在使用应用程序访问Key Vault获取密钥信息时，现后遇见了多种认证错误。使用的代码为：
String keyVaultUrl = "https://test-xxx.vault.azure.cn/"
String keyName = "keyvault-xxx";
KeyClient keyClient = new KeyClientBuilder()
.vaultUrl(keyVaultUrl)
.credential(new DefaultAzureCredentialBuilder()
.tenantId("3c858e6a-xxxx-xxxx-xxxx-xxxxxxxxxxxx")
.managedIdentityClientId("3df5246c-xxxx-xxxx-xxxx-xxxxxxxxxxxx")
.build())
.buildClient();
KeyVaultKey key = keyClient.getKey(keyName);
遇见的错误一：
Error Details: AADSTS90002: Tenant '3c858e6a-xxxx-xxxx-xxxx-xxxxxxxxxxxx' not found. This may happen if there are no active subscriptions for the tenant. Check to make sure you have the correct tenant ID. Check with your subscription administrator
错误分析：
根据Key Vaule的URL判断，服务位于中国区的Azure中，由于中国区的Azure和Globa Azure是两个独立的云环境，所以在使用SDK登录中国区Azure环境时，需要指定Authority Host。所以需要在代码中加入 " .authorityHost(AzureAuthorityHosts.AZURE_CHINA) “。
修改后的代码为：
String keyVaultUrl = "https://test-xxx.vault.azure.cn/"
String keyName = "keyvault-xxx";
KeyClient keyClient = new KeyClientBuilder()
.vaultUrl(keyVaultUrl)
.credential(new DefaultAzureCredentialBuilder()
.tenantId("3c858e6a-xxxx-xxxx-xxxx-xxxxxxxxxxxx")
.authorityHost(AzureAuthorityHosts.AZURE_CHINA)
.managedIdentityClientId("3df5246c-xxxx-xxxx-xxxx-xxxxxxxxxxxx")
.build())
.buildClient();
KeyVaultKey key = keyClient.getKey(keyName);
遇见的错误二：
IntelliJ Authentication not available. Please log in with Azure Tools for IntelliJ plugin in the IDE
Status code 403, "{"error":{"code":"Forbidden","message":"The policy requires the caller 'appid=60015a25-xxxx-xxxx-xxxx-xxxxxxxxxxxx;oid=dc107e73-xxxx-xxxx-xxxx-xxxxxxxxxxxx;iss=https://sts.chinacloudapi.cn/3c858e6a-xxxx-xxxx-xxxx-xxxxxxxxxxxx/' to use on-behalf-of (OBO) flow. For more information on OBO, please see https://go.microsoft.com/fwlink/?linkid=2152310","innererror":{"code":"ForbiddenByPolicy"}}}"
错误分析：
因为访问Azure Key Vault需要添加访问策略，需要为当前使用的 Client ID (3df5246c-xxxx-xxxx-xxxx-xxxxxxxxxxxx)配置 访问策略[Access Policy]
遇见的错误三：
认证主题不是自定义的AAD注册应用，而是服务主体（Service Principal) ， 所以需要使用 ClientSecretCredential 对象进行认证，而不是默认的 DefaultAzureCredentialBuilder 。
使用ClientSecretCredential 认证的参考代码为：
/**
* Authenticate with client secret.
*/
ClientSecretCredential clientSecretCredential = new ClientSecretCredentialBuilder()
.clientId("<your client ID>")
.clientSecret("<your client secret>")
.tenantId("<your tenant ID>")
.authorityHost(AzureAuthorityHosts.AZURE_CHINA)
.build();
// Azure SDK client builders accept the credential as a parameter.
SecretClient client = new SecretClientBuilder()
.vaultUrl("https://<your Key Vault name>.vault.azure.net")
.credential(clientSecretCredential)
.buildClient();
参考资料：
Client secret credential：https://docs.microsoft.com/en-us/azure/developer/java/sdk/identity-service-principal-auth#client-secret-credential
对 Azure 托管的 Java 应用程序进行身份验证: https://docs.microsoft.com/zh-cn/azure/developer/java/sdk/identity-azure-hosted-auth
当在复杂的环境中面临问题，格物之道需：浊而静之徐清，安以动之徐生。 云中，恰是如此!
