When uploading void txt file has been getting "File upload error" #4

awsfs/src/main/java/io/jmix/awsfs/AwsFileStorage.java

@@ -23,6 +23,7 @@
 import io.jmix.core.TimeSource;
 import io.jmix.core.UuidProvider;
 import io.jmix.core.annotation.Internal;
+import io.jmix.core.common.util.Preconditions;
 import org.apache.commons.io.FilenameUtils;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.lang3.StringUtils;
@@ -51,6 +52,7 @@
 import software.amazon.awssdk.services.s3.model.GetObjectRequest;
 import software.amazon.awssdk.services.s3.model.ListObjectsV2Request;
 import software.amazon.awssdk.services.s3.model.ListObjectsV2Response;
+import software.amazon.awssdk.services.s3.model.PutObjectRequest;
 import software.amazon.awssdk.services.s3.model.S3Object;
 import software.amazon.awssdk.services.s3.model.UploadPartRequest;
 
@@ -140,6 +142,8 @@ protected AwsCredentialsProvider getAwsCredentialsProvider() {
 
     public void refreshS3Client() {
         refreshProperties();
+        Preconditions.checkNotEmptyString(region, "region must not be empty");
+        Preconditions.checkNotEmptyString(bucket, "bucket must not be empty");
         AwsCredentialsProvider awsCredentialsProvider = getAwsCredentialsProvider();
         if (Strings.isNullOrEmpty(endpointUrl)) {
             s3ClientReference.set(S3Client.builder()
@@ -193,6 +197,14 @@ public FileRef saveStream(String fileName, InputStream inputStream) {
             S3Client s3Client = s3ClientReference.get();
             int chunkSizeBytes = this.chunkSize * 1024;
 
+            if (data.length == 0) {
+                s3Client.putObject(PutObjectRequest.builder()
+                        .bucket(bucket)
+                        .key(fileKey)
+                        .build(), RequestBody.fromBytes(data));
+                return new FileRef(getStorageName(), fileKey, fileName);
+            }
+
             CreateMultipartUploadRequest createMultipartUploadRequest = CreateMultipartUploadRequest.builder()
                     .bucket(bucket)
                     .key(fileKey)