golang包循環(huán)引用的幾種解決方案總結(jié)

更新時間：2022年09月19日 09:03:52 作者：云滿筆記

golang有包循環(huán)引用問題,用過的應(yīng)該都知道,下面這篇文章主要給大家介紹了關(guān)于golang包循環(huán)引用的幾種解決方案,文中通過實例代碼介紹的非常詳細,需要的朋友可以參考下

1.1. 前言
1.2. 新建公共接口包(父包), 將需要循環(huán)調(diào)用的函數(shù)或方法抽象為接口
1.3. 新建公共組合包(子包), 在組合包中組合調(diào)用
1.4. 全局存儲需要相互依賴的函數(shù), 通過關(guān)鍵字進行調(diào)用
1.5. 不需要回調(diào)結(jié)果的可以通過事件總線 (eventBus) 解耦

總結(jié)

1. golang 包循環(huán)引用的幾種解決方案

1.1. 前言

golang 為了加速編譯, 不允許包循環(huán)引用。通常來說, 只要你的包規(guī)劃得好, 嚴(yán)格規(guī)范單向調(diào)用鏈 (如控制層 -> 業(yè)務(wù)層 ->數(shù)據(jù)層), 一般不會出現(xiàn)包循環(huán)引用問題。當(dāng)然現(xiàn)實業(yè)務(wù)往往不會這么理想, 同層級之間的不同包經(jīng)常需要互相引用, 下面我就分享幾種解決包循環(huán)引用的方案。

1.2. 新建公共接口包(父包), 將需要循環(huán)調(diào)用的函數(shù)或方法抽象為接口

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. 新建公共組合包(子包), 在組合包中組合調(diào)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. 全局存儲需要相互依賴的函數(shù), 通過關(guān)鍵字進行調(diào)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. 不需要回調(diào)結(jié)果的可以通過事件總線 (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")
}