【Go channel如何控制goroutine并发执行顺序？】

多个goroutine并发执行时，每一个goroutine抢到处理器的时间点不一致，gorouine的执行本身不能保证顺序。即代码中先写的gorouine并不能保证先执行

思路：使用channel进行通信通知，用channel去传递信息，从而控制并发执行顺序

package main

import (
    "fmt"
    "sync"
    "time"
)

var wg sync.WaitGroup

func main() {
    ch1 := make(chan struct{}, 1)
    ch2 := make(chan struct{}, 1)
    ch3 := make(chan struct{}, 1)
    ch1 <- struct{}{}
    wg.Add(3)
    start := time.Now().Unix()
    go print("gorouine1", ch1, ch2)
    go print("gorouine2", ch2, ch3)
    go print("gorouine3", ch3, ch1)
    wg.Wait()
    end := time.Now().Unix()
    fmt.Printf("duration:%d\n", end-start)
}

func print(gorouine string, inputchan chan struct{}, outchan chan struct{}) {
    // 模拟内部操作耗时
    time.Sleep(1 * time.Second)
    select {
    case <-inputchan:
        fmt.Printf("%s\n", gorouine)
        outchan <- struct{}{}
    }
    wg.Done()
}

• 输出：

gorouine1
gorouine2
gorouine3
duration:1