<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>4.2.0</version>
</dependency>
<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp-sse</artifactId>
    <version>4.2.0</version>
</dependency>

@GetMapping(value = "/test1", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
    public SseEmitter SseTest1() {
        SseEmitter sseEmitter = new SseEmitter();
        String prompt = "";
        String url = "";
        FormBody formBody = new FormBody.Builder().add("prompt", prompt).build();
        Request request = new Request.Builder().url(url).post(formBody).build();
        // 使用EventSourceListener處理來自服務(wù)器的SSE事件
        EventSourceListener listener = new EventSourceListener() {
            @Override
            public void onOpen(@NotNull EventSource eventSource, @NotNull Response response) {
                log.info("Connection opened.");
            }
            @Override
            public void onClosed(@NotNull EventSource eventSource) {
                log.info("Connection closed.");
                sseEmitter.complete();
            }
            @Override
            public void onEvent(@NotNull EventSource eventSource, @Nullable String id, @Nullable String type, @NotNull String data) {
                try {
                    JSONObject jsonObject = JSONUtil.parseObj(data);
                    String event = jsonObject.getStr("event");
                    if ("message".equals(event)) {
                        sseEmitter.send(jsonObject.getStr("answer"));
                    }
                } catch (Exception e) {
                    log.error("推送數(shù)據(jù)失敗", e);
                }
            }
            @Override
            public void onFailure(@NotNull EventSource eventSource, @Nullable Throwable t, @Nullable Response response) {
                log.error("Connection failed.", t);
                sseEmitter.completeWithError(t);
            }
        };
        OkHttpClient client = new OkHttpClient.Builder().connectTimeout(10, TimeUnit.SECONDS).writeTimeout(50, TimeUnit.SECONDS).readTimeout(10, TimeUnit.MINUTES).build();
        EventSource.Factory factory = EventSources.createFactory(client);
        factory.newEventSource(request, listener);
        return sseEmitter;
    }

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">

    <servlet>
        <servlet-name>MyServlet</servlet-name>
        <servlet-class>com.example.MyServlet</servlet-class>
        <async-supported>true</async-supported>
    </servlet>

    <servlet-mapping>
        <servlet-name>MyServlet</servlet-name>
        <url-pattern>/myServlet</url-pattern>
    </servlet-mapping>

</web-app>

@GetMapping("/test3")
    public void SseTest3(HttpServletRequest req, HttpServletResponse resp) {
        resp.setContentType("text/event-stream");
        resp.setCharacterEncoding("UTF-8");
        resp.setHeader("Cache-Control", "no-cache");
        resp.setHeader("Connection", "keep-alive");

        try {
            //
            AsyncContext asyncContext = req.startAsync(req, resp);
            asyncContext.setTimeout(10 * 60 * 1000);
            PrintWriter writer = asyncContext.getResponse().getWriter();

            String prompt = "";
            String url = "";
            FormBody formBody = new FormBody.Builder().add("prompt", prompt).build();
            Request request = new Request.Builder().url(url).post(formBody).build();
            // 使用EventSourceListener處理來自服務(wù)器的SSE事件
            EventSourceListener listener = new EventSourceListener() {
                @Override
                public void onOpen(@NotNull EventSource eventSource, @NotNull Response response) {
                    log.info("Connection opened.");
                }

                @Override
                public void onClosed(@NotNull EventSource eventSource) {
                    log.info("Connection closed.");
                    writer.write("data: __stop__\n\n");
                    writer.flush();
                    asyncContext.complete();
                }

                @Override
                public void onEvent(@NotNull EventSource eventSource, @Nullable String id, @Nullable String type, @NotNull String data) {
                    try {
                        JSONObject jsonObject = JSONUtil.parseObj(data);
                        String event = jsonObject.getStr("event");
                        if ("message".equals(event)) {
                            String answer = jsonObject.getStr("answer");
                            log.info("message: {}", answer);
                            writer.write("data: " + answer + "\n\n");
                            writer.flush();
                        }
                    } catch (Exception e) {
                        log.error("推送數(shù)據(jù)失敗", e);
                    }
                }

                @Override
                public void onFailure(@NotNull EventSource eventSource, @Nullable Throwable t, @Nullable Response response) {
                    log.error("Connection failed.", t);
                    asyncContext.complete();
                }
            };
            OkHttpClient client = new OkHttpClient.Builder().connectTimeout(10, TimeUnit.SECONDS).writeTimeout(50, TimeUnit.SECONDS).readTimeout(10, TimeUnit.MINUTES).build();
            EventSource.Factory factory = EventSources.createFactory(client);
            factory.newEventSource(request, listener);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {

        }
    }

// 以data: 開頭  /n/n結(jié)束
"data: xxxxx /n/n"

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>SSE Example</title>
</head>
<body>
    <div id="events"></div>
    <script>
        const source = new EventSource('/sse');

        source.onmessage = function(event) {
            const data = JSON.parse(event.data);
            // 約定一個結(jié)束標(biāo)識
            if(data == '__stop__') {
            	source.close()
            	return
            }
            document.getElementById('events').innerHTML += `<p>${data.message}</p>`;
        };

        source.onerror = function(error) {
            console.error('Error occurred:', error);
            source.close();
        };
    </script>
</body>
</html>

npm install --save @microsoft/fetch-event-source

// 導(dǎo)入依賴
import { fetchEventSource } from '@microsoft/fetch-event-source';
 
send() {
	const vm = this;
	const ctrlAbout = new AbortController();
	const { signal } = ctrlAbout;
	fetchEventSource(Url, {
	  method: 'POST',
	  headers: {
	    "Content-Type": 'application/json',
	    "Accept": 'text/event-stream'
	  },
	  body: JSON.stringify(data),
	  signal: ctrl.signal, // AbortSignal
	  onmessage(event) {
	     console.info(event.data);
	     // 在這里操作流式數(shù)據(jù)
	     const message = JSON.parse(event.data)
	     vm.content += message.data
	  },
	  onclose(e) {
	     // 關(guān)閉流
	     // 中斷流式返回
	     ctrl.abort()
	  }
	  onerror(error) {
	    // 返回流報錯
		console.info(error);
		// 中斷流式返回
		ctrl.abort()
		throw err // 直接拋出錯誤，避免反復(fù)調(diào)用
	  }
	})
}

@GetMapping("/test2")
    public void SseTest2() {
        String urlAddr = "";
        BufferedReader reader = null;
        try {
            URL url = new URL(urlAddr);
            // 建立鏈接
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Accept", "text/event-stream");
            connection.setRequestProperty("Content-type", "application/json; charset=UTF-8");
            connection.setRequestProperty("Cache-Control", "no-cache");
            connection.setRequestProperty("Connection", "keep-alive");
            // 允許輸入和輸出
            connection.setDoInput(true);
            connection.setDoOutput(true);
            // 設(shè)置超時為0，表示無限制
            connection.setConnectTimeout(0);
            connection.setReadTimeout(0);
            // 傳參
            String params = "prompt=哈哈哈哈";
            // 寫入POST數(shù)據(jù)
            DataOutputStream out = new DataOutputStream(connection.getOutputStream());
            out.write(params.getBytes(StandardCharsets.UTF_8));
            out.flush();
            out.close();

            // 讀取SSE事件
            reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), StandardCharsets.UTF_8));
            StringBuilder eventBuilder = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                System.out.println(line);
            }
            reader.close();
            // 斷開鏈接
            connection.disconnect();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            IoUtil.close(reader);
        }
    }