Help Center/ Object Storage Service/ SDK Reference/ Java/ Buckets (SDK for Java)/ Checking Whether a Bucket Exists (SDK for Java)
Updated on 2024-06-18 GMT+08:00

Checking Whether a Bucket Exists (SDK for Java)

Function

This API checks whether a bucket exists. If an HTTP status code 200 is returned, the bucket exists. If 404 is returned, the bucket does not exist.

If you have any questions during development, post them on the Issues page of GitHub.

Restrictions

Method

obsClient.headBucket(String bucketName)

Request Parameters

Table 1 List of request parameters

Parameter

Type

Mandatory (Yes/No)

Description

bucketName

String

Yes

Explanation:

Bucket name.

Restrictions:

  • A bucket name must be unique across all accounts and regions.
  • A bucket name:
    • Must be 3 to 63 characters long and start with a digit or letter. Lowercase letters, digits, hyphens (-), and periods (.) are allowed.
    • Cannot be formatted as an IP address.
    • Cannot start or end with a hyphen (-) or period (.).
    • Cannot contain two consecutive periods (..), for example, my..bucket.
    • Cannot contain periods (.) and hyphens (-) adjacent to each other, for example, my-.bucket or my.-bucket.
  • If you repeatedly create buckets of the same name in the same region, no error will be reported and the bucket attributes comply with those set in the first creation request.

Default value:

None

Responses

Table 2 List of returned results

Type

Description

boolean

Explanation:

Whether the bucket exists

Value range:

true: The bucket exists.

false: The bucket does not exist.

Default value:

None

Code Examples

This example checks whether bucket examplebucket exists.

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import com.obs.services.ObsClient;
import com.obs.services.exception.ObsException;
public class HeadBucket001 {
    public static void main(String[] args) {
        // Obtain an AK/SK pair using environment variables or import the AK/SK pair in other ways. Using hard coding may result in leakage.
        // Obtain an AK/SK pair on the management console.
        String ak = System.getenv("ACCESS_KEY_ID");
        String sk = System.getenv("SECRET_ACCESS_KEY_ID");
        // (Optional) If you are using a temporary AK/SK pair and a security token to access OBS, you are advised not to use hard coding, which may result in information leakage.
        // Obtain an AK/SK pair and a security token using environment variables or import them in other ways.
        // String securityToken = System.getenv("SECURITY_TOKEN");
        // Enter the endpoint corresponding to the bucket. CN-Hong Kong is used here as an example. Replace it with the one in your actual situation.
        String endPoint = "https://obs.ap-southeast-1.myhuaweicloud.com";
        // Obtain an endpoint using environment variables or import it in other ways.
        //String endPoint = System.getenv("ENDPOINT");

        // Create an ObsClient instance.
        // Use the permanent AK/SK pair to initialize the client.
        ObsClient obsClient = new ObsClient(ak, sk,endPoint);
        // Use the temporary AK/SK pair and security token to initialize the client.
        // ObsClient obsClient = new ObsClient(ak, sk, securityToken, endPoint);

        try {
            // Example bucket name
            String exampleBucket = "examplebucket";
            // Check whether the bucket exists.
            boolean exists = obsClient.headBucket(exampleBucket);
            System.out.println("HeadBucket successfully");
            System.out.println(exists);
        } catch (ObsException e) {
            System.out.println("HeadBucket failed");
            // Request failed. Print the HTTP status code.
            System.out.println("HTTP Code:" + e.getResponseCode());
            // Request failed. Print the server-side error code.
            System.out.println("Error Code :" + e.getErrorCode());
            // Request failed. Print the error details.
            System.out.println("Error Message:" + e.getErrorMessage());
            // Request failed. Print the request ID.
            System.out.println("Request ID:" + e.getErrorRequestId());
            System.out.println("Host ID:" + e.getErrorHostId());
        } catch (Exception e) {
            System.out.println("HeadBucket failed");
            // Print other error information.
            e.printStackTrace();
        }
    }
}

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