在AWS CDK中，如果想要使用ApplicationLoadBalancedFargateService来创建Fargate服务，并在服务中设置容量提供程序策略，需要使用自定义构造函数来实现。

具体实现方法如下所示：

from aws_cdk import aws_ec2 as ec2
from aws_cdk import aws_ecs_patterns as ecs_patterns
from aws_cdk import core

class MyFargateService(ecs_patterns.ApplicationLoadBalancedFargateService):
    def __init__(self, scope: core.Construct, id: str, *,
                 task_definition: ecs_patterns.FargateTaskDefinition,
                 desired_count: int = 1,
                 listener_port: int = 80,
                 vpc: ec2.IVpc,
                 capacity_provider_strategies=None,
                 task_subnets=None,
                 health_check_grace_period=None,
                 platform_version=None,
                 cpu=None,
                 memory_limit_mib=None,
                 memory_reservation_mib=None,
                 deployment_controller_type=None,
                 deployment_controller=None,
                 cloud_map_options=None,
                 assign_public_ip=None,
                 service_name=None,
                 target_group_name=None,
                 protocol=None,
                 domain_name=None,
                 domain_zone=None,
                 redirect_http=None) -> None:

        super().__init__(scope, id, task_definition=task_definition, desired_count=desired_count,
                         listener_port=listener_port, vpc=vpc, task_subnets=task_subnets,
                         health_check_grace_period=health_check_grace_period, platform_version=platform_version,
                         cpu=cpu, memory_limit_mib=memory_limit_mib,
                         memory_reservation_mib=memory_reservation_mib,
                         deployment_controller_type=deployment_controller_type,
                         deployment_controller=deployment_controller,
                         cloud_map_options=cloud_map_options, assign_public_ip=assign_public_ip,
                         service_name=service_name, target_group_name=target_group_name, protocol=protocol,
                         domain_name=domain_name, domain_zone=domain_zone, redirect_http=redirect_http)

        self.service.enable_scaling()
        if capacity_provider_strategies is not None:
            self.service.add_capacity_provider_strategy(*capacity_provider_strategies)