要获取AWS S3对象的分块元数据，可以使用AWS SDK提供的getObjectMetadata方法。下面是一个Java代码示例：

import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.GetObjectMetadataRequest;
import com.amazonaws.services.s3.model.ObjectMetadata;

public class GetObjectMetadataExample {

    public static void main(String[] args) {
        String bucketName = "your-bucket-name";
        String objectKey = "your-object-key";

        try {
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                    .withCredentials(new ProfileCredentialsProvider())
                    .build();

            GetObjectMetadataRequest getObjectMetadataRequest = new GetObjectMetadataRequest(bucketName, objectKey);
            ObjectMetadata objectMetadata = s3Client.getObjectMetadata(getObjectMetadataRequest);

            System.out.println("ETag: " + objectMetadata.getETag());
            System.out.println("Content-Type: " + objectMetadata.getContentType());
            System.out.println("Content-Length: " + objectMetadata.getContentLength());

            // 其他分块元数据
            // System.out.println("x-amz-meta-custom-field: " + objectMetadata.getUserMetadata("custom-field"));

        } catch (AmazonServiceException e) {
            e.printStackTrace();
        } catch (SdkClientException e) {
            e.printStackTrace();
        }
    }
}

请确保将your-bucket-name和your-object-key替换为实际的存储桶名称和对象键。还要确保您的AWS凭据正确配置，并且您已经在代码中指定了正确的AWS区域。