本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。 # 使用 CloudWatch 警示 ## 建立警示 若要根據 CloudWatch 指標建立警示，請呼叫 CloudWatchClient 的 `putMetricAlarm`方法，並將 [PutMetricAlarmRequest](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/cloudwatch/model/PutMetricAlarmRequest.html) 填入警示條件。 **匯入** ``` import software.amazon.awssdk.regions.Region; import software.amazon.awssdk.services.cloudwatch.CloudWatchClient; import software.amazon.awssdk.services.cloudwatch.model.Dimension; import software.amazon.awssdk.services.cloudwatch.model.PutMetricAlarmRequest; import software.amazon.awssdk.services.cloudwatch.model.ComparisonOperator; import software.amazon.awssdk.services.cloudwatch.model.Statistic; import software.amazon.awssdk.services.cloudwatch.model.StandardUnit; import software.amazon.awssdk.services.cloudwatch.model.CloudWatchException; ``` **Code** ``` public static void putMetricAlarm(CloudWatchClient cw, String alarmName, String instanceId) { try { Dimension dimension = Dimension.builder() .name("InstanceId") .value(instanceId).build(); PutMetricAlarmRequest request = PutMetricAlarmRequest.builder() .alarmName(alarmName) .comparisonOperator( ComparisonOperator.GREATER_THAN_THRESHOLD) .evaluationPeriods(1) .metricName("CPUUtilization") .namespace("AWS/EC2") .period(60) .statistic(Statistic.AVERAGE) .threshold(70.0) .actionsEnabled(false) .alarmDescription( "Alarm when server CPU utilization exceeds 70%") .unit(StandardUnit.SECONDS) .dimensions(dimension) .build(); cw.putMetricAlarm(request); System.out.printf( "Successfully created alarm with name %s", alarmName); } catch (CloudWatchException e) { System.err.println(e.awsErrorDetails().errorMessage()); System.exit(1); } } ``` 請參閱 GitHub 上的[完整範例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/f4eaf2b2971805cfb2b87a8e5ab408f83169432e/javav2/example_code/cloudwatch/src/main/java/com/example/cloudwatch/PutMetricAlarm.java)。 ## 列出警示 若要列出您已建立的 CloudWatch 警示，請使用 [DescribeAlarmsRequest](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/cloudwatch/model/DescribeAlarmsRequest.html) 呼叫 CloudWatchClient 的 `describeAlarms`方法，以用於設定結果的選項。 **匯入** ``` 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.DescribeAlarmsRequest; import software.amazon.awssdk.services.cloudwatch.model.DescribeAlarmsResponse; import software.amazon.awssdk.services.cloudwatch.model.MetricAlarm; ``` **Code** ``` public static void desCWAlarms( CloudWatchClient cw) { try { boolean done = false; String newToken = null; while(!done) { DescribeAlarmsResponse response; if (newToken == null) { DescribeAlarmsRequest request = DescribeAlarmsRequest.builder().build(); response = cw.describeAlarms(request); } else { DescribeAlarmsRequest request = DescribeAlarmsRequest.builder() .nextToken(newToken) .build(); response = cw.describeAlarms(request); } for(MetricAlarm alarm : response.metricAlarms()) { System.out.printf("\n Retrieved alarm %s", alarm.alarmName()); } if(response.nextToken() == null) { done = true; } else { newToken = response.nextToken(); } } } catch (CloudWatchException e) { System.err.println(e.awsErrorDetails().errorMessage()); System.exit(1); } System.out.printf("Done"); } ``` 您可以透過在 `describeAlarms` 傳回的 [DescribeAlarmsResponse](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/cloudwatch/model/DescribeAlarmsResponse.html) 上呼叫 `MetricAlarms`，來取得警示清單。 結果可能會*分頁*。若要擷取下一批次結果，請在回應物件上呼叫 `nextToken`，並使用字符值來建置新的請求物件。然後以新的請求再次呼叫 `describeAlarms` 方法。 **注意** 您也可以使用 CloudWatchClient 的 `describeAlarmsForMetric`方法擷取特定指標的警示。其用法類似於 `describeAlarms`。 請參閱 GitHub 上的[完整範例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/f4eaf2b2971805cfb2b87a8e5ab408f83169432e/javav2/example_code/cloudwatch/src/main/java/com/example/cloudwatch/DescribeAlarms.java)。 ## 刪除警示 若要刪除 CloudWatch 警示，請使用 [DeleteAlarmsRequest](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/cloudwatch/model/DeleteAlarmsRequest.html) 呼叫 CloudWatchClient 的 `deleteAlarms`方法，其中包含一或多個您要刪除的警示名稱。 **匯入** ``` 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.DeleteAlarmsRequest; ``` **Code** ``` public static void deleteCWAlarm(CloudWatchClient cw, String alarmName) { try { DeleteAlarmsRequest request = DeleteAlarmsRequest.builder() .alarmNames(alarmName) .build(); cw.deleteAlarms(request); System.out.printf("Successfully deleted alarm %s", alarmName); } catch (CloudWatchException e) { System.err.println(e.awsErrorDetails().errorMessage()); System.exit(1); } } ``` 請參閱 GitHub 上的[完整範例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/f4eaf2b2971805cfb2b87a8e5ab408f83169432e/javav2/example_code/cloudwatch/src/main/java/com/example/cloudwatch/DeleteAlarm.java)。 ## 其他資訊 + Amazon CloudWatch 《 使用者指南》中的[使用 Amazon CloudWatch 警示](https://docs.aws.amazon.com//AmazonCloudWatch/latest/monitoring/AlarmThatSendsEmail.html) + Amazon CloudWatch API 參考中的 [PutMetricAlarm](https://docs.aws.amazon.com//AmazonCloudWatch/latest/APIReference/API_PutMetricAlarm.html) + Amazon CloudWatch API 參考中的 [DescribeAlarms](https://docs.aws.amazon.com//AmazonCloudWatch/latest/APIReference/API_DescribeAlarms.html) + Amazon CloudWatch API 參考中的 [DeleteAlarms](https://docs.aws.amazon.com//AmazonCloudWatch/latest/APIReference/API_DeleteAlarms.html)