🐛 外网预签名固定 MinIO region，避免 GetBucketLocation 解析到 HTML

Co-authored-by: Cursor <cursoragent@cursor.com>

blade-service/blade-file/src/main/java/org/springblade/file/service/impl/MinioFileServiceImpl.java

@@ -65,6 +65,8 @@ import java.util.UUID;
 public class MinioFileServiceImpl extends AbstractFileService {
 
 	private static final long PART_SIZE = 10 * 1024 * 1024L;
+	/** MinIO 默认 region；固定后预签名无需再请求外网域名做 GetBucketLocation */
+	private static final String DEFAULT_REGION = "us-east-1";
 
 	private final FileStorageProperties.StoreProperties properties;
 	private final MinioClient minioClient;
@@ -82,6 +84,7 @@ public class MinioFileServiceImpl extends AbstractFileService {
 				.method(Method.PUT)
 				.bucket(properties.getBucketName())
 				.object(partObjectKey(objectKey, uploadId, partNumber))
+				.region(DEFAULT_REGION)
 				.expiry(Math.toIntExact(resolveExpires(expires)))
 				.build());
 			return applyTransformPathPrefix(presignedUrl);
@@ -186,6 +189,7 @@ public class MinioFileServiceImpl extends AbstractFileService {
 				.method(Method.GET)
 				.bucket(properties.getBucketName())
 				.object(resolveObjectKey(objectKey))
+				.region(DEFAULT_REGION)
 				.expiry(Math.toIntExact(resolveExpires(expires)))
 				.build());
 			return applyTransformPathPrefix(presignedUrl);
@@ -212,7 +216,10 @@ public class MinioFileServiceImpl extends AbstractFileService {
 
 	/**
 	 * 浏览器侧预签名优先使用外网地址，避免 HTTPS 页面访问 HTTP MinIO 被 Mixed Content 拦截。
+	 * <p>
 	 * MinIO SDK 不允许 endpoint 带 path，因此外网地址中的 /oss 等前缀在签名后单独拼回。
+	 * 外网域名通常是业务网关而非直连 MinIO，必须固定 region，否则 SDK 会请求 GetBucketLocation
+	 * 并拿到 HTML 页面导致 XmlParserException。
 	 */
 	private MinioClient resolvePresignClient() {
 		String transformEndpoint = properties.getTransformEndpoint();
@@ -228,6 +235,7 @@ public class MinioFileServiceImpl extends AbstractFileService {
 				transformPresignClient = MinioClient.builder()
 					.endpoint(resolveTransformOrigin(transformEndpoint))
 					.credentials(properties.getAccessKeyId(), properties.getAccessKeySecret())
+					.region(DEFAULT_REGION)
 					.build();
 			}
 			return transformPresignClient;