How can i use the timestamp in the source file rather than the timestamp generate automatically

Elastic Stack Beats
8

Thanks very much , after put below format it works!

  "date": {
    "field": "processtime",
    "formats": ["yyyy-MM-dd HH:mm:ss"]

      "@timestamp": "2018-01-06T15:51:23.000Z",
      "beat": {
        "hostname": "systemx",
        "name": "RestReviews",
        "version": "5.1.1"
      },
      "processtime": "2018-01-06 15:51:23",
      "rttype": "inchannels",
      "trackingid": "999711"
    },