实现多goroutine之间的发布和订阅

实现多goroutine之间的发布和订阅

一、实现思路

• 一个发布者，三个订阅者
• 发布者需要跟每个订阅者之间，都要建立一个chan
• 调用发布方法后，三个订阅者都能收到发布的信息
• 在发布和接收之间，增加暂停，使运行结果更加直观

二、实现代码

func Test_Main(t *testing.T) {
	sl := NewSubList()

	// 增加A的订阅
	sl.Subscribe("A", make(Broadcast))
	// 增加B的订阅
	sl.Subscribe("B", make(Broadcast))
	// 增加C的订阅
	sl.Subscribe("C", make(Broadcast))
	Sleep(3)
	sl.PublishMessage("Hello World!")
	Sleep(3)
	sl.PublishMessage("Golang very good!")

	sl.Unsubscribe("B")
	Sleep(3)
	sl.PublishMessage("Golang so easy!")
}

type Broadcast chan string

type SubList struct {
	CH map[string]Broadcast
	sync.RWMutex
}

func NewSubList() *SubList {
	s := &SubList{}
	s.CH = make(map[string]Broadcast) //所有channel
	return s
}

// Subscribe 订阅
func (s *SubList) Subscribe(name string, bc Broadcast) {
	s.Lock()
	s.CH[name] = bc
	s.Unlock()
	go s.ListeningBroadcast(name, bc)
}

// Unsubscribe 取消订阅
func (s *SubList) Unsubscribe(name string) {
	s.Lock()
	delete(s.CH, name)
	s.Unlock()
}

//发布消息
func (s *SubList) PublishMessage(message string) {
	s.RLock()
	for k, v := range s.CH {
		v <- message
		fmt.Println("向 ", k, " 发送 ", message)
	}
	s.RUnlock()
}

// ListeningBroadcast 监听信息
func (s *SubList) ListeningBroadcast(name string, bc Broadcast) {
	for {
		message := <-bc
		time.Sleep(time.Duration(1) * time.Second)
		fmt.Println(name, " 收到 ", message)
	}
}

func Sleep(i int64)  {
	fmt.Println("等待3秒......")
	time.Sleep(time.Duration(i) * time.Second)
}