fix: SSE 流式转发从 RestTemplate 改用 OkHttp，支持真正的逐行流式读取，解决缓冲导致的一下子全出来问题

server/pom.xml

@@ -104,6 +104,13 @@
             <scope>runtime</scope>
         </dependency>
 
+        <!-- OkHttp：用于 SSE 流式转发，替代 RestTemplate 的缓冲行为 -->
+        <dependency>
+            <groupId>com.squareup.okhttp3</groupId>
+            <artifactId>okhttp</artifactId>
+            <version>4.12.0</version>
+        </dependency>
+
         <!-- JSON -->
         <dependency>
             <groupId>com.alibaba.fastjson2</groupId>

server/src/main/java/com/emotion/service/impl/ShortNovelServiceImpl.java

@@ -8,30 +8,29 @@ import com.emotion.dto.request.ShortNovelStreamRequest;
 import com.emotion.exception.BusinessException;
 import com.emotion.service.ShortNovelService;
 import com.emotion.util.UserContextHolder;
+import okhttp3.MediaType;
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
+import okhttp3.RequestBody;
+import okhttp3.Response;
+import okhttp3.ResponseBody;
+import okio.BufferedSource;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.http.HttpEntity;
-import org.springframework.http.HttpHeaders;
-import org.springframework.http.HttpMethod;
-import org.springframework.http.MediaType;
-import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Service;
-import org.springframework.web.client.RestTemplate;
 import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
 
-import java.io.BufferedReader;
-import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
 
 /**
  * 短篇小说外部服务代理实现
- * 使用 RestTemplate 读取外部 SSE 流并通过 SseEmitter 转发给小程序前端
+ * 使用 OkHttp 逐行流式读取外部 SSE 响应，通过 SseEmitter 转发给小程序前端
+ * OkHttp 的 ResponseBody.source() 是真正的网络流式读取，不会缓冲整个响应体
  *
  * @author huazhongmin
  * @date 2026-07-19
@@ -48,7 +47,29 @@ public class ShortNovelServiceImpl implements ShortNovelService {
     @Autowired
     private EpicScriptDialogueServiceImpl epicScriptDialogueServiceImpl;
 
-    private final RestTemplate restTemplate = new RestTemplate();
+    /**
+     * OkHttp 客户端：连接/读取超时与 Spring 配置对齐，支持 SSE 长连接流式读取
+     * 延迟初始化，避免 @Autowired 注入前 config 还未填充
+     */
+    private volatile OkHttpClient okHttpClient;
+
+    private OkHttpClient getOkHttpClient() {
+        if (okHttpClient == null) {
+            synchronized (this) {
+                if (okHttpClient == null) {
+                    okHttpClient = new OkHttpClient.Builder()
+                            .connectTimeout(config.getConnectTimeout(), TimeUnit.MILLISECONDS)
+                            .readTimeout(config.getReadTimeout(), TimeUnit.MILLISECONDS)
+                            .writeTimeout(config.getConnectTimeout(), TimeUnit.MILLISECONDS)
+                            .build();
+                }
+            }
+        }
+        return okHttpClient;
+    }
+
+    private static final MediaType JSON_MEDIA_TYPE = MediaType.parse("application/json; charset=utf-8");
+    private static final MediaType SSE_ACCEPT_TYPE = MediaType.parse("text/event-stream");
 
     @Override
     public SseEmitter stream(ShortNovelStreamRequest request) {
@@ -83,7 +104,7 @@ public class ShortNovelServiceImpl implements ShortNovelService {
     }
 
     /**
-     * 通用 SSE 转发逻辑
+     * 通用 SSE 转发逻辑（OkHttp 流式读取）
      *
      * @param path            外部服务路径
      * @param body            请求体
@@ -94,26 +115,36 @@ public class ShortNovelServiceImpl implements ShortNovelService {
         SseEmitter emitter = new SseEmitter(config.getReadTimeout().longValue());
 
         EXECUTOR.execute(() -> {
-            HttpHeaders headers = new HttpHeaders();
-            headers.setContentType(MediaType.APPLICATION_JSON);
-            headers.set("X-API-Token", config.getApiToken());
-            headers.set("Accept", "text/event-stream");
-
             String url = config.getApiBaseUrl() + path;
 
             try {
-                ResponseEntity<org.springframework.core.io.Resource> response = restTemplate.exchange(
+                // 构建 OkHttp 请求
-                        url, HttpMethod.POST,
+                Request okhttpRequest = new Request.Builder()
-                        new HttpEntity<>(JSON.toJSONString(body), headers),
+                        .url(url)
-                        org.springframework.core.io.Resource.class);
+                        .post(RequestBody.create(JSON.toJSONString(body), JSON_MEDIA_TYPE))
+                        .addHeader("X-API-Token", config.getApiToken())
+                        .addHeader("Accept", "text/event-stream")
+                        .build();
 
-                InputStream inputStream = response.getBody().getInputStream();
+                // OkHttp 执行请求，ResponseBody.source() 是真正的网络流
-                BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8));
+                try (Response response = getOkHttpClient().newCall(okhttpRequest).execute()) {
+                    if (!response.isSuccessful()) {
+                        throw new BusinessException("上游服务返回错误: HTTP " + response.code());
+                    }
 
-                String line;
+                    ResponseBody responseBody = response.body();
+                    if (responseBody == null) {
+                        throw new BusinessException("上游服务返回空响应体");
+                    }
+
+                    // source() 返回的 BufferedSource 逐行从网络 socket 读取，不会缓冲整个响应
+                    BufferedSource source = responseBody.source();
                     StringBuilder dataBuffer = new StringBuilder();
 
-                while ((line = reader.readLine()) != null) {
+                    while (!source.exhausted()) {
+                        String line = source.readUtf8Line();
+                        if (line == null) break;
+
                         if (line.startsWith("data:")) {
                             dataBuffer.append(line.substring(5).trim());
                         } else if (line.isEmpty() && dataBuffer.length() > 0) {
@@ -127,9 +158,6 @@ public class ShortNovelServiceImpl implements ShortNovelService {
                             try {
                                 JSONObject event = JSON.parseObject(dataStr);
                                 String type = event.getString("type");
-                            // 排查用：打印每个收到的事件类型，确认上游真实的"完成"事件名
-                            log.info("[ShortNovel SSE] 收到事件: type={}, session_id={}, keys={}",
-                                    type, event.getString("session_id"), event.keySet());
 
                                 // 拦截 novel_done 事件，保存到数据库
                                 if ("novel_done".equals(type)) {
@@ -155,7 +183,7 @@ public class ShortNovelServiceImpl implements ShortNovelService {
                                     }
                                 }
 
-                            // 转发事件给前端
+                                // 逐事件转发给前端（OkHttp 每读到一个完整 SSE 事件就立即转发）
                                 emitter.send(SseEmitter.event().name(type).data(event.toJSONString()));
                             } catch (Exception parseEx) {
                                 log.warn("SSE 事件解析失败: {}", parseEx.getMessage());
@@ -164,6 +192,7 @@ public class ShortNovelServiceImpl implements ShortNovelService {
                     }
 
                     emitter.complete();
+                }
             } catch (Exception e) {
                 log.error("SSE 代理异常: {}", e.getMessage(), e);
                 try {