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。

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

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

此操作能為您的私有憑證授權機構 (CA) 擷取憑證簽署要求 (CSR)。CSR 會在您呼叫 [CreateCertificateAuthority](https://docs.aws.amazon.com/privateca/latest/APIReference/API_CreateCertificateAuthority.html) 操作時建立。將 CSR 帶到您的內部部署 X.509 基礎設施，並使用您的根 CA 或次級 CA 簽署。然後呼叫 [ImportCertificateAuthorityCertificate](https://docs.aws.amazon.com/privateca/latest/APIReference/API_ImportCertificateAuthorityCertificate.html) 操作，將已簽署的憑證匯入回 ACM PCA。CSR 會以 PEM 格式傳回為 base64 編碼字串。

```
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.GetCertificateAuthorityCsrRequest;
import com.amazonaws.services.acmpca.model.GetCertificateAuthorityCsrResult;

import com.amazonaws.AmazonClientException;
import com.amazonaws.services.acmpca.model.ResourceNotFoundException;
import com.amazonaws.services.acmpca.model.InvalidArnException;
import com.amazonaws.services.acmpca.model.RequestInProgressException;
import com.amazonaws.services.acmpca.model.RequestFailedException;
import com.amazonaws.services.acmpca.model.AWSACMPCAException;

import com.amazonaws.waiters.Waiter;
import com.amazonaws.waiters.WaiterParameters;
import com.amazonaws.waiters.WaiterTimedOutException;
import com.amazonaws.waiters.WaiterUnrecoverableException;

public class GetCertificateAuthorityCsr {

   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 the request object and set the CA ARN.
      GetCertificateAuthorityCsrRequest req = new GetCertificateAuthorityCsrRequest();
      req.withCertificateAuthorityArn("arn:aws:acm-pca:us-east-1:111122223333:certificate-authority/11223344-1234-1122-2233-112233445566");

      // Create waiter to wait on successful creation of the CSR file.
      Waiter<GetCertificateAuthorityCsrRequest> waiter = client.waiters().certificateAuthorityCSRCreated();
      try {
         waiter.run(new WaiterParameters<>(req));
      } catch (WaiterUnrecoverableException e) {
          //Explicit short circuit when the recourse transitions into
          //an undesired state.
      } catch (WaiterTimedOutException e) {
          //Failed to transition into desired state even after polling.
      } catch (AWSACMPCAException e) {
          //Unexpected service exception.
      }

      // Retrieve the CSR.
      GetCertificateAuthorityCsrResult result = null;
      try {
         result = client.getCertificateAuthorityCsr(req);
      } catch (RequestInProgressException ex) {
         throw ex;
      } catch (ResourceNotFoundException ex) {
         throw ex;
      } catch (InvalidArnException ex) {
         throw ex;
      } catch (RequestFailedException ex) {
         throw ex;
      }

      // Retrieve and display the CSR;
      String Csr = result.getCsr();
      System.out.println(Csr);
   }
}
```

您指定的憑證授權單位 (CA) 的輸出應類似下列。憑證簽署要求 (CSR) 是以 base64 編碼 (PEM 格式)。儲存到本機檔案，並帶到您的內部部署 X.509 基礎設施，然後使用您的根 CA 或次級 CA 簽署。

```
-----BEGIN CERTIFICATE REQUEST----- base64-encoded request -----END CERTIFICATE REQUEST-----
```