowired
 private SimpMessagingTemplate template;

 // 注入其它Service

 // 群聊天
 @MessageMapping("/notice")
 public void notice(Principal principal, String message) { 
 // 参数说明 principal 当前登录的用户， message 客户端发送过来的内容
 // principal.getName() 可获得当前用户的username 

 // 发送消息给订阅 "/topic/notice" 且在线的用户
 template.convertAndSend("/topic/notice", message); 
 }

 // 点对点聊天
 @MessageMapping("/chat")
 public void chat(Principal principal, String message){
 // 参数说明 principal 当前登录的用户， message 客户端发送过来的内容（应该至少包含发送对象toUser和消息内容content）
 // principal.getName() 可获得当前用户的username

 // 发送消息给订阅 "/user/topic/chat" 且用户名为toUser的用户
 template.convertAndSendToUser(toUser, "/topic/chat", content);
 }

}

 var stompClient = null;

 function connect() {
  var socket = new SockJS('/any-socket');
  stompClient = Stomp.over(socket);
  stompClient.connect({}, function (frame) {
   // 订阅 /topic/notice 实现群聊
   stompClient.subscribe('/topic/notice', function (message) {
    showMessage(JSON.parse(message.body));
   });
   // 订阅 /user/topic/chat 实现点对点聊
   stompClient.subscribe('/user/topic/chat', function (message) {
    showMessage(JSON.parse(message.body));
   });
  });
 }

 function showMessage(message) {
  // 处理消息在页面的显示
 }

 $(function () {
  // 建立websocket连接
  connect();
  // 发送消息按钮事件
  $("#send").click(function () {
   if (target == "TO_ALL"){
    // 群发消息
    // 匹配后端ChatController中的 @MessageMapping("/notice")
    stompClient.send("/app/notice", {}, '消息内容');
   }else{
    // 点对点消息，消息中必须包含对方的username
    // 匹配后端ChatController中的 @MessageMapping("/chat")
    var content = "{'content':'消息内容','receiver':'anoy'}";
    stompClient.send("/app/chat", {}, content);
   }
  });
 });