在 AWS SDK 中，Retry 并非仅适用于元数据服务。Retry 可以用于所有 AWS 服务 API 请求中。以下是一个示例，显示如何使用 RetryHandler 来执行 Amazon DynamoDB 请求以及如何在请求失败时进行自定义 Retry：

import com.amazonaws.AmazonClientException;
import com.amazonaws.AmazonServiceException;
import com.amazonaws.handlers.RequestHandler2;
import com.amazonaws.retry.RetryUtils;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder;
import com.amazonaws.services.dynamodbv2.model.*;

import java.util.HashMap;
import java.util.Map;

public class DynamoDBRetry {

    public static void main(String[] args) {

        AmazonDynamoDB client = AmazonDynamoDBClientBuilder.standard()
                .withRegion("us-west-2")
                .build();

        client.getRequestHandlers().add(new RequestHandler2() {
            @Override
            public AmazonWebServiceRequest beforeMarshalling(AmazonWebServiceRequest request) {
                // Adjust request before marshalling
                return request;
            }

            @Override
            public void afterResponse(AmazonWebServiceRequest request, Object response, TimingInfo timingInfo, AmazonWebServiceResponse amazonWebServiceResponse) {
                // Adjust response after unmarshalling
            }

            @Override
            public void afterError(AmazonWebServiceRequest request, AmazonClientException e) {
                if (RetryUtils.isThrottlingException(e)) {
                    // Retry on throttling exception
                    return;
                }

                if (e instanceof AmazonServiceException) {
                    AmazonServiceException ase = (AmazonServiceException) e;
                    if (RetryUtils.isRetryableServiceException(ase)) {
                        // Throw back exception with delay for custom retry logic
                        throw ase;
                    }
                }

                // Do nothing for other exceptions (e.g. non-AWS or networking issues)
            }
        });

        Map item = new HashMap<>();
        item.put("id", new AttributeValue().withN("1"));
        item.put("name", new AttributeValue().withS("John Doe"));

        PutItemRequest putItemRequest = new PutItemRequest()
                .withTableName("my-table")
                .withItem(item);

        try {
            client.putItem(putItemRequest);
        } catch (AmazonServiceException e) {
            // Handle service exceptions
        } catch (AmazonClientException e) {
            // Handle client exceptions
        }
    }
}

在此示例中，我们通过向 AmazonDynamoDBClient 添加 RequestHandler2 的实例来实现自定义 Retry 逻辑。此处理程序