lua向文件中写入数据，进行记录

function readfile(path)
      local file = io.open(path, "r")
      if file then
        local content = file:read("*a")
        io.close(file)
        return content
      end
      return nil
end

function writefile(path, content, mode)
      mode = mode or "w+b"
      local file = io.open(path, mode)
      if file then
        if file:write(content) == nil then return false end
        io.close(file)
        return true
      else
        return false
      end
end
--文件读写测试
local a = {x=1,y=2,z=3}
local str = json.encode(a)                --将lua表编码为json格式字符串
local path = cc.FileUtils:getInstance():getWritablePath()
    path = path..filename                 --得到可读写文件的路径
    writefile(path,str,r)                 --将数据写入文件
local b = readfile(path)                  --从文件中读取数据
    printf(b)
end


2. 文件操作示例代码
local path = cc.FileUtils:getInstance():getWritablePath()
cc.FileUtils:getInstance():writeToFile({key="value"}, paht.."filename")     --读取数据的方式
print(ret.key) 
lcoal ret = cc.FileUtils:getInstance():getValueMapFromFile(Path.."filename")  --读取数据的方式2
print(str)
local str = cc.FileUtils:getInstance():getStringFromFile(path.."filename")