关于goroutine并发的麻烦

Question

我在goroutine并发方面遇到了一些麻烦。在我的期望中，它应该异步运行并几乎同时打印出来，但它真正做的是在等待的情况下运行

我的测试代码

package main
type batchD []string
var cBD = make(chan batchD, 6)
func main() {
runtime.GOMAXPROCS(runtime.NumCPU())
data := [][]string{}
data = append(data, []string{"71", "40348270", "6", "win888e", "6", "1", "N", "127.0.0.1"})
data = append(data, []string{"71", "40348270", "6", "win888e", "6", "1", "N", "127.0.0.1"})
data = append(data, []string{"71", "40348270", "6", "win888e", "6", "1", "N", "127.0.0.1"})
data = append(data, []string{"71", "129499244", "6", "win888e", "6", "1", "N", "127.0.0.1"})
data = append(data, []string{"71", "40348270", "6", "win888e", "6", "1", "N", "127.0.0.1"})
data = append(data, []string{"71", "40348270", "6", "win888e", "6", "1", "N", "127.0.0.1"})
for k,v := range data {
go func() {
fmt.Println(k,v)
//batchD{}.BatchDeposit(v[0],v[1],v[2],v[3],v[4],v[5],v[6],v[7])
delay()
cBD <- data[k]
}()
<-cBD
}
}
func delay() {
time.Sleep(1 * time.Second)
t := Basic.NowTime("Taipei")
fmt.Println(t)
}

我得到的输出

0 [71 40348270 6 win888e 6 1 N 127.0.0.1]  
2017-08-16 12:00:40  
1 [71 40348270 6 win888e 6 1 N 127.0.0.1]  
2017-08-16 12:00:41  
2 [71 40348270 6 win888e 6 1 N 127.0.0.1]  
2017-08-16 12:00:42  
3 [71 129499244 6 win888e 6 1 N 127.0.0.1]  
2017-08-16 12:00:43  
4 [71 40348270 6 win888e 6 1 N 127.0.0.1]  
2017-08-16 12:00:44  
5 [71 40348270 6 win888e 6 1 N 127.0.0.1]  
2017-08-16 12:00:45  

我预期的输出

0 [71 40348270 6 win888e 6 1 N 127.0.0.1]  
2017-08-16 12:00:40  
1 [71 40348270 6 win888e 6 1 N 127.0.0.1]  
2017-08-16 12:00:40  
2 [71 40348270 6 win888e 6 1 N 127.0.0.1]  
2017-08-16 12:00:40  
3 [71 129499244 6 win888e 6 1 N 127.0.0.1]  
2017-08-16 12:00:40  
4 [71 40348270 6 win888e 6 1 N 127.0.0.1]  
2017-08-16 12:00:40  
5 [71 40348270 6 win888e 6 1 N 127.0.0.1]  
2017-08-16 12:00:40  

任何建议或提示都会有所帮助。谢谢。

Answer 1

本质上，你有：

var cBD = make(chan batchD, 6)
for k := range data {
go func() {
time.Sleep(1 * time.Second)
fmt.Println(time.Now().Format("2006-01-02 15:04:05"))
cBD <- data[k]
}()
<-cBD
}

每个循环启动一个 goroutine。然后循环通过通道接收<-cBD等待，直到goroutine在一秒钟后通过cBD <- data[k]发送到通道。例如

2017-08-16 02:52:46
2017-08-16 02:52:47
2017-08-16 02:52:48
2017-08-16 02:52:49
2017-08-16 02:52:50
2017-08-16 02:52:51