golang 代码扩展

来源：互联网发布：js判断是否为空 empty 编辑：程序博客网时间：2024/06/08 04:01
在写业务逻辑的时候如何写可扩展的代码？
之后加功能怎么不影响原来的代码？

-------------------以下是具体的应用------------------------------

//用户需要符合某些规则才能购买产品
//1.在某个时间段，2.产品订单金额大于一个数
//实现代码如下
//定义结构体（规则相关的参数）type Rule struct {Key stringTimeStart stringTimeEnd stringOrderAmount int}//map关系var muxRule map[string]func(rule *Rule) error//定义register，有新的规则则需要调用一下这个函数进行注册func registerBuy(key string, f func(rule *Rule) error) {if muxRule == nil {muxRule = make(map[string]func(rule *Rule) error)}if _, exist := muxRule[key]; exist {fmt.Println("handler exist")}muxRule[key] = f}//factory，调用实际方法，返回结果func factoryBuy(rule *Rule) error {return muxRule[rule.Key](rule)}func Test_rule(t *testing.T)  {//实现规则一rule1 := &Rule{Key:"rule1",TimeStart:"2010-01-01 OO:00:00",TimeEnd:"2020-01-01 OO:00:00",}opRule1 := func(rule *Rule) error {if rule.TimeStart > time.Now().Format("2006-01-02 15:04:05") || rule.TimeEnd < time.Now().Format("2006-01-02 15:04:05") {return errors.New("time is invalid")}return nil}//实现规则二rule2 := &Rule{Key:"rule2",OrderAmount:100,}//设传入参数用户购买金额为10amount := 10opRule2 := func(rule *Rule) error {if rule.OrderAmount != amount  {return errors.New("orderAmount is invalid")}return nil}registerBuy("rule1",opRule1)registerBuy("rule2",opRule2)ret1 := factoryBuy(rule1)ret2 := factoryBuy(rule2)if ret2 != nil || ret1 != nil {fmt.Printf("ret %v\n",ret1)fmt.Printf("ret %v\n",ret2)}else {fmt.Println("OK!")}}



输出结果：orderAmount is invalid
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