1、pom文件
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency>
2、前端代码
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title> Springboot集成SSE </title>
</head>
<script>let source = null;const clientId = new Date().getTime();if (!!window.EventSource) {source = new EventSource('http://127.0.0.1:8080/sse/subscribe?id=' + clientId);//建立连接source.onopen = function (event) {setMessageInnerHTML("建立连接" + event);}//接收数据source.onmessage = function (event) {setMessageInnerHTML(event.data);}//错误监听source.onerror = function (event) {if (event.readyState === EventSource.CLOSED) {setMessageInnerHTML("连接关闭");} else {console.log(event);}}} else {setMessageInnerHTML("浏览器不支持SSE");}window.onbeforeunload = function () {close();};// 关闭function close() {source.close();const httpRequest = new XMLHttpRequest();httpRequest.open('GET', '/sse/over/?clientId=' + clientId, true);httpRequest.send();console.log("close");}// 显示消息function setMessageInnerHTML(innerHTML) {document.getElementById('text').innerHTML += innerHTML + '<br/>';}
</script>
<body>
<button onclick="close()">关闭连接</button>
<div id="text"></div>
</body>
</html>
3、后端代码
1、订阅
private static Map<String, SseEmitter> cache = new ConcurrentHashMap<>();@GetMapping(path = "subscribe", produces = {MediaType.TEXT_EVENT_STREAM_VALUE})public SseEmitter subscribe(@RequestParam(name = "id", required = false) String id) throws IOException {// 超时时间设置SseEmitter sseEmitter = new SseEmitter(0L);cache.put(id, sseEmitter);//结束连接sseEmitter.onCompletion(() -> {log.info("结束连接：{}", id);cache.remove(id);});//连接异常sseEmitter.onError(throwable -> {log.info("连接异常：{}", id);cache.remove(id);});//连接超时sseEmitter.onTimeout(() -> {log.info("连接超时：{}", id);cache.remove(id);});return sseEmitter;}
2、推送
@GetMapping(path = "push/{userId}")public String push(@PathVariable String userId,@RequestBody Map<String,Object> param) throws IOException {try {SseEmitter sseEmitter = cache.get(userId);if (sseEmitter != null) {sseEmitter.send(SseEmitter.event().name("msg").data("后端发送消息：" + param));}} catch (IOException e) {log.error("用户[{}]推送异常:{}", userId, e.getMessage());cache.remove(userId);}return "over";}
3、关闭
@GetMapping(path = "over")public String over(@RequestParam(name = "id", required = false) String id) {SseEmitter sseEmitter = cache.get(id);if (sseEmitter != null) {sseEmitter.complete();cache.remove(id);}return "over";}
)
)
WAL log 模块基本原理)
