spring-boot本身对websocket提供了很好的支持，可以直接原生支持sockjs和stomp协议。百度搜了一些中文文档，虽然也能实现websocket，但是并没有直接使用spring-boot直接支持的websocket的特性。

在实践中觉得stromp协议对于websocket开发的自由度影响比较大。这里给大家展示一种自由度比较大的方案。

主要就是三个组件，config，interceptor和handler

@Configuration@EnableWebSocketpublic class MessageWebSocketConfig implements WebSocketConfigurer {    @Override    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {        registry.addHandler(messageWebSocketHandler(), "/sockjs/message")                .addInterceptors(new MessageWebSocketInterceptor()).withSockJS();    }    @Bean    public MessageWebSocketHandler messageWebSocketHandler() {        return new MessageWebSocketHandler();    }}

config需要继承WebSocketConfigurer需要重写registerWebSocketHandlers方法，指明handler和interceptor。

interceptor顾名思义为拦截器我们可以在websocket建立之间和之后做一些事情。重载beforeHandshake和afterHandshake就OK。我在beforeHandshake这里还操作了attributes。被修改的attributes会被带到后面websocket的session之中。

public class MessageWebSocketInterceptor implements HandshakeInterceptor {    @Override    public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map
    
      attributes) throws Exception {        if (request instanceof ServletServerHttpRequest) {            ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) request;            String siteId = servletRequest.getServletRequest().getParameter("siteId");            String userId = servletRequest.getServletRequest().getParameter("userId");            if (siteId == null || userId == null) {                return false;            }            attributes.put("siteId", siteId);            attributes.put("userId", userId);        }        return true;    }    @Override    public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Exception exception) {    }}
    

handler里面就可以写websocket的逻辑啦

public class MessageWebSocketHandler implements WebSocketHandler {    @Override    public void afterConnectionEstablished(WebSocketSession session) {    }    @Override    public void handleMessage(WebSocketSession session, WebSocketMessage
     message) {    }    @Override    public void handleTransportError(WebSocketSession session, Throwable exception) {    }    @Override    public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) {    }    @Override    public boolean supportsPartialMessages() {        return false;    }}

spring-boot单元测试可以写websocket-client

@RunWith(SpringRunner.class)@SpringBootTest(classes = {Application.class}, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)public class WebsocketTest {    private final Logger logger = LoggerFactory.getLogger(WebsocketTest.class);    private final WebSocketHttpHeaders headers = new WebSocketHttpHeaders();    final CountDownLatch latch = new CountDownLatch(1);    final AtomicReference
    
      failure = new AtomicReference<>();    @LocalServerPort    private int port;    private SockJsClient sockJsClient;    @Before    public void setup() {        List
     
       transports = new ArrayList<>();        transports.add(new WebSocketTransport(new StandardWebSocketClient()));        transports.add(new RestTemplateXhrTransport());        this.sockJsClient = new SockJsClient(transports);    }    @Test    public void getGreeting() throws Exception {        this.sockJsClient.doHandshake(new TestWebSocketHandler(failure),                "ws://localhost:"+String.valueOf(port)+"/sockjs/message?siteId=webtrn&userId=lucy");        if (latch.await(60, TimeUnit.SECONDS)) {            if (failure.get() != null) {                throw new AssertionError("", failure.get());            }        }        else {            fail("Greeting not received");        }    }    private class TestWebSocketHandler implements WebSocketHandler {        private final AtomicReference
      
        failure;        TestWebSocketHandler() {            this.failure = null;        }        ;        TestWebSocketHandler(AtomicReference
       
         failure) {            this.failure = failure;        }        ;        @Override        public void afterConnectionEstablished(WebSocketSession session) throws Exception {            logger.info("client connection established");            session.sendMessage(new TextMessage("hello websocket server!"));        }        @Override        public void handleMessage(WebSocketSession session, WebSocketMessage
         message) throws Exception {            String payload = (String) message.getPayload();            logger.info("client handle message: " + payload);            if (payload.equals("hello websocket client! webtrn lucy")) {                latch.countDown();            }            if (payload.equals("web socket notify")) {                latch.countDown();            }        }        @Override        public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {            logger.info("client transport error");        }        @Override        public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {            logger.info("client connection closed");        }        @Override        public boolean supportsPartialMessages() {            return false;        }    }}
       
      
     
    

如果采用stomp协议的话可以参考spring-boot的一个。有问题还是直接看spring文档比较好。