我java sts连接oss 出现了Error code: NoSuchBucket

public static OSSObject downLoadImage(String fileName, OSS ossClient) throws UnsupportedEncodingException { // url过期时间为一小时 ms Date expiration = new Date(new Date().getTime() + 3600 * 1000); GeneratePresignedUrlRequest request = new GeneratePresignedUrlRequest(bucketName, fileName, HttpMethod.GET); request.setExpiration(expiration);// 设置过期时间。 // ResponseHeaderOverrides header = new ResponseHeaderOverrides(); // header.setContentDisposition("attachment;filename="+new String("fileName".getBytes(), "ISO-8859-1")); // request.setResponseHeaders(header);

    // 生成签名URL（HTTP GET请求）。
    URL signedUrl = ossClient.generatePresignedUrl(request);
    log.info("url签名{}", signedUrl);
    OSSObject object = ossClient.getObject(signedUrl, new HashMap<>());
    return object;