Download Object
The SDKs present in the section will allow you to download a particular object, or version of the object. The Bucket reference used in the below code snippet is the component instance.
The first step of the download operation is a GET operation that retrieves the required object from the bucket.
To be able to download an object, the requester must have READ access permissions. However, owners of the bucket do have the option to grant READ access permissions to users, allowing them to download the object without using the required response headers.
If Versioning is enabled for your bucket, you need to pass the versionId to download the particular version of the object. If no versionId is passed, then by default, the latest version of the object will be downloaded.
If Versioning was enabled for a bucket, then disabled. By default, the principal first object will be downloaded. To ensure you download the latest version of this object, you need to pass the versionId param with the value “topVersion”.
Ensure the following packages are imported
import java.nio.file.Path;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;
import java.io.*;
InputStream dataStream = bucket.getObject("sam/out/sample.txt");
// download the object to your local machine
Path path = Path.of("file_path"); // specify a path to store the downloaded object
Files.copy(dataStream, path, StandardCopyOption.REPLACE_EXISTING);
Download a Portion of the Object
The following SDK implements the setRange() method. This method allows you to download a specific range of bytes of an object.
Ensure the following packages are imported
import com.zc.component.stratus.beans.ZCGetObjectOptions;
import java.nio.file.Path;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;
import java.io.*;
// add download options
ZCGetObjectOptions options = ZCGetObjectOptions.getInstance();
options.setVersionId("3yt5ehjbjghds3i28");
options.setRange("20-200"); // start and end range of the object in bytes
InputStream dataStream = bucket.getObject("sam/out/sample.txt", options);
// download the object to your local machine
Path path = Path.of("file_path"); // specify a path to store the downloaded object
Files.copy(dataStream, path, StandardCopyOption.REPLACE_EXISTING);
Download an Object Using Transfer Manager
In this section, we are going to go over SDK methods that will allow you to successfully download large objects from Stratus to your local system using Transfer Manager technique. Transfer Manager is an operation where the large object is split into multiple byte ranges using the start and end bytes range of the object. Each of the object’s parts is then returned as a stream, and they are downloaded to your local system.
Create Transfer Manager Instance
Ensure the following packages are imported
import com.zc.component.stratus.transfer.ZCTransferManager;
ZCTransferManager transferManager= ZCTransferManager.getInstance(bucket);
Download Object as Iterable Part Streams
Ensure the following packages are imported
import java.nio.file.StandardOpenOption;
import java.nio.file.Files;
import java.util.Iterator;
import java.nio.file.Path;
import java.io.*;
Iterable <InputStream> Iterable = transferManager.getIterableObject("sam/out/sample.txt", 100 L);
Path path = Path.of("file_path");
Iterator <InputStream> res = Iterable.iterator();
while (res.hasNext()) {
InputStream data = res.next(); // get each part of the object as stream
Files.copy(data, path, StandardCopyOption.REPLACE_EXISTING); // write the stream to local file path
}
Generate Object Parts for Download
In this SDK method we will download a portion of the object that falls under the required start and end range of bytes.
Parameters Used
- PartSize: It is the size of each part in Mb
- key: Will hold the name of the object
Ensure the following packages are imported
import java.nio.file.StandardOpenOption;
import java.nio.file.Files;
import com.zc.component.stratus.beans.ZCStratusGetObject;
import java.nio.file.Path;
import java.io.*;
Path path = Path.of("file_path");
// get the list of part functions
List<ZCStratusGetObject> parts = transferManager.generatePartDownloaders("sam/out/sample.txt", 100L);
// create a file to store the downloaded stream.
Files.createFile(path);
int partNumber = 1;
// trigger the each function to download the object parts
for (ZCStratusGetObject part : parts) {
// get object part as stream
InputStream inputStream = part.getPart();
System.out.println("Part "+ partNumber++ + " Downloaded");
// write the stream data to local machine
Files.write(path, inputStream.readAllBytes(), StandardOpenOption.APPEND);
}
Generate Presigned URL to Download an Object
Presigned URLs are secure URLs that authenticated users can share to their non-authenticated users. This URL will provide non-authenticated users with temporary authorization to access objects. The Bucket reference used in the below code snippet is the component instance.
Parameters Used
Parameter Name | Data Type | Definition |
---|---|---|
key | String | A Mandatory parameter. Will hold the complete name of the object along with it's path. |
URL_ACTION | Enum | A Mandatory parameter. This is the parameter that will allow you to generate a presigned URL for download action.
|
expiry | String | This is an Optional parameter. The URL validity time in seconds.
|
activeFrom | String | This is an Optional parameter. This param will contain the time after which the URL is valid. Maximum value is 7 days. URLs are made active as soon as they are generated by default. |
Ensure the following packages are imported
import com.zc.component.stratus.enums.URL_ACTION;
import org.json.simple.JSONObject;
JSONObject res = bucket.generatePreSignedUrl("sam/out/sample.txt",URL_ACTION.GET);
System.out.println(res.get("signature"));
Generate Presigned URL With Expiry and Active Time
Ensure the following packages are imported
import com.zc.component.stratus.enums.URL_ACTION;
import org.json.simple.JSONObject;
JSONObject res = bucket.generatePreSignedUrl("object_name",URL_ACTION.GET, "expiry_in","active_from");
System.out.println(res.get("signature"));
Example Response for Generating a Presigned URL for Download
{
signature: 'https://sadi-development.zoho stratus.com/_signed/text.txt?organizationId=96862383&stsCredential=96858154-96862383&stsDate=1747896279887&stsExpiresAfter=300&stsSignedHeaders=host&stsSignature=3YBUX1HFSxNQzQJjFrln82AyJsEEuC5T9dsZwWxGyEE'
}
Example Snippet Illustrating Usage of Presigned URL to Upload an Object
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.ResponseBody;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class Download {
public static void main(String[] args) throws IOException {
// Create an OkHttpClient instance to handle the HTTP request
OkHttpClient client = new OkHttpClient();
// Build the GET request with the pre-signed URL
Request request1 = new Request.Builder()
.url("https://sadi-development.zohostratus.com/_signed/sam.txt?organizationId=96862383&stsCredential=96858154-96862383&stsDate=1747905744487&stsExpiresAfter=300&stsSignedHeaders=host&stsSignature=pCjV9xckDOqBCueE_gBeMbp12StddTghBK_8HUwU5k0") // Replace with your actual URL
.build();
// Execute the request and handle the response
try (Response response1 = client.newCall(request1).execute()) {
// Check if the response was successful
if (!response1.isSuccessful()) {
throw new IOException("Unexpected code " + response1);
}
// Get the response body as an InputStream
ResponseBody body = response1.body();
if (body != null) {
// Create a stream to write the file to disk
try (InputStream in = body.byteStream();
OutputStream out = new FileOutputStream("file_path")) { // Replace file_path with the actual path
// Read the response data in chunks and write to the file
byte[] buffer = new byte[8192];
int len;
while ((len = in.read(buffer)) != -1) {
out.write(buffer, 0, len);
}
// Print confirmation after successful download
System.out.println("Download complete.");
}
}
} catch (IOException e) {
// Print stack trace if an error occurs during the download
e.printStackTrace();
}
}
}
Last Updated 2025-07-02 15:43:56 +0530 IST
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