go - 关于goroutine并发的问题

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，但它真正做的是等待运行

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  

我期望的输出

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

基本上，您有:

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。然后循环等待，通过 channel 接收 <-cBD , 直到 goroutine 通过 cBD <- data[k] 发送到 channel ，一秒后。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