fix(内存): 两处无界内存风险加固——brand-check 线程池改有界队列+CallerRuns（大批量检查不再无界堆积 OOM）；OSS readObjectBytes 加 20MB 读取上限防大对象误用 OOM

backend-java/src/main/java/com/nanri/aiimage/modules/brand/client/BrandCheckClient.java

@@ -44,8 +44,14 @@ public class BrandCheckClient {
         this.externalCallMetrics = externalCallMetrics;
     }
 
-    private final ExecutorService checkExecutor = Executors.newFixedThreadPool(
+    // 有界队列 + CallerRuns：大批量（几千品牌）检查时队列洪峰不无界堆内存，
-            BRAND_CHECK_CONCURRENCY, namedThreadFactory("brand-check"));
+    // 队列打满时提交线程自己执行一个检查任务，上游天然限速。
+    private final ExecutorService checkExecutor = new java.util.concurrent.ThreadPoolExecutor(
+            BRAND_CHECK_CONCURRENCY, BRAND_CHECK_CONCURRENCY,
+            60L, java.util.concurrent.TimeUnit.SECONDS,
+            new java.util.concurrent.LinkedBlockingQueue<>(1000),
+            namedThreadFactory("brand-check"),
+            new java.util.concurrent.ThreadPoolExecutor.CallerRunsPolicy());
 
     @PreDestroy
     void shutdownCheckExecutor() {

backend-java/src/main/java/com/nanri/aiimage/modules/file/service/oss/OssStorageService.java

@@ -41,6 +41,8 @@ public class OssStorageService {
     private static final String DIGITAL_HUMAN_PREFIX = "digital-human/versions/";
     private static final String SOFTWARE_VERSION_PREFIX = "nanri-image/versions/";
     private static final String LEGACY_MINIO_ENDPOINT = "http://47.110.241.161:9000";
+    /** readObjectBytes 兜底读取上限（20MB）：防止大对象一次性读入内存导致 OOM。 */
+    private static final long DEFAULT_READ_MAX_BYTES = 20L * 1024 * 1024;
 
     private final OssProperties ossProperties;
     private final MinioClient minioClient;
@@ -248,13 +250,32 @@ public class OssStorageService {
     }
 
     public byte[] readObjectBytes(String bucket, String objectKey) {
+        // 防御性上限：防止被误用到大对象时一次性读入内存导致 OOM（当前仅模板下载场景，模板为 xlsx KB 级）
+        return readObjectBytes(bucket, objectKey, DEFAULT_READ_MAX_BYTES);
+    }
+
+    public byte[] readObjectBytes(String bucket, String objectKey, long maxBytes) {
         String normalizedBucket = requireStorageName(bucket, "bucket");
         String normalizedObjectKey = requireStorageName(objectKey, "objectKey");
         try (var stream = buildClient().getObject(GetObjectArgs.builder()
                 .bucket(normalizedBucket)
                 .object(normalizedObjectKey)
                 .build())) {
-            return stream.readAllBytes();
+            byte[] buffer = new byte[1024 * 1024];
+            ByteArrayOutputStream out = new ByteArrayOutputStream();
+            long total = 0;
+            int read;
+            while ((read = stream.read(buffer)) != -1) {
+                total += read;
+                if (total > maxBytes) {
+                    throw new IllegalArgumentException("对象过大，超过读取上限 " + maxBytes + " 字节: "
+                            + normalizedBucket + "/" + normalizedObjectKey);
+                }
+                out.write(buffer, 0, read);
+            }
+            return out.toByteArray();
+        } catch (IllegalArgumentException ex) {
+            throw ex;
         } catch (Exception ex) {
             throw storageFailure("read", normalizedBucket + "/" + normalizedObjectKey, ex);
         }