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Performing a Partial Download

If you have any questions during development, post them on the Issues page of GitHub. For details about parameters and usage of each API, see the API Reference

When only partial data of an object is required, you can download data falling within a specific range. If the specified range is 0 to 1000, data at the 0th to the 1000th bytes, 1001 bytes in total, will be returned. If the specified range is invalid, data of the whole object will be returned. Sample code is as follows:

String endPoint = "https://your-endpoint";
String ak = "*** Provide your Access Key ***";
String sk = "*** Provide your Secret Key ***";

// Create an instance of ObsClient.
final ObsClient obsClient = new ObsClient(ak, sk, endPoint);

GetObjectRequest request = new GetObjectRequest("bucketname", "objectname");
// Set the start position and end position for downloading.
request.setRangeStart(0l);
request.setRangeEnd(1000l);
ObsObject obsObject = obsClient.getObject(request);

// Obtain data.
byte[] buf = new byte[1024];
InputStream in = obsObject.getObjectContent();
for (int n = 0; n != -1; ) {
    n = in.read(buf, 0, buf.length);
}

in.close();
  • If the specified range is invalid (because the start or end position is set to a negative integer or the range is larger than the object length), data of the whole object will be returned.
  • This download method also can be used to concurrently download parts of a large object. For details about the sample code, see ConcurrentDownloadObjectSample.
Parent topic: Object Download