Question

我有一个类似下面的Lua类。我使用json序列化对象并将其放在键值存储中。我能够序列化对象并将其成功放入键值存储，但在从键值存储中检索对象后，我无法调用该对象的任何方法。我理解json模块在编码时跳过方法，而我的对象在解码后没有方法。

在将对象从json解码为lua后，有没有办法将方法附加到类？有些东西类似于C语言中的函数指针。

local class_name = "user_object";
user_object = {};  --user class 


function user_object.new (mobile, password, uid)

        local self = {};
        self.mobile = mobile;
        self.uid    = uid; -- generate a uid which is a running number.
        self.password = password;
        self.messages_sent = 0;
        self.put_request_count = 0;
        self.get_request_count = 0;
        self.last_time_active = "";
        self.get_tickets = {};
        self.put_tickets = {};
        self.group_message_stream = {};
        self.group_ownerships = {}; -- group names which he is owner of 
        self.group_memberships = {}; -- group names  which he is member of 
        self.sent_poke_count = 0;
        self.sent_poke_stream = {};
        self.recv_poke_count = 0;
        self.recv_poke_stream = {};

        function self:add_put_ticket(ticketid)
                table.insert(self.put_tickets, ticketid);
                self:incr_put_count();
                self:save();
                return;
        end 

        function self:add_get_ticket(ticketid)
                table.insert(self.get_tickets, ticketid);
                self:incr_get_count();
                self:save();
                return;
        end

Answer 1

您可以使用元表来完成此操作。

user = { name = 'ponzao' } -- Just a table with values.
User = {}                  -- Table containing the functions.
function User:allCapsName() return self.name:upper() end -- A method.
setmetatable(user, {__index = User}) -- For unavailable keys all calls are dispatched to User.
print(user:allCapsName()) --> "PONZAO"

Answer 2

Lua中的函数是第一类对象，可以在任何变量中存储函数。这条线

function self:add_put_ticket(ticketid)

相当于

self.add_put_ticket = function (self, ticketid)

从那里开始，应该明白该做什么：在可以访问的地方定义所需的方法，并在反序列化后将它们分配到适当的字段

从json解码后无法调用方法

2 个答案: