use MD5 for ETag to be consistent with Amazon S3

other/java/s3copy/copier/src/main/java/com/seaweedfs/s3/PutObject.java

@@ -12,13 +12,21 @@ import com.amazonaws.services.s3.AmazonS3;
 import com.amazonaws.services.s3.AmazonS3ClientBuilder;
 import com.amazonaws.services.s3.model.ObjectMetadata;
 import com.amazonaws.services.s3.model.PutObjectRequest;
+import com.amazonaws.services.s3.model.S3Object;
+import com.amazonaws.util.IOUtils;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 
 import java.io.File;
+import java.io.IOException;
 
 /**
  * Hello world!
  */
 public class PutObject {
+
+    private static Log log = LogFactory.getLog(PutObject.class);
+
     public static void main(String[] args) {
 
         AWSCredentials credentials = new BasicAWSCredentials("ANY-ACCESSKEYID", "ANY-SECRETACCESSKEY");
@@ -39,10 +47,11 @@ public class PutObject {
         String fileObjKeyName = "fileObject2";
         String fileName = args[0];
 
+        String stringContent = "Uploaded String Object v3";
         try {
 
             // Upload a text string as a new object.
-            s3Client.putObject(bucketName, stringObjKeyName, "Uploaded String Object v3");
+            s3Client.putObject(bucketName, stringObjKeyName, stringContent);
 
             // Upload a file as a new object with ContentType and title specified.
             PutObjectRequest request = new PutObjectRequest(bucketName, fileObjKeyName, new File(fileName));
@@ -51,6 +60,23 @@ public class PutObject {
             metadata.addUserMetadata("x-amz-meta-title", "someTitle");
             request.setMetadata(metadata);
             s3Client.putObject(request);
+
+            S3Object written = s3Client.getObject(bucketName, stringObjKeyName);
+
+
+            try {
+                String expected = IOUtils.toString(written.getObjectContent());
+
+                if (!stringContent.equals(expected)){
+                    System.out.println("Failed to put and get back the content!");
+                }
+
+            } catch (IOException e) {
+                throw new SdkClientException("Error streaming content from S3 during download");
+            } finally {
+                IOUtils.closeQuietly(written, log);
+            }
+
         } catch (AmazonServiceException e) {
             // The call was transmitted successfully, but Amazon S3 couldn't process
             // it, so it returned an error response.