lua中按照_id　查询

function convertHexStringToNormal( str )
return (str:gsub('..', function (cc)
return string.char(tonumber(cc, 16))
end))
end

local object_id = require "resty.mongol.object_id"
r = col:find_one({_id = object_id.new(convertHexStringToNormal("53c24a247661670d08000000"))})

https://github.com/bigplum/lua-resty-mongol/issues/33