def winningSym = /(?<=winline":)[0-9]+/
String s = """{"Id":1,"winline":5,"Winnings":50000, some random text, "winline":4, more random text, "winline":7, more stuff}"""
def res = s.findAll(winningSym)
println(res)
ZGVmIHdpbm5pbmdTeW0gPSAvKD88PXdpbmxpbmUiOilbMC05XSsvClN0cmluZyBzID0gIiIieyJJZCI6MSwid2lubGluZSI6NSwiV2lubmluZ3MiOjUwMDAwLCBzb21lIHJhbmRvbSB0ZXh0LCAid2lubGluZSI6NCwgbW9yZSByYW5kb20gdGV4dCwgIndpbmxpbmUiOjcsIG1vcmUgc3R1ZmZ9IiIiCmRlZiByZXMgPSBzLmZpbmRBbGwod2lubmluZ1N5bSkKcHJpbnRsbihyZXMpCg==