go协程实例-2

秒速五厘米 2022-03-21 03:15 266阅读 0赞

package main
    
    import (
    	"fmt"
    )
    
    type worker struct {
    	channel chan int
    	done chan bool
    }
    
    func main() {
    	var workers [10]worker
    
    	for i:=0;i<10 ;i++  {
    		workers[i]=worker{
    			make(chan int),
    			make(chan bool),
    		}
    		go printNum(i,workers[i])
    	}
    	for i,w:=range workers  {
    		w.channel<- 'a'+i
    	}
    	for i,w:=range workers {
    		w.channel<- 'A'+i
    	}
    
    	for _,w:=range workers {
    		<-w.done
    		<-w.done
    	}
    	//保障协程运行完毕，主协程main运行结束之后，其他协程也全部结束
    	//time.Sleep(time.Duration(time.Millisecond))
    }
    func printNum(i int,w worker){
    	for{
    		//io操作会进行调度
    		fmt.Println(i,"got num:",<-w.channel)
    		w.done<-true
    	}
    }

在上面的程序中运行报错:

GOROOT=C:\Go #gosetup
    GOPATH=E:\GoProgram\awsomeproject;E:\GoProgram\awsomeproject\src\video_server_1_5;E:\GoProgram;C:\Users\123\go #gosetup
    C:\Go\bin\go.exe build -i -o C:\Users\123\AppData\Local\Temp\___go_build_testChannel_go.exe E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go #gosetup
    "E:\goland\GoLand 2018.1.6\bin\runnerw.exe" C:\Users\123\AppData\Local\Temp\___go_build_testChannel_go.exe #gosetup
    fatal error: all goroutines are asleep - deadlock!
    0 got num: 97
    1 got num: 98
    2 got num: 99
    3 got num: 100
    4 got num: 101
    5 got num: 102
    6 got num: 103
    7 got num: 104
    8 got num: 105
    9 got num: 106
    
    goroutine 1 [chan send]:
    main.main()
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:26 +0x1d1
    
    goroutine 18 [chan send]:
    main.printNum(0x0, 0xc042048060, 0xc0420480c0)
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:40 +0x11c
    created by main.main
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:20 +0xf8
    
    goroutine 19 [chan send]:
    main.printNum(0x1, 0xc042048120, 0xc042048180)
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:40 +0x11c
    created by main.main
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:20 +0xf8
    
    goroutine 20 [chan send]:
    main.printNum(0x2, 0xc0420481e0, 0xc042048240)
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:40 +0x11c
    created by main.main
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:20 +0xf8
    
    goroutine 21 [chan send]:
    main.printNum(0x3, 0xc0420482a0, 0xc042048300)
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:40 +0x11c
    created by main.main
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:20 +0xf8
    
    goroutine 22 [chan send]:
    main.printNum(0x4, 0xc042048360, 0xc0420483c0)
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:40 +0x11c
    created by main.main
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:20 +0xf8
    
    goroutine 23 [chan send]:
    main.printNum(0x5, 0xc042048420, 0xc042048480)
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:40 +0x11c
    created by main.main
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:20 +0xf8
    
    goroutine 24 [chan send]:
    main.printNum(0x6, 0xc0420484e0, 0xc042048540)
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:40 +0x11c
    created by main.main
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:20 +0xf8
    
    goroutine 25 [chan send]:
    main.printNum(0x7, 0xc0420485a0, 0xc042048600)
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:40 +0x11c
    created by main.main
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:20 +0xf8
    
    goroutine 26 [chan send]:
    main.printNum(0x8, 0xc042048660, 0xc0420486c0)
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:40 +0x11c
    created by main.main
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:20 +0xf8
    
    goroutine 27 [chan send]:
    main.printNum(0x9, 0xc042048720, 0xc042048780)
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:40 +0x11c
    created by main.main
    	E:/GoProgram/awsomeproject/src/u2pppw/channel/testChannel.go:20 +0xf8
    
    Process finished with exit code 2

死锁问题,在第二个for循环执行完毕后，结构体实例中的信道channel都执行完了输入和输出的过程，而done信道只是执行了输入过程，输出（第四个for循环）还没有开始，此时再执行第三个for循环，向done信道内输入的话，造成死锁。可以在

func printNum(i int,w worker){
    	for{
    		//io操作会进行调度
    		fmt.Println(i,"got num:",<-w.channel)
    		w.done<-true
    	}
    }

内新开协程:

func printNum(i int, w worker) {
    	for {
    		//io操作会进行调度
    		fmt.Println(i, "got num:", <-w.channel)
    		go func() { w.done <- true }()
    	}
    }

输出结果:

5 got num: 102
    1 got num: 98
    4 got num: 101
    0 got num: 97
    3 got num: 100
    0 got num: 65
    1 got num: 66
    7 got num: 104
    8 got num: 105
    2 got num: 99
    9 got num: 106
    2 got num: 67
    5 got num: 70
    6 got num: 103
    4 got num: 69
    7 got num: 72
    6 got num: 71
    8 got num: 73
    3 got num: 68
    9 got num: 74

或者在两个任务之间接收done信道内数据:

package main
    
    import (
    	"fmt"
    )
    
    type worker struct {
    	channel chan int
    	done    chan bool
    }
    
    func main() {
    	var workers [10]worker
    
    	for i := 0; i < 10; i++ {
    		workers[i] = worker{
    			make(chan int),
    			make(chan bool),
    		}
    		go printNum(i, workers[i])
    	}
    	for i, w := range workers {
    		w.channel <- 'a' + i
    	}
    	for _, w := range workers {
    		<-w.done
    	}
    	for i, w := range workers {
    		w.channel <- 'A' + i
    	}
    
    	for _, w := range workers {
    		<-w.done
    	}
    	//保障协程运行完毕，主协程main运行结束之后，其他协程也全部结束
    	//time.Sleep(time.Duration(time.Millisecond))
    }
    func printNum(i int, w worker) {
    	for {
    		//io操作会进行调度
    		fmt.Println(i, "got num:", <-w.channel)
    		w.done <- true
    	}
    }

输出结果:

5 got num: 102
    8 got num: 105
    3 got num: 100
    0 got num: 97
    1 got num: 98
    2 got num: 99
    6 got num: 103
    4 got num: 101
    7 got num: 104
    9 got num: 106
    9 got num: 74
    4 got num: 69
    3 got num: 68
    6 got num: 71
    7 got num: 72
    8 got num: 73
    1 got num: 66
    2 got num: 67
    5 got num: 70
    0 got num: 65

使用waitGroup:

package main
    
    import (
    	"fmt"
    	"sync"
    )
    
    type worker struct {
    	channel chan int
    	wg *sync.WaitGroup
    }
    
    func main() {
    	var workers [10]worker
    
    	wg:=&sync.WaitGroup{}
    	wg.Add(20)
    	for i := 0; i < 10; i++ {
    		workers[i] = worker{
    			make(chan int),
    			wg,
    		}
    		go printNum(i, workers[i])
    	}
    
    	for i, w := range workers {
    		w.channel <- 'a' + i
    	}
    
    	for i, w := range workers {
    		w.channel <- 'A' + i
    	}
    	wg.Wait()
    
    }
    func printNum(i int, w worker) {
    	for in:=range w.channel{
    		fmt.Println(i, "got num:", in)
    		w.wg.Done()
    	}
    
    }

输出结果:

8 got num: 105
    0 got num: 97
    0 got num: 65
    3 got num: 100
    1 got num: 98
    1 got num: 66
    4 got num: 101
    6 got num: 103
    7 got num: 104
    5 got num: 102
    9 got num: 106
    2 got num: 99
    2 got num: 67
    9 got num: 74
    7 got num: 72
    6 got num: 71
    4 got num: 69
    3 got num: 68
    8 got num: 73
    5 got num: 70