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# 描述集合
您可以使用 [DescribeCollection](https://docs.aws.amazon.com/rekognition/latest/APIReference/API_DescribeCollection.html) 操作获取有关集合的下列信息：
+ 在集合中索引的人脸数量。
+ 与集合一起使用的模型版本。有关更多信息，请参阅 [了解模型版本控制](face-detection-model.md)。
+ 集合的 Amazon 资源名称 (ARN)。
+ 集合的创建日期和时间。
**描述集合 (SDK)**
1. 如果您尚未执行以下操作，请：
1. 使用 `AmazonRekognitionFullAccess` 权限创建或更新用户。有关更多信息，请参阅 [步骤 1：设置 AWS 账户并创建用户](setting-up.md#setting-up-iam)。
1. 安装并配置 AWS CLI 和 AWS SDKs。有关更多信息，请参阅 [第 2 步：设置 AWS CLI 和 AWS SDKs](setup-awscli-sdk.md)。
1. 使用以下示例调用 `DescribeCollection` 操作。
------
#### [ Java ]
此示例描述集合。
将值 `collectionId` 更改为所需集合的 ID。
```
//Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
//PDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-rekognition-developer-guide/blob/master/LICENSE-SAMPLECODE.)
package com.amazonaws.samples;
import com.amazonaws.services.rekognition.AmazonRekognition;
import com.amazonaws.services.rekognition.AmazonRekognitionClientBuilder;
import com.amazonaws.services.rekognition.model.DescribeCollectionRequest;
import com.amazonaws.services.rekognition.model.DescribeCollectionResult;
public class DescribeCollection {
public static void main(String[] args) throws Exception {
String collectionId = "CollectionID";
AmazonRekognition rekognitionClient = AmazonRekognitionClientBuilder.defaultClient();
System.out.println("Describing collection: " +
collectionId );
DescribeCollectionRequest request = new DescribeCollectionRequest()
.withCollectionId(collectionId);
DescribeCollectionResult describeCollectionResult = rekognitionClient.describeCollection(request);
System.out.println("Collection Arn : " +
describeCollectionResult.getCollectionARN());
System.out.println("Face count : " +
describeCollectionResult.getFaceCount().toString());
System.out.println("Face model version : " +
describeCollectionResult.getFaceModelVersion());
System.out.println("Created : " +
describeCollectionResult.getCreationTimestamp().toString());
}
}
```
------
#### [ Java V2 ]
此代码取自 AWS 文档 SDK 示例 GitHub 存储库。请在[此处](https://github.com/awsdocs/aws-doc-sdk-examples/blob/master/javav2/example_code/rekognition/src/main/java/com/example/rekognition/DescribeCollection.java)查看完整示例。
```
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.rekognition.RekognitionClient;
import software.amazon.awssdk.services.rekognition.model.DescribeCollectionRequest;
import software.amazon.awssdk.services.rekognition.model.DescribeCollectionResponse;
import software.amazon.awssdk.services.rekognition.model.RekognitionException;
//snippet-end:[rekognition.java2.describe_collection.import]
/**
* Before running this Java V2 code example, set up your development environment, including your credentials.
*
* For more information, see the following documentation topic:
*
* https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
*/
public class DescribeCollection {
public static void main(String[] args) {
final String usage = "\n" +
"Usage: " +
" \n\n" +
"Where:\n" +
" collectionName - The name of the Amazon Rekognition collection. \n\n";
if (args.length != 1) {
System.out.println(usage);
System.exit(1);
}
String collectionName = args[0];
Region region = Region.US_EAST_1;
RekognitionClient rekClient = RekognitionClient.builder()
.region(region)
.credentialsProvider(ProfileCredentialsProvider.create("profile-name"))
.build();
describeColl(rekClient, collectionName);
rekClient.close();
}
// snippet-start:[rekognition.java2.describe_collection.main]
public static void describeColl(RekognitionClient rekClient, String collectionName) {
try {
DescribeCollectionRequest describeCollectionRequest = DescribeCollectionRequest.builder()
.collectionId(collectionName)
.build();
DescribeCollectionResponse describeCollectionResponse = rekClient.describeCollection(describeCollectionRequest);
System.out.println("Collection Arn : " + describeCollectionResponse.collectionARN());
System.out.println("Created : " + describeCollectionResponse.creationTimestamp().toString());
} catch(RekognitionException e) {
System.out.println(e.getMessage());
System.exit(1);
}
}
// snippet-end:[rekognition.java2.describe_collection.main]
}
```
------
#### [ AWS CLI ]
此 AWS CLI 命令显示 `describe-collection` CLI 操作的 JSON 输出。将 `collection-id` 的值更改为所需集合的 ID。将创建 Rekognition 会话的行中的`profile_name`值替换为您的开发人员资料的名称。
```
aws rekognition describe-collection --collection-id collection-name --profile profile-name
```
------
#### [ Python ]
此示例描述集合。
将值 `collection_id` 更改为所需集合的 ID。将创建 Rekognition 会话的行中的`profile_name`值替换为您的开发人员资料的名称。
```
# Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
# PDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-rekognition-developer-guide/blob/master/LICENSE-SAMPLECODE.)
import boto3
from botocore.exceptions import ClientError
def describe_collection(collection_id):
print('Attempting to describe collection ' + collection_id)
session = boto3.Session(profile_name='default')
client = session.client('rekognition')
try:
response = client.describe_collection(CollectionId=collection_id)
print("Collection Arn: " + response['CollectionARN'])
print("Face Count: " + str(response['FaceCount']))
print("Face Model Version: " + response['FaceModelVersion'])
print("Timestamp: " + str(response['CreationTimestamp']))
except ClientError as e:
if e.response['Error']['Code'] == 'ResourceNotFoundException':
print('The collection ' + collection_id + ' was not found ')
else:
print('Error other than Not Found occurred: ' + e.response['Error']['Message'])
print('Done...')
def main():
collection_id = 'collection-name'
describe_collection(collection_id)
if __name__ == "__main__":
main()
```
------
#### [ .NET ]
此示例描述集合。
将值 `collectionId` 更改为所需集合的 ID。
```
//Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
//PDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-rekognition-developer-guide/blob/master/LICENSE-SAMPLECODE.)
using System;
using Amazon.Rekognition;
using Amazon.Rekognition.Model;
public class DescribeCollection
{
public static void Example()
{
AmazonRekognitionClient rekognitionClient = new AmazonRekognitionClient();
String collectionId = "CollectionID";
Console.WriteLine("Describing collection: " + collectionId);
DescribeCollectionRequest describeCollectionRequest = new DescribeCollectionRequest()
{
CollectionId = collectionId
};
DescribeCollectionResponse describeCollectionResponse = rekognitionClient.DescribeCollection(describeCollectionRequest);
Console.WriteLine("Collection ARN: " + describeCollectionResponse.CollectionARN);
Console.WriteLine("Face count: " + describeCollectionResponse.FaceCount);
Console.WriteLine("Face model version: " + describeCollectionResponse.FaceModelVersion);
Console.WriteLine("Created: " + describeCollectionResponse.CreationTimestamp);
}
}
```
------
#### [ Node.js ]
```
//Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
//PDX-License-Identifier: MIT-0 (For details, see https://github.com/awsdocs/amazon-rekognition-developer-guide/blob/master/LICENSE-SAMPLECODE.)
import { DescribeCollectionCommand } from "@aws-sdk/client-rekognition";
import { RekognitionClient } from "@aws-sdk/client-rekognition";
import {fromIni} from '@aws-sdk/credential-providers';
// Set the AWS Region.
const REGION = "region-name"; //e.g. "us-east-1"
// Set the profile name
const profileName = "profile-name"
// Name the collection
const rekogClient = new RekognitionClient({region: REGION,
credentials: fromIni({profile: profileName,}),
});
// Name the collection
const collection_name = "collection-name"
const describeCollection = async (collectionName) => {
try {
console.log(`Attempting to describe collection named - ${collectionName}`)
var response = await rekogClient.send(new DescribeCollectionCommand({CollectionId: collectionName}))
console.log('Collection Arn:')
console.log(response.CollectionARN)
console.log('Face Count:')
console.log(response.FaceCount)
console.log('Face Model Version:')
console.log(response.FaceModelVersion)
console.log('Timestamp:')
console.log(response.CreationTimestamp)
return response; // For unit tests.
} catch (err) {
console.log("Error", err.stack);
}
};
describeCollection(collection_name)
```
------
## DescribeCollection 操作请求
`DescribeCollection` 的输入是所需集合的 ID，如下面的 JSON 示例所示。
```
{
"CollectionId": "MyCollection"
}
```
## DescribeCollection 操作响应
响应包括以下内容：
+ 在集合中索引的人脸数量 `FaceCount`。
+ 与集合一起使用的人脸模型版本，`FaceModelVersion`。有关更多信息，请参阅 [了解模型版本控制](face-detection-model.md)。
+ 集合的 Amazon 资源名称 `CollectionARN`。
+ 集合的创建时间和日期 `CreationTimestamp`。`CreationTimestamp` 的值是自 Unix 纪元时间到集合创建时间的毫秒数。Unix 纪元时间是 1970 年 1 月 1 日星期四，协调世界时 (UTC) 00:00:00。有关更多信息，请参阅 [Unix 时间](https://en.wikipedia.org/wiki/Unix_time)。
```
{
"CollectionARN": "arn:aws:rekognition:us-east-1:nnnnnnnnnnnn:collection/MyCollection",
"CreationTimestamp": 1.533422155042E9,
"FaceCount": 200,
"UserCount" : 20,
"FaceModelVersion": "1.0"
}
```