如何通过JavaSDK列举Bucket下的文件 - 对象存储 OSS

本文介绍如何在开启版本控制状态下列举存储空间下（Bucket）的所有文件（Object）、指定个数的文件、指定前缀的文件等。

注意事项

本文以华东1（杭州）外网Endpoint为例。如果您希望通过与OSS同地域的其他阿里云产品访问OSS，请使用内网Endpoint。关于OSS支持的Region与Endpoint的对应关系，请参见OSS访问域名、数据中心、开放端口。
本文以从环境变量读取访问凭证为例。如何配置访问凭证，请参见Java配置访问凭证。
本文以OSS域名新建OSSClient为例。如果您希望通过自定义域名、STS等方式新建OSSClient，请参见新建OSSClient。
要列举文件，您必须有oss:ListObjectVersions权限。具体操作，请参见为RAM用户授权自定义的权限策略。

列举Bucket中所有Object的信息

以下代码用于列举指定Bucket中包括删除标记（Delete Marker）在内的所有Object的版本信息。

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;

public class Demo {
    public static void main(String[] args) throws Exception {
        // Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 填写Bucket名称，例如examplebucket。
        String bucketName = "examplebucket";
        // 填写Bucket所在地域。以华东1（杭州）为例，Region填写为cn-hangzhou。
        String region = "cn-hangzhou";

        // 创建OSSClient实例。
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);        
        OSS ossClient = OSSClientBuilder.create()
        .endpoint(endpoint)
        .credentialsProvider(credentialsProvider)
        .clientConfiguration(clientBuilderConfiguration)
        .region(region)               
        .build();

        try {
            // 列举包括删除标记在内的所有Object的版本信息。
            String nextKeyMarker = null;
            String nextVersionMarker = null;
            VersionListing versionListing = null;
            do {
                ListVersionsRequest listVersionsRequest = new ListVersionsRequest()
                        .withBucketName(bucketName)
                        .withKeyMarker(nextKeyMarker)
                        .withVersionIdMarker(nextVersionMarker);

                versionListing = ossClient.listVersions(listVersionsRequest);
                for (OSSVersionSummary ossVersion : versionListing.getVersionSummaries()) {
                    System.out.println("key name: " + ossVersion.getKey());
                    System.out.println("versionid: " + ossVersion.getVersionId());
                    System.out.println("Is latest: " + ossVersion.isLatest());
                    System.out.println("Is delete marker: " + ossVersion.isDeleteMarker());
                }

                nextKeyMarker = versionListing.getNextKeyMarker();
                nextVersionMarker = versionListing.getNextVersionIdMarker();
            } while (versionListing.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();
            }
        }
    }
}

列举指定前缀Object的版本信息

以下代码用于列举指定前缀Object的版本信息。

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.internal.OSSConstants;
import com.aliyun.oss.model.*;

public class Demo {
    public static void main(String[] args) throws Exception {
        // Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 填写Bucket名称，例如examplebucket。
        String bucketName = "examplebucket";

        // 创建OSSClient实例。
        OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);

        try {
            // 指定列举以"test-"为前缀的Object的版本信息。
            String prefix = "test-";
            String nextKeyMarker = null;
            String nextVersionMarker = null;
            VersionListing versionListing = null;
            do {
                ListVersionsRequest listVersionsRequest = new ListVersionsRequest()
                        .withBucketName(bucketName)
                        .withKeyMarker(nextKeyMarker)
                        .withVersionIdMarker(nextVersionMarker)
                        .withEncodingType(OSSConstants.URL_ENCODING)
                        .withPrefix(prefix);

                versionListing = ossClient.listVersions(listVersionsRequest);
                // 查看Object的版本信息。
                for (OSSVersionSummary ossVersion : versionListing.getVersionSummaries()) {
                    System.out.println("key name: " + ossVersion.getKey());
                    System.out.println("versionid: " + ossVersion.getVersionId());
                    System.out.println("Is latest: " + ossVersion.isLatest());
                    System.out.println("Is delete marker: " + ossVersion.isDeleteMarker());
                }

                nextKeyMarker = versionListing.getNextKeyMarker();
                nextVersionMarker = versionListing.getNextVersionIdMarker();
            } while (versionListing.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();
            }
        }
    }
}

列举指定个数Object的版本信息

以下代码用于列举指定个数Object的版本信息。

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;

public class Demo {
    public static void main(String[] args) throws Exception {
        // Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 填写Bucket名称，例如examplebucket。
        String bucketName = "examplebucket";

        // 创建OSSClient实例。
        OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);

        try {
            // 指定最多返回200个结果。
            ListVersionsRequest listVersionsRequest = new ListVersionsRequest()
                    .withBucketName(bucketName)
                    .withMaxResults(200);

            VersionListing versionListing = ossClient.listVersions(listVersionsRequest);
            for (OSSVersionSummary ossVersion : versionListing.getVersionSummaries()) {
                System.out.println("key name: " + ossVersion.getKey());
                // 在未开启版本控制的情况下，VersionId为none。
                System.out.println("versionid: " + ossVersion.getVersionId());
                System.out.println("Is latest: " + ossVersion.isLatest());
                System.out.println("Is delete marker: " + ossVersion.isDeleteMarker());
            }
        } 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();
            }
        }
    }
}

分页列举所有Object的版本信息

以下代码用于分页列举所有Object的版本信息。

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;

public class Demo {
    public static void main(String[] args) throws Exception {
        // Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 填写Bucket名称，例如examplebucket。
        String bucketName = "examplebucket";
        // 设置每页列举200个文件。
        int maxKeys = 200;

        // 创建OSSClient实例。
        OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);

        try {
            // 分页列举所有Object的版本信息。
            String nextKeyMarker = null;
            String nextVersionMarker = null;
            VersionListing versionListing = null;
            do {
                ListVersionsRequest listVersionsRequest = new ListVersionsRequest()
                        .withBucketName(bucketName)
                        .withKeyMarker(nextKeyMarker)
                        .withMaxResults(maxKeys)
                        .withVersionIdMarker(nextVersionMarker);

                versionListing = ossClient.listVersions(listVersionsRequest);
                for (OSSVersionSummary ossVersion : versionListing.getVersionSummaries()) {
                    System.out.println("key name: " + ossVersion.getKey());
                    System.out.println("versionid: " + ossVersion.getVersionId());
                    System.out.println("Is latest: " + ossVersion.isLatest());
                    System.out.println("Is delete marker: " + ossVersion.isDeleteMarker());
                }

                nextKeyMarker = versionListing.getNextKeyMarker();
                nextVersionMarker = versionListing.getNextVersionIdMarker();
            } while (versionListing.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();
            }
        }
    }
}

列举名称中包含特殊字符的Object

如果文件名称含有以下特殊字符，需要进行编码传输。OSS目前仅支持URL编码。

单引号（' '）
双引号（" "）
and符号（&）
尖括号（< >）
顿号（、）
中文

以下代码用于列举名称中包含特殊字符的Object。

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.internal.OSSConstants;
import com.aliyun.oss.model.*;

public class Demo {
    public static void main(String[] args) throws Exception {
        // Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 填写Bucket名称，例如examplebucket。
        String bucketName = "examplebucket";

        // 创建OSSClient实例。
        OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);

        try {
            // 指定返回结果以URL编码进行传输。
            String nextKeyMarker = null;
            String nextVersionMarker = null;
            VersionListing versionListing = null;
            do {
                ListVersionsRequest listVersionsRequest = new ListVersionsRequest()
                        .withBucketName(bucketName)
                        .withKeyMarker(nextKeyMarker)
                        .withVersionIdMarker(nextVersionMarker)
                        .withEncodingType(OSSConstants.URL_ENCODING);

                versionListing = ossClient.listVersions(listVersionsRequest);
                // 查看Object的版本信息。
                for (OSSVersionSummary ossVersion : versionListing.getVersionSummaries()) {
                    System.out.println("key name: " + ossVersion.getKey());
                    System.out.println("versionid: " + ossVersion.getVersionId());
                    System.out.println("Is latest: " + ossVersion.isLatest());
                    System.out.println("Is delete marker: " + ossVersion.isDeleteMarker());
                }

                nextKeyMarker = versionListing.getNextKeyMarker();
                nextVersionMarker = versionListing.getNextVersionIdMarker();
            } while (versionListing.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();
            }
        }
    }
}

文件夹功能

OSS没有文件夹的概念，所有元素都是以文件来存储。创建文件夹本质上来说是创建了一个大小为0并以正斜线（/）结尾的文件。这个文件可以被上传和下载，控制台会对以正斜线（/）结尾的文件以文件夹的方式展示。

通过delimiter和prefix两个参数可以模拟文件夹功能：

如果设置prefix为某个文件夹名称，则会列举以此prefix开头的文件，即该文件夹下所有的文件和子文件夹（目录）均显示为Object。
如果在设置了prefix的情况下，将delimiter设置为正斜线（/），则只列举该文件夹下的文件和子文件夹（目录），该文件夹下的子文件夹（目录）显示为CommonPrefixes，子文件夹下的文件和文件夹不显示。

假设存储空间中包含文件oss.jpg、fun/test.jpg、fun/movie/001.avi和fun/movie/007.avi，以正斜线（/）作为文件夹的分隔符。以下示例说明了如何通过模拟文件夹的方式列举文件。

列举根目录下的Object的版本信息

以下代码用于列举根目录下的Object的版本信息。

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.internal.OSSConstants;
import com.aliyun.oss.model.*;

public class Demo {
    public static void main(String[] args) throws Exception {
        // Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 填写Bucket名称，例如examplebucket。
        String bucketName = "examplebucket";

        // 创建OSSClient实例。
        OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);

        try {
            // 指定delimiter参数为正斜线（/），将会列举根目录下的Object的版本信息以及文件夹名称。
            String delimiter = "/";
            String nextKeyMarker = null;
            String nextVersionMarker = null;
            VersionListing versionListing = null;
            do {
                ListVersionsRequest listVersionsRequest = new ListVersionsRequest()
                        .withBucketName(bucketName)
                        .withKeyMarker(nextKeyMarker)
                        .withVersionIdMarker(nextVersionMarker)
                        .withEncodingType(OSSConstants.URL_ENCODING)
                        .withDelimiter(delimiter);

                versionListing = ossClient.listVersions(listVersionsRequest);
                // 查看Object的版本信息。
                for (OSSVersionSummary ossVersion : versionListing.getVersionSummaries()) {
                    System.out.println("key name: " + ossVersion.getKey());
                    System.out.println("versionid: " + ossVersion.getVersionId());
                    System.out.println("Is latest: " + ossVersion.isLatest());
                    System.out.println("Is delete marker: " + ossVersion.isDeleteMarker());
                }
                // 查看根目录下以正斜线（/）结尾的文件夹名称。
                for (String commonPrefix : versionListing.getCommonPrefixes()) {
                    System.out.println("commonPrefix: " + commonPrefix);
                }

                nextKeyMarker = versionListing.getNextKeyMarker();
                nextVersionMarker = versionListing.getNextVersionIdMarker();
            } while (versionListing.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();
            }
        }
    }
}

返回结果

key name: oss.jpg
versionid: CAEQEhiBgMCw8Y7FqBciIGIzMDE3MTEzOWRiMDRmZmFhMmRlMjljZWI0MWU4****
Is latest: true
Is delete marker: false

commonPrefix: fun/

以下代码用于列举指定目录下的文件和子目录。

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.internal.OSSConstants;
import com.aliyun.oss.model.*;

public class Demo {
    public static void main(String[] args) throws Exception {
        // Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 填写Bucket名称，例如examplebucket。
        String bucketName = "examplebucket";

        // 创建OSSClient实例。
        OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);

        try {
            // 设置prefix参数来获取fun目录下的所有文件与文件夹，同时设置delimiter参数为正斜线（/）作为文件夹的分隔符。
            String prefix = "fun/";  
            String delimiter = "/";
            String nextKeyMarker = null;
            String nextVersionMarker = null;
            VersionListing versionListing = null;
            do {
                ListVersionsRequest listVersionsRequest = new ListVersionsRequest()
                        .withBucketName(bucketName)
                        .withKeyMarker(nextKeyMarker)
                        .withVersionIdMarker(nextVersionMarker)
                        .withEncodingType(OSSConstants.URL_ENCODING)
                        .withDelimiter(delimiter)
                        .withPrefix(prefix);

                versionListing = ossClient.listVersions(listVersionsRequest);
                // 查看Object的版本信息。
                for (OSSVersionSummary ossVersion : versionListing.getVersionSummaries()) {
                    System.out.println("key name: " + ossVersion.getKey());
                    System.out.println("versionid: " + ossVersion.getVersionId());
                    System.out.println("Is latest: " + ossVersion.isLatest());
                    System.out.println("Is delete marker: " + ossVersion.isDeleteMarker());
                }
                // 查看fun目录下的子目录名称。
                for (String commonPrefix : versionListing.getCommonPrefixes()) {
                    System.out.println("commonPrefix: " + commonPrefix);
                }

                nextKeyMarker = versionListing.getNextKeyMarker();
                nextVersionMarker = versionListing.getNextVersionIdMarker();
            } while (versionListing.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();
            }
        }
    }
}

返回结果：

key name: fun/test.jpg
versionid: CAEQEhiBgIC48Y7FqBciIDU4NjAzMjczMTY5NDRjYmVhNGY4NTM2YTdjY2Ji****
Is latest: true
Is delete marker: false

commonPrefix: fun/movie/