调用AWS createPresignedPost方法上传文件时返回凭证错误

解决方法：需要检查使用的AWSCredentials是否正确，并且确保在创建AWS S3客户端时也传递了正确的AWSCredentialsProvider。

示例代码：

BasicAWSCredentials credentials = new BasicAWSCredentials("accessKeyId", "secretAccessKey");
AmazonS3 s3client = AmazonS3ClientBuilder.standard()
                  .withCredentials(new AWSStaticCredentialsProvider(credentials))
                  .withRegion(Regions.US_EAST_1)
                  .build();
          
GeneratePresignedUrlRequest request = new GeneratePresignedUrlRequest(bucketName, objectKey);
PresignedUrlUploadRequest uploadRequest = new PresignedUrlUploadRequest(request);
 
try {
     PresignedUrlUploadResult uploadResult = s3client.presign(uploadRequest);
     // 文件上传成功
} catch (AmazonS3Exception e) {
     // 处理异常
}