如何在具有IAM角色的ec2实例上使用java访问dynamodb而无需访问凭据

import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.*;

public class DynamoDBExample {
    public static void main(String[] args) {
        // 指定要访问的地区和表名
        Region region = Region.AP_Guangzhou;
        String tableName = "your-table-name";

        // 创建DynamoDB客户端
        DynamoDbClient client = DynamoDbClient.builder()
                .region(region)
                .build();

        // 构造查询请求
        ScanRequest request = ScanRequest.builder()
                .tableName(tableName)
                .build();

        // 发送请求并处理响应
        ScanResponse response = client.scan(request);
        response.items().forEach(item -> {
            // 处理每个项目
            System.out.println(item);
        });

        // 关闭客户端
        client.close();
    }
}