OSS提供标准、低频访问、归档三种存储类型，全面覆盖从热到冷的各种数据存储场景。本文主要介绍如何转换文件（Object）的存储类型。

有关标准存储、低频访问、归档存储三种存储类型的更多信息，请参见开发指南的存储类型介绍及存储类型转换。

以下提供了详细的示例代码用于Object存储类型的相互转换。
  • 以下代码用于将Object的存储类型从标准或低频访问转换为归档类型： 
    #include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* 初始化OSS账号信息 */
    std::string AccessKeyId = "yourAccessKeyId";
    std::string AccessKeySecret = "yourAccessKeySecret";
    std::string Endpoint = "yourEndpoint";
    std::string SourceBucketName = "yourSourceBucketName";
    std::string SourceObjectName = "yourSourceObjectName";


    /* 初始化网络等资源 */
    InitializeSdk();

    ClientConfiguration conf;
    OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf);

    /* 设置修改后的文件存储类型，例如将修改后的文件存储类型设置为归档 */
    ObjectMetaData objectMeta;
    objectMeta.addHeader("x-oss-storage-class", "Archive");
    CopyObjectRequest request(SourceBucketName, SourceBucketName,objectMeta);
    request.setCopySource(SourceBucketName, SourceObjectName);

    /* 修改为上述指定的文件存储类型 */
    auto outcome = client.CopyObject(request);

    if (!outcome.isSuccess()) {
        /* 异常处理 */
        std::cout << "CopyObject fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        ShutdownSdk();
        return -1;
    }

    /* 释放网络等资源 */
    ShutdownSdk();
    return 0;
}
  • 以下代码用于将Object的存储类型从归档转换为低频访问类型： 
    #include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* 初始化OSS账号信息 */
    std::string AccessKeyId = "yourAccessKeyId";
    std::string AccessKeySecret = "yourAccessKeySecret";
    std::string Endpoint = "yourEndpoint";
    std::string SourceBucketName = "yourSourceBucketName";
    std::string SourceObjectName = "yourSourceObjectName";

    /* 初始化网络等资源 */
    InitializeSdk();

    ClientConfiguration conf;
    OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf);

    /* 检查目标文件是否为归档类型。如果是，则需要先解冻才能更改存储类型 */
    auto restoreOutcome = client.RestoreObject(SourceBucketName, SourceObjectName);
    if (!restoreOutcome.isSuccess()) {
        /* 异常处理 */
        std::cout << "RestoreObject fail" <<
        ",code:" << restoreOutcome.error().Code() <<
        ",message:" << restoreOutcome.error().Message() <<
        ",requestId:" << restoreOutcome.error().RequestId() << std::endl;
        ShutdownSdk();
        return -1;
    }

    std::string onGoingRestore("ongoing-request=\"false\"");

    int maxWaitTimeInSeconds = 600;
    while (maxWaitTimeInSeconds > 0)
    {
        auto meta = client.HeadObject(SourceBucketName, SourceObjectName);

        std::string restoreStatus = meta.result().HttpMetaData()["x-oss-restore"];
        std::transform(restoreStatus.begin(), restoreStatus.end(), restoreStatus.begin(), ::tolower);
        if (!restoreStatus.empty() && 
        restoreStatus.compare(0, onGoingRestore.size(), onGoingRestore)==0) {
            std::cout << " success, restore status:" << restoreStatus << std::endl;
            /* 成功解冻归档文件*/
            break;
        }

        std::cout << " info, WaitTime:" << maxWaitTimeInSeconds
        << "; restore status:" << restoreStatus << std::endl;

        std::this_thread::sleep_for(std::chrono::seconds(10));
        maxWaitTimeInSeconds--;     
    }

    /* 设置修改后的文件存储类型，例如将修改后的文件存储类型设置为低频 */
    ObjectMetaData objectMeta;
    objectMeta.addHeader("x-oss-storage-class", "IA");
    CopyObjectRequest request(SourceBucketName, SourceBucketName,objectMeta);
    request.setCopySource(SourceBucketName, SourceObjectName);

    /* 修改为上述指定的文件存储类型 */
    auto outcome = client.CopyObject(request);

    if (!outcome.isSuccess()) {
        /* 异常处理 */
        std::cout << "CopyObject fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        ShutdownSdk();
        return -1;
    }

    /* 释放网络等资源 */
    ShutdownSdk();
    return 0;
}

各种存储类型的存储费用介绍，请参见计量项和计费项的存储费用一节。