:Sample code for uploading data streams in parts by using OSS SDK for Java

Notes

• In this topic, the public endpoint for the China (Hangzhou) region is used. If you want to access OSS from other Alibaba Cloud services in the same region as OSS, we recommend that you use an internal endpoint. For more information about the mappings between regions and endpoints supported by OSS, see Regions and endpoints.

• In this topic, access credentials are obtained from environment variables. For information about how to configure access credentials, see Configure access credentials.

• In this topic, an OSSClient instance is created by using a public OSS endpoint. If you want to create an OSSClient instance by using a custom domain name or Security Token Service (STS), see Configure a client.

• To complete the entire multipart upload process, including InitiateMultipartUpload, UploadPart, and CompleteMultipartUpload, you must have the oss:PutObject permission. For more information about how to grant the permission, see Common examples of RAM policies.

Sample code

The following sample code performs a multipart upload of data streams:

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.CredentialsProviderFactory;
import com.aliyun.oss.common.auth.EnvironmentVariableCredentialsProvider;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.internal.Mimetypes;
import com.aliyun.oss.model.*;

public class MultipartUploadforStream {
    public static void main(String[] args) throws Exception {
        // In this example, the endpoint for the China (Hangzhou) region is used.
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";

        // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();

        // Specify the name of the bucket. Example: examplebucket.
        String bucketName = "examplebucket";

        // Specify the full path of the object. Example: exampledir/exampleobject.txt. Do not include the bucket name in the full path.
        String objectName = "exampledir/exampleobject.txt";

        // Specify the path of the local file that you want to upload.
        String filePath = "/Users/localFilePath/example.txt";

        // Specify the region where the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou.
        String region = "cn-hangzhou";

        // Create an OSSClient instance.
        // When the OSSClient instance is no longer USED, call the shutdown method to release resources.
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        try {
            // Create an InitiateMultipartUploadRequest object.
            InitiateMultipartUploadRequest request = new InitiateMultipartUploadRequest(bucketName, objectName);

            ObjectMetadata metadata = new ObjectMetadata();
            if (metadata.getContentType() == null) {
                metadata.setContentType(Mimetypes.getInstance().getMimetype(new File(filePath), objectName));
            }
            System.out.println("Content-Type: " + metadata.getContentType());
            request.setObjectMetadata(metadata);

            // Initiate the multipart upload task and obtain the upload ID in the response.
            InitiateMultipartUploadResult upresult = ossClient.initiateMultipartUpload(request);
            String uploadId = upresult.getUploadId();

            // partETags is a list of PartETags.
            List<PartETag> partETags = new ArrayList<>();

            // Calculate the number of parts.
            File sampleFile = new File(filePath);
            long fileLength = sampleFile.length();
            final long partSize = 5 * 1024 * 1024L; // Set the part size to 5 MB.

            // Upload all parts.
            try (FileInputStream instream = new FileInputStream(sampleFile)) {
                byte[] buffer = new byte[8192]; // Set the buffer.
                long remaining = fileLength;
                int partNumber = 1;

                while (remaining > 0) {
                    ByteArrayOutputStream baos = new ByteArrayOutputStream();
                    long bytesToRead = Math.min(partSize, remaining);

                    int bytesRead;
                    long totalRead = 0;
                    while (totalRead < bytesToRead && (bytesRead = instream.read(buffer)) > 0) {
                        baos.write(buffer, 0, bytesRead);
                        totalRead += bytesRead;
                    }

                    // Construct the part stream.
                    InputStream partStream = new ByteArrayInputStream(baos.toByteArray());

                    UploadPartRequest uploadPartRequest = new UploadPartRequest();
                    uploadPartRequest.setBucketName(bucketName);
                    uploadPartRequest.setKey(objectName);
                    uploadPartRequest.setUploadId(uploadId);
                    uploadPartRequest.setInputStream(partStream);
                    uploadPartRequest.setPartSize(totalRead);
                    uploadPartRequest.setPartNumber(partNumber++);

                    UploadPartResult uploadPartResult = ossClient.uploadPart(uploadPartRequest);
                    partETags.add(uploadPartResult.getPartETag());

                    remaining -= totalRead;
                }
            }

            // Create a CompleteMultipartUploadRequest object.
            CompleteMultipartUploadRequest completeMultipartUploadRequest =
                    new CompleteMultipartUploadRequest(bucketName, objectName, uploadId, partETags);

            // Complete the multipart upload task.
            CompleteMultipartUploadResult completeMultipartUploadResult = ossClient.completeMultipartUpload(completeMultipartUploadRequest);
            System.out.println("Upload successful, ETag: " + completeMultipartUploadResult.getETag());
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught a ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            // Shut down the OSSClient.
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

References

For more information about multipart upload in OSS, see Multipart upload.