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# 从中获取指标 CloudWatch
<a name="examples-cloudwatch-get-metrics"></a>

## 列出指标
<a name="listing-metrics"></a>

要列出 CloudWatch 指标，请创建[ListMetricsRequest](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/cloudwatch/model/ListMetricsRequest.html)并调用 CloudWatchClient's `listMetrics` 方法。您可以使用 `ListMetricsRequest` 通过命名空间、指标名称或维度筛选返回的指标。

**注意**  
 AWS 服务发布的指标和维度列表可在 Amazon CloudWatch 用户指南的[Amazon CloudWatch 指标和维度参考](https://docs.aws.amazon.com//AmazonCloudWatch/latest/monitoring/aws-services-cloudwatch-metrics.html)中找到。

 **导入** 

```
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.cloudwatch.CloudWatchClient;
import software.amazon.awssdk.services.cloudwatch.model.CloudWatchException;
import software.amazon.awssdk.services.cloudwatch.model.ListMetricsRequest;
import software.amazon.awssdk.services.cloudwatch.model.ListMetricsResponse;
import software.amazon.awssdk.services.cloudwatch.model.Metric;
```

 **代码** 

```
    public static void listMets( CloudWatchClient cw, String namespace) {

        boolean done = false;
        String nextToken = null;

        try {
            while(!done) {

                ListMetricsResponse response;

                if (nextToken == null) {
                   ListMetricsRequest request = ListMetricsRequest.builder()
                        .namespace(namespace)
                        .build();

                 response = cw.listMetrics(request);
                } else {
                  ListMetricsRequest request = ListMetricsRequest.builder()
                        .namespace(namespace)
                        .nextToken(nextToken)
                        .build();

                response = cw.listMetrics(request);
            }

            for (Metric metric : response.metrics()) {
                System.out.printf(
                        "Retrieved metric %s", metric.metricName());
                System.out.println();
            }

            if(response.nextToken() == null) {
                done = true;
            } else {
                nextToken = response.nextToken();
            }
        }

        } catch (CloudWatchException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
```

[ListMetricsResponse](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/cloudwatch/model/ListMetricsResponse.html)通过调用其`getMetrics`方法返回指标。

结果可以*分页*。要检索下一批结果，请对响应对象调用 `nextToken` 并使用该令牌值构建新的请求对象。然后使用新请求再次调用 `listMetrics` 方法。

请参阅上的[完整示例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/f4eaf2b2971805cfb2b87a8e5ab408f83169432e/javav2/example_code/cloudwatch/src/main/java/com/example/cloudwatch/ListMetrics.java) GitHub。

## 更多信息
<a name="more-information"></a>
+  [ListMetrics](https://docs.aws.amazon.com//AmazonCloudWatch/latest/APIReference/API_ListMetrics.html)在 Amazon CloudWatch API 参考中