单例模式

static Data* instance_ = NULL;
Data* IMData::getInstance()
{
if (!instance_) {
instance_ = new Data;
}
return instance_;
}

GameData  = {}
function GameData:new(o)
o = o or {}
setmetatable(o,self)
self.__index = self
return o
end

function GameData:getInstance()
if self.instance == nil then
self.instance = self:new()
end
return self.instance
end