spring-boot支持websocket

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

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@Configuration
@EnableWebSocket
public 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beforeHandshakeafterHandshake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。

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public class MessageWebSocketInterceptor implements HandshakeInterceptor {
@Override
public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object> 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

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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

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@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<Throwable> failure = new AtomicReference<>();
@LocalServerPort
private int port;
private SockJsClient sockJsClient;
@Before
public void setup() {
List<Transport> 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<Throwable> failure;
TestWebSocketHandler() {
this.failure = null;
}
;
TestWebSocketHandler(AtomicReference<Throwable> 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ws-guide。有问题还是直接看spring文档比较好。

一个java web程序员,希望自己两年之内能成为data scientist,正在找工作