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golang包循环引用的几种解决方案总结

作者:云满笔记

golang有包循环引用问题,用过的应该都知道,下面这篇文章主要给大家介绍了关于golang包循环引用的几种解决方案,文中通过实例代码介绍的非常详细,需要的朋友可以参考下

1. golang 包循环引用的几种解决方案

1.1. 前言

golang 为了加速编译, 不允许包循环引用。通常来说, 只要你的包规划得好, 严格规范单向调用链 (如控制层 -> 业务层 ->数据层), 一般不会出现包循环引用问题。当然现实业务往往不会这么理想, 同层级之间的不同包经常需要互相引用, 下面我就分享几种解决包循环引用的方案。

1.2. 新建公共接口包(父包), 将需要循环调用的函数或方法抽象为接口

package_i

package package_i
 
type PackageAInterface interface {
	PrintA()
}
 
type PackageBInterface interface {
	PrintB()
}

package_a

package package_a
 
import (
	"cycle/package_i"
	"fmt"
)
 
type PackageA struct {
	B package_i.PackageBInterface
}
 
func (a PackageA) PrintA() {
	fmt.Println("I'm a!")
}
 
func (a PackageA) PrintAll() {
	a.PrintA()
	a.B.PrintB()
}

package_b

package package_b
 
import (
	"cycle/package_i"
	"fmt"
)
 
type PackageB struct {
	A package_i.PackageAInterface
}
 
func (b PackageB) PrintB() {
	fmt.Println("I'm b!")
}
 
func (b PackageB) PrintAll() {
	b.PrintB()
	b.A.PrintA()
}

main

package main
 
import (
	"cycle/package_a"
	"cycle/package_b"
)
 
func main() {
	a := new(package_a.PackageA)
	b := new(package_b.PackageB)
        a.B = b
        b.A = a
	a.PrintAll()
	b.PrintAll()
}

1.3. 新建公共组合包(子包), 在组合包中组合调用

package_c

package package_c
 
import (
	"cycle/package_a"
	"cycle/package_b"
)
 
type CombileAB struct {
	A *package_a.PackageA
	B *package_b.PackageB
}
 
func (c CombileAB) PrintAll() {
	c.A.PrintA()
	c.B.PrintB()
}

main

package main
 
import (
	"cycle/package_a"
	"cycle/package_b"
	"cycle/package_c"
)
 
func main() {
	a := new(package_a.PackageA)
	b := new(package_b.PackageB)
	c := new(package_c.CombileAB)
	c.A = a
	c.B = b
	c.PrintAll()
}

1.4. 全局存储需要相互依赖的函数, 通过关键字进行调用

callback_mgr

package callback_mgr
 
import (
	"fmt"
	"reflect"
)
 
var callBackMap map[string]interface{}
 
func init() {
	callBackMap = make(map[string]interface{})
}
 
func RegisterCallBack(key string, callBack interface{}) {
	callBackMap[key] = callBack
}
 
func CallBackFunc(key string, args ...interface{}) []interface{} {
	if callBack, ok := callBackMap[key]; ok {
		in := make([]reflect.Value, len(args))
		for i, arg := range args {
			in[i] = reflect.ValueOf(arg)
		}
		outList := reflect.ValueOf(callBack).Call(in)
		result := make([]interface{}, len(outList))
		for i, out := range outList {
			result[i] = out.Interface()
		}
		return result
	} else {
		panic(fmt.Errorf("callBack(%s) not found", key))
	}
}

package_a

package package_a
 
import (
	"cycle/callback_mgr"
	"fmt"
)
 
func init() {
	callback_mgr.RegisterCallBack("getA", new(PackageA).GetA)
}
 
type PackageA struct {
}
 
func (a PackageA) GetA() string {
	return "I'm a!"
}
 
func (a PackageA) PrintAll() {
	fmt.Println(a.GetA())
	fmt.Println(callback_mgr.CallBackFunc("getB")[0].(string))
}

package_b

package package_b
 
import (
	"cycle/callback_mgr"
	"fmt"
)
 
func init() {
	callback_mgr.RegisterCallBack("getB", new(PackageB).GetB)
}
 
type PackageB struct {
}
 
func (b PackageB) GetB() string {
	return "I'm b!"
}
 
func (b PackageB) PrintAll() {
	fmt.Println(b.GetB())
	fmt.Println(callback_mgr.CallBackFunc("getA")[0].(string))
}

main

package main
 
import (
	"cycle/package_a"
	"cycle/package_b"
)
 
func main() {
	a := new(package_a.PackageA)
	b := new(package_b.PackageB)
	a.PrintAll()
	b.PrintAll()
}

1.5. 不需要回调结果的可以通过事件总线 (eventBus) 解耦

eventBus

package eventBus
 
import (
	"github.com/asaskevich/EventBus"
)
 
var globalEventBus EventBus.Bus
 
func init() {
	globalEventBus = EventBus.New()
}
 
func Subscribe(topic string, fn interface{}) error {
	return globalEventBus.Subscribe(topic, fn)
}
 
func SubscribeAsync(topic string, fn interface{}, transactional bool) error {
	return globalEventBus.SubscribeAsync(topic, fn, transactional)
}
 
func Publish(topic string, args ...interface{}) {
	globalEventBus.Publish(topic, args...)
}

package_a

package package_a
 
import (
	"cycle/eventBus"
	"fmt"
)
 
func init() {
	eventBus.Subscribe("PrintA", new(PackageA).PrintA)
}
 
type PackageA struct {
}
 
func (a PackageA) PrintA() {
	fmt.Println("I'm a!")
}
 
func (a PackageA) PrintAll() {
	a.PrintA()
	eventBus.Publish("PrintB")
}

package_b

package package_b
 
import (
	"cycle/eventBus"
	"fmt"
)
 
func init() {
	eventBus.Subscribe("PrintB", new(PackageB).PrintB)
}
 
type PackageB struct {
}
 
func (b PackageB) PrintB() {
	fmt.Println("I'm b!")
}
 
func (b PackageB) PrintAll() {
	b.PrintB()
	eventBus.Publish("PrintA")
}

总结

到此这篇关于golang包循环引用的几种解决方案的文章就介绍到这了,更多相关golang包循环引用内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家!

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