• springboot使用SSE

    1、pom文件 

    1.  <dependency>
    2.       <groupId>org.springframework.bootgroupId>
    3.       <artifactId>spring-boot-starter-webartifactId>
    4.  dependency>

    2、前端代码

    1. html>
    2. <html lang="en">
    3. <head>
    4.     <meta charset="UTF-8">
    5.     <title> Springboot集成SSE title>
    6. head>
    7. <script>
    8.     let source = null;
    9.     const clientId = new Date().getTime();
    10.     if (!!window.EventSource) {
    11.  
    12.         source = new EventSource('http://127.0.0.1:8080/sse/subscribe?id=' + clientId);
    13.  
    14.     	//建立连接
    15.         source.onopen = function (event) {
    16.             setMessageInnerHTML("建立连接" + event);
    17.         }
    18.         //接收数据
    19.         source.onmessage = function (event) {
    20.             setMessageInnerHTML(event.data);
    21.         }
    22.         //错误监听
    23.         source.onerror = function (event) {
    24.             if (event.readyState === EventSource.CLOSED) {
    25.                 setMessageInnerHTML("连接关闭");
    26.             } else {
    27.                 console.log(event);
    28.             }
    29.         }
    30.     } else {
    31.         setMessageInnerHTML("浏览器不支持SSE");
    32.     }
    33.  
    34.     window.onbeforeunload = function () {
    35.         close();
    36.     };
    37.  
    38.     // 关闭
    39.     function close() {
    40.         source.close();
    41.         const httpRequest = new XMLHttpRequest();
    42.         httpRequest.open('GET', '/sse/over/?clientId=' + clientId, true);
    43.         httpRequest.send();
    44.         console.log("close");
    45.     }
    46.  
    47.     // 显示消息
    48.     function setMessageInnerHTML(innerHTML) {
    49.         document.getElementById('text').innerHTML += innerHTML + '
      '      ;
    50.     }
    51. script>
    52. <body>
    53. <button onclick="close()">关闭连接button>
    54. <div id="text">div>
    55. body>
    56. html>

    3、后端代码

    1、订阅
    1. private static Map cache = new ConcurrentHashMap<>();
    2. 	@GetMapping(path = "subscribe", produces = {MediaType.TEXT_EVENT_STREAM_VALUE})
    3. 	public SseEmitter subscribe(@RequestParam(name = "id", required = false) String id) throws IOException {
    4. 		// 超时时间设置
    5. 		SseEmitter sseEmitter = new SseEmitter(0L);
    6. 		
    7. 		cache.put(id, sseEmitter);
    8. 		//结束连接
    9. 		sseEmitter.onCompletion(() -> {
    10. 			log.info("结束连接：{}", id);
    11. 			cache.remove(id);
    12. 		});
    13. 		//连接异常
    14. 		sseEmitter.onError(throwable -> {
    15. 			log.info("连接异常：{}", id);
    16. 			cache.remove(id);
    17. 		});
    18. 		//连接超时
    19. 		sseEmitter.onTimeout(() -> {
    20. 			log.info("连接超时：{}", id);
    21. 			cache.remove(id);
    22. 		});
    23. 		return sseEmitter;
    24. 	}
    2、推送
    1. @GetMapping(path = "push/{userId}")
    2. 	public String push(@PathVariable String userId,@RequestBody Map param) throws IOException {
    3. 		try {
    4. 			SseEmitter sseEmitter = cache.get(userId);
    5. 			if (sseEmitter != null) {
    6. 				sseEmitter.send(SseEmitter.event().name("msg").data("后端发送消息：" + param));
    7. 			}
    8. 		} catch (IOException e) {
    9. 			log.error("用户[{}]推送异常:{}", userId, e.getMessage());
    10. 			cache.remove(userId);
    11. 		}
    12. 		return "over";
    13. 	}
    3、关闭
    1. @GetMapping(path = "over")
    2. 	public String over(@RequestParam(name = "id", required = false) String id) {
    3. 		SseEmitter sseEmitter = cache.get(id);
    4. 		if (sseEmitter != null) {
    5. 			sseEmitter.complete();
    6. 			cache.remove(id);
    7. 		}
    8. 		return "over";
    9. 	}

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  • 原文地址：https://blog.csdn.net/qq_38410795/article/details/132950545