1、切换

package main

import "fmt"
import "time"

func genData1(ch chan int) {
    for i :=2; ; i++ {
        ch <- i * 2
    }
}

func genData2(ch chan int) {
    for i :=2; ; i++ {
        ch <- i / 2
    }
}

func getData(ch1 chan int, ch2 chan int) {
    for {
        select {
            case v := <-ch1:
                fmt.Printf("Received on channel 1: %d\n", v)
            case v := <-ch2:
                fmt.Printf("Received on channel 2: %d\n", v)
        }
    }
}

func main() {
    ch1 := make(chan int)
    ch2 := make(chan int)

    go genData1(ch1)
    go genData2(ch2)
    go getData(ch1, ch2)
    time.Sleep(1e9)
}