本文介绍如何使用分片上传。
上传步骤
分片上传（Multipart Upload）分为以下三个步骤：
初始化一个分片上传事件。
调用initiateMultipartUpload方法返回OSS创建的全局唯一的uploadId。
上传分片。
调用uploadPart方法上传分片数据。
完成分片上传。
所有分片上传完成后，调用completeMultipartUpload方法将所有分片合并成完整的文件。
以下通过一个完整的示例对分片上传的流程进行逐步解析：
public void testMutipartUploadObject() {
try {
long contentLength = file.length();
// 设置分片大小为5MB
long partSize = 5 * 1024 * 1024;
// 初始化分片上传
InitiateMultipartUploadResult initiateResult = s3
.initiateMultipartUpload(new InitiateMultipartUploadRequest(BUCKET_NAME, KEY)
.withCannedACL(CannedAccessControlList.Private)
.withStorageClass(StorageClass.Standard));
long filePosition = 0;
List<PartETag> partETags = new ArrayList<>();
for (int i = 1; filePosition < contentLength; i++) {
partSize = Math.min(partSize, (contentLength - filePosition));
// 上传分片
UploadPartRequest uploadRequest = new UploadPartRequest()
.withBucketName(BUCKET_NAME)
.withKey(KEY)
.withUploadId(initiateResult.getUploadId())
.withPartNumber(i)
.withFileOffset(filePosition)
.withFile(file)
.withPartSize(partSize);
UploadPartResult uploadResult = s3.uploadPart(uploadRequest);
partETags.add(uploadResult.getPartETag());
filePosition += partSize;
}
// 完成分片上传
CompleteMultipartUploadRequest compRequest = new CompleteMultipartUploadRequest(BUCKET_NAME, KEY,
initiateResult.getUploadId(), partETags);
s3.completeMultipartUpload(compRequest);
} catch (AmazonS3Exception e) {
System.out.print("Append object faild, err :" + e);
}
} |
取消分片上传事件
您可以调用abortMultipartUpload方法来取消分片上传事件。当一个分片上传事件被取消后，无法再使用这个uploadId做任何操作，已经上传的分片数据会被删除。
以下代码用于取消分片上传事件：
public void testAbortMutiPartUpload() {
try {
ListMultipartUploadsRequest allMultipartUploadsRequest = new ListMultipartUploadsRequest(bucketName);
MultipartUploadListing multipartUploadListing = s3.listMultipartUploads(allMultipartUploadsRequest);
List<MultipartUpload> uploads = multipartUploadListing.getMultipartUploads();
System.out.println("Before deletions, " + uploads.size() + " multipart uploads in progress.");
// Abort each upload.
for (MultipartUpload u : uploads) {
System.out.println("Upload in progress: Key = \"" + u.getKey() + "\", id = " + u.getUploadId());
s3.abortMultipartUpload(new AbortMultipartUploadRequest(bucketName, u.getKey(), u.getUploadId()));
System.out.println("Upload deleted: Key = \"" + u.getKey() + "\", id = " + u.getUploadId());
}
// Verify that all in-progress multipart uploads have been aborted.
multipartUploadListing = s3.listMultipartUploads(allMultipartUploadsRequest);
uploads = multipartUploadListing.getMultipartUploads();
System.out.println("After aborting uploads, " + uploads.size() + " multipart uploads in progress.");
} catch (AmazonServiceException e) {
System.err.println(e.getErrorMessage());
}
} |
列举正在上传的分片
以下代码用于简单列举正在上传的分片：
public void testListMutiPartUpload() {
try {
ListMultipartUploadsRequest allMultipartUploadsRequest = new ListMultipartUploadsRequest(bucketName);
MultipartUploadListing multipartUploadListing = s3.listMultipartUploads(allMultipartUploadsRequest);
List<MultipartUpload> uploads = multipartUploadListing.getMultipartUploads();
System.out.println(uploads.size() + " multipart upload(s) in progress.");
for (MultipartUpload u : uploads) {
System.out.println("Upload in progress: Key = \"" + u.getKey() + "\", id = " + u.getUploadId());
}
} catch (AmazonServiceException e) {
System.err.println(e.getErrorMessage());
}
} |
