How to solve spring metrics data (in json format ) in logstash

[AndyLin (andy)]

I was new to ELKB stack.
I use http beat to get the metrics data from my spring boot app, and send it to logstash for solving.
But I can not find any helpful info to solve my json data to the data I want for sending to elastic search.
Here is my metric data(after solved by logstash ):

    {
    "@timestamp" => 2018-12-28T02:23:01.003Z,
          "beat" => {
        "hostname" => "hostname",
            "name" => "name",
         "version" => "4.0.0"
    },
      "response" => {
           "headers" => {
                              "Date" => "Fri, 28 Dec 2018 02:23:01 GMT",
                            "Pragma" => "no-cache",
                   "X-Frame-Options" => "DENY",
                  "X-Xss-Protection" => "1; mode=block",
            "X-Content-Type-Options" => "nosniff",
                           "Expires" => "0",
                     "Cache-Control" => "no-cache, no-store, max-age=0, must-re
alidate",
               "Content-Disposition" => "inline;filename=f.txt",
                      "Content-Type" => "application/json;charset=UTF-8"
        },
        "statusCode" => 200,
          "jsonBody" => {
             "measurements" => [
                [0] {
                    "statistic" => "VALUE",
                        "value" => 32
                }
            ],
            "name" => "jvm.threads.live",
            "availableTags" => [ ]
        }
    },
          "type" => "httpbeat",
      "@version" => "1",
          "host" => "hostname",
       "request" => {
        "headers" => {
            "Accept" => "application/json"
        },
         "method" => "get",
            "url" => "http://localhost:8080/actuator/metrics/jvm.threads.live"
    },
        "fields" => {
        "appid" => "appid"
    },
          "tags" => [
        [0] "beats_input_raw_event"
    ]
}

and my logstash config do nothig, the config is

input {
    beats {
        port => "5044"
    }
}
filter {
	json {
		source => "jsonBody"
		remove_field => [ "headers" ]  #seems not work for remove the field
	}
}
output {
    stdout { codec => rubydebug }
}

and the data I want is,

 "jsonBody" => {
             "measurements" => [
                [0] {
                    "statistic" => "VALUE",
                        "value" => 32
                }
            ],
            "name" => "jvm.threads.live",
            "availableTags" => []
 }

and also the timestamp.

So can any one help. Any tutorial or logstash config is fine.
Thanks.