Java管理软链接

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。

• 要创建软链接，您必须具有oss:PutObject权限；要获取软链接，您必须具有oss:GetObject权限。具体操作，请参见为RAM用户授权自定义的权限策略。

创建软链接

软链接本身也可以有多个版本，每个不同的版本可以指向不同的TargetObject，版本ID由OSS自动生成，在响应Header中返回x-oss-version-id。

以下代码用于创建软链接：

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";
        // 填写软链接名称。
        String symLink = "yourSymLink";
        // 填写Object的完整路径。Object完整路径中不能包含Bucket名称。
        String destinationObjectName = "exampledir/object";
        // 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 {
            // 创建上传文件元数据。
            ObjectMetadata metadata = new ObjectMetadata();
            metadata.setContentType("text/plain");
            // 设置自定义元数据property的值为property-value。
            metadata.addUserMetadata("property", "property-value");

            // 创建CreateSymlinkRequest。
            CreateSymlinkRequest createSymlinkRequest = new CreateSymlinkRequest(bucketName, symLink, destinationObjectName);

            // 设置元数据。
            createSymlinkRequest.setMetadata(metadata);
            // 填写Object的versionId。
            createSymlinkRequest.setVersionId("CAEQFhiCgID3rZDy3hgiIGQxOTIxOWU0M2NlYzQ2ODdhMTQwOGRlZGQxMzEx****");

            // 创建软链接。
            ossClient.createSymlink(createSymlinkRequest);
        } 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();
            }
        }
    }
}

获取软链接

以下代码用于获取软链接：

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";
        // 填写软链接名称。
        String symLink = "yourSymLink";
        // 填写软链接的versionId。
        String versionId  = "CAEQMxiBgICAof2D0BYiIDJhMGE3N2M1YTI1NDQzOGY5NTkyNTI3MGYyMzJm****";
        // 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 {            
            GenericRequest genericRequest = new GenericRequest(bucketName, symLink, versionId);
            OSSSymlink symbolicLink = ossClient.getSymlink(genericRequest);
            // 打印软链接名称。
            System.out.println(symbolicLink.getSymlink());
            // 打印软连接指向的文件名称。
            System.out.println(symbolicLink.getTarget());
            System.out.println(symbolicLink.getRequestId());
            // 打印软链接的versionId。
            System.out.println(symbolicLink.getMetadata().getVersionId());
        } 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();
            }
        }
    }
}

相关文档

• 关于创建软链接的API接口说明，请参见PutSymlink。

• 关于获取软链接的API接口说明，请参见GetSymlink。