本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。

# DescribeCertificateAuthority
<a name="JavaApi-DescribeCertificateAuthority"></a>

以下 Java 範例說明如何使用 [DescribeCertificateAuthority](https://docs.aws.amazon.com/privateca/latest/APIReference/API_DescribeCertificateAuthority.html) 操作。

此操作可列出私有憑證授權機構 (CA) 的相關資訊。您必須指定私有 CA 的 ARN (Amazon Resource Name)。輸出包含 CA 的狀態。此可為下列任何一項：
+ `CREATING` – AWS 私有 CA 正在建立您的私有憑證授權機構。
+ `PENDING_CERTIFICATE` – 憑證正在等待。您必須使用現場部署的根 CA 或次級 CA 來簽署私有 CA CSR，然後將其匯入 PCA。
+ `ACTIVE` – 您的私有 CA 已啟用。
+ `DISABLED` – 您的私有 CA 已停用。
+ `EXPIRED` – 您的私有 CA 憑證已過期。
+ `FAILED` – 無法建立您的私有 CA。
+ `DELETED` – 您的私有 CA 位於還原期間內，之後會永久刪除。

```
package com.amazonaws.samples;

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.client.builder.AwsClientBuilder;
import com.amazonaws.client.builder.AwsClientBuilder.EndpointConfiguration;
import com.amazonaws.auth.AWSStaticCredentialsProvider;

import com.amazonaws.services.acmpca.AWSACMPCA;
import com.amazonaws.services.acmpca.AWSACMPCAClientBuilder;

import com.amazonaws.services.acmpca.model.CertificateAuthority;
import com.amazonaws.services.acmpca.model.DescribeCertificateAuthorityRequest;
import com.amazonaws.services.acmpca.model.DescribeCertificateAuthorityResult;

import com.amazonaws.AmazonClientException;
import com.amazonaws.services.acmpca.model.ResourceNotFoundException;
import com.amazonaws.services.acmpca.model.InvalidArnException;

public class DescribeCertificateAuthority {

   public static void main(String[] args) throws Exception {

      // Retrieve your credentials from the C:\Users\name\.aws\credentials file
      // in Windows or the .aws/credentials file in Linux.
      AWSCredentials credentials = null;
      try {
         credentials = new ProfileCredentialsProvider("default").getCredentials();
      } catch (Exception e) {
         throw new AmazonClientException("Cannot load your credentials from disk", e);
      }

      // Define the endpoint for your sample.
      String endpointRegion = "{{region}}";  // Substitute your region here, e.g. "us-west-2"
      String endpointProtocol = "https://acm-pca." + endpointRegion + ".amazonaws.com/";
      EndpointConfiguration endpoint =
            new AwsClientBuilder.EndpointConfiguration(endpointProtocol, endpointRegion);

      // Create a client that you can use to make requests.
      AWSACMPCA client = AWSACMPCAClientBuilder.standard()
         .withEndpointConfiguration(endpoint)
         .withCredentials(new AWSStaticCredentialsProvider(credentials))
         .build();

      // Create a request object
      DescribeCertificateAuthorityRequest req = new DescribeCertificateAuthorityRequest();

      // Set the certificate authority ARN.
      req.withCertificateAuthorityArn("arn:{{aws}}:acm-pca:{{us-east-1}}:{{111122223333}}:certificate-authority/{{11223344-1234-1122-2233-112233445566}}");

      // Create a result object.
      DescribeCertificateAuthorityResult result = null;
      try {
         result = client.describeCertificateAuthority(req);
      } catch (ResourceNotFoundException ex) {
         throw ex;
      } catch (InvalidArnException ex) {
         throw ex;
      }

      // Retrieve and display information about the CA.
      CertificateAuthority PCA = result.getCertificateAuthority();
      String strPCA = PCA.toString();
      System.out.println(strPCA);
   }
}
```