Go使用协程批量获取数据加快接口返回速度

package main

import (
   "fmt"
   "time"
)

func add2(a, b int, ch chan int) {
   c := a + b
   fmt.Printf("%d + %d = %d\n", a, b, c)
   ch <- 1 //执行完了就写一条表示自己完成了
}

func main() {
   start := time.Now()
   chs := make([]chan int, 10)
   for i := 0; i < 10; i++ {
      chs[i] = make(chan int)
      go add2(1, i, chs[i]) //分配了10个协程出去了
   }
   for _, ch := range chs {
      <-ch //循环等待，要每个完成才能继续，不然就等待
   }
   end := time.Now()
   consume := end.Sub(start).Seconds()
   fmt.Println("程序执行耗时(s)：", consume)
}

package main

import (
   "fmt"
   "sync"
)

func addNum(a, b int, deferFunc func()) {
   defer func() {
      deferFunc()
   }()
   c := a + b
   fmt.Printf("%d + %d = %d\n", a, b, c)
}

func main() {
   var wg sync.WaitGroup
   wg.Add(10) //等于发了10个令牌
   for i := 0; i < 10; i++ {
      go addNum(i, 1, wg.Done) //每次执行都消耗令牌
   }
   wg.Wait() //等待令牌消耗完
}

func GetManyBase(userIds []int64) []UserBase {
   userCaches := make([]UserBase, len(userIds))

   var wg sync.WaitGroup
   for index, userId := range userIds {
      wg.Add(1)
      go func(index int, userId int64, userCaches []UserBase) {
         userCaches[index] = NewUserCache(userId).GetBase() 
         wg.Done()
      }(index, userId, userCaches)
   }
   wg.Wait()

   return userCaches
}

func GetManyBase(userIds []int64) []UserBase {
	userCaches := make([]UserBase, len(userIds))

	var scene sync.Map

	var wg sync.WaitGroup
	for index, userId := range userIds {
		wg.Add(1)
		go func(index int, userId int64, userCaches []UserBase) {
			scene.Store(userId, NewUserCache(userId).GetBase())
			wg.Done()
		}(index, userId, userCaches)
	}
	wg.Wait()

	i := 0
	for _, userId := range userIds {
		if value, ok := scene.Load(userId); ok {
			userCaches[i] = value.(UserBase)
		}
		i++
	}

	return userCaches
}