dubbo beat trigger JSONException

[theonefx]

the body of beat request is :
beat={"cluster":"DEFAULT","ip":"30.5.125.57","metadata":{"dubbo.metadata-service.urls":"[ "dubbo://30.128.116.47:20880/com.alibaba.cloud.dubbo.service.DubboMetadataService?anyhost=true&application=spring-cloud-alibaba-dubbo-server&bind.ip=30.128.116.47&bind.port=20880&deprecated=false&dubbo=2.0.2&dynamic=true&generic=false&group=spring-cloud-alibaba-dubbo-server&interface=com.alibaba.cloud.dubbo.service.DubboMetadataService&methods=getAllServiceKeys,getServiceRestMetadata,getExportedURLs,getAllExportedURLs&pid=2362&qos.enable=false&release=2.7.4.1&revision=1.0.0&side=provider&timestamp=1585139980414&version=1.0.0" ]","dubbo.protocols.dubbo.port":"20880","preserved.register.source":"SPRING_CLOUD"},"period":5000,"port":20880,"scheduled":false,"serviceName":"DEFAULT_GROUP@@spring-cloud-alibaba-dubbo-server","stopped":false,"weight":1.0}