虽然这是一个老问题，并且反馈是在2015年提供的，但现在它要简单得多，因为S3 Web控制台启用了“获取大小”选项:

它提供了以下内容:

Aws s3 ls s3://bucket-name/folder-prefix-if-any——recursive | wc -l .使用实例

以下是如何使用java客户端。

<dependency>
    <groupId>com.amazonaws</groupId>
    <artifactId>aws-java-sdk-s3</artifactId>
    <version>1.11.519</version>
</dependency>

import com.amazonaws.ClientConfiguration;
import com.amazonaws.Protocol;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.ObjectListing;

public class AmazonS3Service {

    private static final String S3_ACCESS_KEY_ID = "ACCESS_KEY";
    private static final String S3_SECRET_KEY = "SECRET_KEY";
    private static final String S3_ENDPOINT = "S3_URL";

    private AmazonS3 amazonS3;

    public AmazonS3Service() {
        ClientConfiguration clientConfiguration = new ClientConfiguration();
        clientConfiguration.setProtocol(Protocol.HTTPS);
        clientConfiguration.setSignerOverride("S3SignerType");
        BasicAWSCredentials credentials = new BasicAWSCredentials(S3_ACCESS_KEY_ID, S3_SECRET_KEY);
        AWSStaticCredentialsProvider credentialsProvider = new AWSStaticCredentialsProvider(credentials);
        AmazonS3ClientBuilder.EndpointConfiguration endpointConfiguration = new AmazonS3ClientBuilder.EndpointConfiguration(S3_ENDPOINT, null);
        amazonS3 = AmazonS3ClientBuilder.standard().withCredentials(credentialsProvider).withClientConfiguration(clientConfiguration)
                .withPathStyleAccessEnabled(true).withEndpointConfiguration(endpointConfiguration).build();
    }

    public int countObjects(String bucketName) {
        int count = 0;
        ObjectListing objectListing = amazonS3.listObjects(bucketName);
        int currentBatchCount = objectListing.getObjectSummaries().size();
        while (currentBatchCount != 0) {
            count += currentBatchCount;
            objectListing = amazonS3.listNextBatchOfObjects(objectListing);
            currentBatchCount = objectListing.getObjectSummaries().size();
        }
        return count;
    }
}

下面是上面嵌入的python脚本的boto3版本。

import sys
import boto3

s3 = boto3.resource("s3")
s3bucket = s3.Bucket(sys.argv[1])
size = 0
totalCount = 0

for key in s3bucket.objects.all():
    totalCount += 1
    size += key.size

print("total size:")
print("%.3f GB" % (size * 1.0 / 1024 / 1024 / 1024))
print("total count:")
print(totalCount)

截至2020年11月18日，现在有一种更简单的方法来获取这些信息，而无需对API请求征税:

AWS S3存储镜头

默认的，内置的，免费的仪表板允许您查看所有桶的计数，或在“buckets”选项卡下的单个桶。有许多下拉列表可以过滤和排序几乎任何你想要寻找的合理指标。

如果使用s3cmd命令行工具，可以获得特定桶的递归列表，并将其输出到文本文件。

s3cmd ls -r s3://logs.mybucket/subfolder/ > listing.txt

然后在linux中，您可以对文件运行wc -l来计算行数(每个对象1行)。

wc -l listing.txt