golang select 选择器
常规模式:
package main import ( "fmt" "strconv" ) func main() { var chs1 = make(chan int) var chs2 = make(chan float64) var chs3 = make(chan string) var ch4close = make(chan int) defer close(ch4close) go func(c chan int,ch4close chan int) { for i := 0; i < 5; i++ { c <- i } close(c) ch4close <- 1 }(chs1,ch4close) go func(c chan float64,ch4close chan int) { for i := 0; i < 5; i++ { c <- float64(i) + 0.1 } close(c) ch4close <- 1 }(chs2,ch4close) go func(c chan string,ch4close chan int) { for i := 0; i < 5; i++ { c <- "string:" + strconv.Itoa(i) } close(c) ch4close <- 1 }(chs3,ch4close) done := 0 finished := 0 for finished < 3 { select { case v,ok := <-chs1: if ok { done = done + 1 fmt.Println(0,v) } case v,ok := <-chs2: if ok { done = done + 1 fmt.Println(1,ok := <-chs3: if ok { done = done + 1 fmt.Println(2,v) } case _,ok := <- ch4close: if ok { finished = finished+1 } } } fmt.Println("Done",done) }
reflect设计
package main import ( "fmt" "reflect" "strconv" ) func main() { var chs1 = make(chan int) var chs2 = make(chan float64) var chs3 = make(chan string) var ch4close = make(chan int) defer close(ch4close) go func(c chan int,ch4close) var selectCase = make([]reflect.SelectCase,4) selectCase[0].Dir = reflect.SelectRecv selectCase[0].Chan = reflect.ValueOf(chs1) selectCase[1].Dir = reflect.SelectRecv selectCase[1].Chan = reflect.ValueOf(chs2) selectCase[2].Dir = reflect.SelectRecv selectCase[2].Chan = reflect.ValueOf(chs3) selectCase[3].Dir = reflect.SelectRecv selectCase[3].Chan = reflect.ValueOf(ch4close) done := 0 finished := 0 for finished < len(selectCase)-1 { chosen,recv,recvOk := reflect.Select(selectCase) if recvOk { done = done+1 switch chosen { case 0: fmt.Println(chosen,recv.Int()) case 1: fmt.Println(chosen,recv.Float()) case 2: fmt.Println(chosen,recv.String()) case 3: finished = finished+1 done = done-1 // fmt.Println("finished\t",finished) } } } fmt.Println("Done",done) }