在Golang中实现类似定时器的闹钟功能

huangapple
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英文:

Alarm like timer functionality in Golang

问题

有没有一种在Golang中设计一个在特定未来时间到期的定时器的方法？我的意思是一个在凌晨2点到期的定时器（假设当前时间是凌晨12点）。我知道一种方法是使用

  1.  timer(target_future_time - current_time)

但这似乎不是一个准确的方法（在考虑执行时间时可能不准确）。有人可以帮忙吗？

英文:

Is there any way for designing a timer that expires on a specific future time in Golang ? I mean a timer that expires on 2AM (let the current time be 12AM). I know one way is to use,

  1.  timer(target_future_time - current_time)

but doesn't seem to be an exact way of doing it (may not be accurate on considering the execution time). Can anyone help please?

答案1

得分: 2

在golang中，可能有两种方法创建ticker，就像下面的代码一样：

  1. package main
  3. import (
  4.     "fmt"
  5.     "time"
  6. )
  8. func main() {
  9.     //第一种实现方式 
  10.     ticker1 := time.NewTicker(1 * time.Second)
  11.     i := 1
  12.     for c := range ticker1.C {
  13.         i++
  14.         fmt.Println(c.Format("2006/01/02 15:04:05.999999999"))
  15.         if i > 5 {
  16.             ticker1.Stop()
  17.             break
  18.         }
  19.     }
  20.     fmt.Println(time.Now().Format("2006/01/02 15:04:05.999999999"), " 1 Finished.")
  22.     //第二种实现方式 
  23.     i = 1
  24.     ticker2 := time.AfterFunc(1*time.Second, func() {
  25.         i++
  26.         fmt.Println(time.Now().Format("2006/01/02 15:04:05.999999999"))
  27.     })
  29.     for {
  30.         select {
  31.         case <-ticker2.C:
  32.             fmt.Println("nsmei")
  33.         case <-time.After(3 * time.Second):
  34.             if i <= 5 {
  35.                 ticker2.Reset(1 * time.Second)
  36.                 continue
  37.             }
  38.             goto BRK
  39.         }
  40.     BRK:
  41.         ticker2.Stop()
  42.         break
  43.     }
  44.     fmt.Println(time.Now().Format("2006/01/02 15:04:05.999999999"), " 2 Finished.")
  45. }

输出结果：

  1. 2016/01/26 16:46:34.261248567
  2. 2016/01/26 16:46:35.256381743
  3. 2016/01/26 16:46:36.259717152
  4. 2016/01/26 16:46:37.260320837
  5. 2016/01/26 16:46:38.259312704
  6. 2016/01/26 16:46:38.259410752  1 Finished.
  7. 2016/01/26 16:46:39.260604274
  8. 2016/01/26 16:46:42.261091322
  9. 2016/01/26 16:46:45.263136257
  10. 2016/01/26 16:46:48.264193517
  11. 2016/01/26 16:46:51.265655137
  12. 2016/01/26 16:46:53.265722632  2 Finished.
  14. 根据执行结果，第一种方法比第二种方法更精确。
  16. 在你的情况下，你可以使用`time.Time.Sub()`来计算持续时间，并使用第二种方法执行一次，其余使用第一种方法。
  18. 希望这些对你有帮助！
  20. <details>
  21. <summary>英文:</summary>
  23. &lt;p&gt;In golang,maybe there are two way create ticker,just like the following:&lt;/p&gt;    
  24.     package main
  25.     
  26.     import (
  27.         &quot;fmt&quot;
  28.         &quot;time&quot;
  29.     )
  30.     
  31.     func main() {
  32.         //第一种实现方式 
  33.         ticker1 := time.NewTicker(1 * time.Second)
  34.         i := 1
  35.         for c := range ticker1.C {
  36.             i++
  37.             fmt.Println(c.Format(&quot;2006/01/02 15:04:05.999999999&quot;))
  38.             if i &gt; 5 {
  39.                 ticker1.Stop()
  40.                 break
  41.             }
  42.         }
  43.         fmt.Println(time.Now().Format(&quot;2006/01/02 15:04:05.999999999&quot;), &quot; 1 Finished.&quot;)
  44.     
  45.         //第二种实现方式 
  46.         i = 1
  47.         ticker2 := time.AfterFunc(1*time.Second, func() {
  48.             i++
  49.             fmt.Println(time.Now().Format(&quot;2006/01/02 15:04:05.999999999&quot;))
  50.         })
  51.     
  52.         for {
  53.             select {
  54.             case &lt;-ticker2.C:
  55.                 fmt.Println(&quot;nsmei&quot;)
  56.             case &lt;-time.After(3 * time.Second):
  57.                 if i &lt;= 5 {
  58.                     ticker2.Reset(1 * time.Second)
  59.                     continue
  60.                 }
  61.                 goto BRK
  62.             }
  63.         BRK:
  64.             ticker2.Stop()
  65.             break
  66.         }
  67.         fmt.Println(time.Now().Format(&quot;2006/01/02 15:04:05.999999999&quot;), &quot; 2 Finished.&quot;)
  68.     }
  69. Output:
  71.     2016/01/26 16:46:34.261248567
  72.     2016/01/26 16:46:35.256381743
  73.     2016/01/26 16:46:36.259717152
  74.     2016/01/26 16:46:37.260320837
  75.     2016/01/26 16:46:38.259312704
  76.     2016/01/26 16:46:38.259410752  1 Finished.
  77.     2016/01/26 16:46:39.260604274
  78.     2016/01/26 16:46:42.261091322
  79.     2016/01/26 16:46:45.263136257
  80.     2016/01/26 16:46:48.264193517
  81.     2016/01/26 16:46:51.265655137
  82.     2016/01/26 16:46:53.265722632  2 Finished.
  84. **According to the execution,the first is more precise than the second.**&lt;p&gt;In your case,you can use &lt;code&gt;time.Time.Sub()&lt;/code&gt; to calculate the duration,and execute once using the second method,the rest using the first method.&lt;/p&gt;
  85. &lt;p&gt;I hope these help you!&lt;/p&gt;
  87. </details>
  91. # 答案2
  92. **得分**: 0
  94. 以下是实现你的目的的代码。你只需要按照下面 main() 函数中所示的方式调用 ScheduleAlarm()。
  96. ```go
  97. package main
  99. import (
  100. 	"strings"
  101. 	"strconv"
  102. 	"fmt"
  103. 	"time"
  104. )
  106. // 表示时间的结构体。
  107. type Time struct {
  108. 	Hh int // 小时。
  109. 	Mm int // 分钟。
  110. 	Ss int // 秒。
  111. }
  113. func main() {
  114. 	/*
  115. 	按照下面所示的方式设置闹钟。
  116. 	时间必须以24小时制格式指定。
  117. 	同时，传递在闹钟触发后要调用的回调函数。
  118. 	*/
  119. 	alarm := ScheduleAlarm(Time{23, 28, 0}, func() {
  120. 		fmt.Println("收到闹钟")
  121. 	})
  123. 	// 做你的事情。
  124. 	for i := 0; i < 10; i++ {
  125. 		fmt.Println(i)
  126. 		time.Sleep(2 * time.Second)
  127. 	}
  129. 	// 不要忘记在需要阻塞的时候调用下面的代码。
  130. 	<-alarm
  131. }
  133. // 调用此函数来设置闹钟。在闹钟触发后，将调用回调函数。
  134. func ScheduleAlarm(alarmTime Time, callback func() ()) (endRecSignal chan string) {
  135. 	endRecSignal = make(chan string)
  136. 	go func() {
  137. 		timeSplice := strings.Split(time.Now().Format("15:04:05"), ":")
  138. 		hh, _ := strconv.Atoi(timeSplice[0])
  139. 		mm, _ := strconv.Atoi(timeSplice[1])
  140. 		ss, _ := strconv.Atoi(timeSplice[2])
  142. 		startAlarm := GetDiffSeconds(Time{hh, mm, ss}, alarmTime)
  144. 		// 设置闹钟。
  145. 		time.AfterFunc(time.Duration(startAlarm) * time.Second, func() {
  146. 			callback()
  147. 			endRecSignal <- "录音完成"
  148. 			close(endRecSignal)
  149. 		})
  150. 	}()
  151. 	return
  152. }
  154. func GetDiffSeconds(fromTime, toTime Time) int {
  155. 	fromSec := GetSeconds(fromTime)
  156. 	toSec := GetSeconds(toTime)
  157. 	diff := toSec - fromSec
  159. 	if diff < 0 {
  160. 		return diff + 24 * 60 * 60
  161. 	} else {
  162. 		return diff
  163. 	}
  164. }
  166. func GetSeconds(time Time) int {
  167. 	return time.Hh * 60 * 60 + time.Mm * 60 + time.Ss
  168. }

希望对你有所帮助。

英文:

The following code achieves your purpose. All you've to do is call ScheduleAlarm() in the manner shown in the main() function below.

  1. package main
  3. import (
  4. 	&quot;strings&quot;
  5. 	&quot;strconv&quot;
  6. 	&quot;fmt&quot;
  7. 	&quot;time&quot;
  8. )
  10. // A struct for representing time.
  11. type Time struct {
  12. 	Hh int // Hours.
  13. 	Mm int // Minutes.
  14. 	Ss int // Seconds.
  15. }
  17. func main() {
  18. 	/*
  19. 	Set the alarm as shown below.
  20. 	Time must be specified in 24 hour clock format.
  21. 	Also, pass the callback to be called after the alarm is triggered.
  22. 	*/
  23. 	alarm := ScheduleAlarm(Time{23, 28, 0}, func() {
  24. 		fmt.Println(&quot;alarm received&quot;)
  25. 	})
  27. 	// Do your stuff.
  28. 	for i := 0; i &lt; 10; i++ {
  29. 		fmt.Println(i)
  30. 		time.Sleep(2 * time.Second)
  31. 	}
  33. 	// Don&#39;t forget to call the below line whenever you want to block.
  34. 	&lt;-alarm
  35. }
  37. // Call this function to schedule the alarm. The callback will be called after the alarm is triggered.
  38. func ScheduleAlarm(alarmTime Time, callback func() ()) (endRecSignal chan string) {
  39. 	endRecSignal = make(chan string)
  40. 	go func() {
  41. 		timeSplice := strings.Split(time.Now().Format(&quot;15:04:05&quot;), &quot;:&quot;)
  42. 		hh, _ := strconv.Atoi(timeSplice[0])
  43. 		mm, _ := strconv.Atoi(timeSplice[1])
  44. 		ss, _ := strconv.Atoi(timeSplice[2])
  46. 		startAlarm := GetDiffSeconds(Time{hh, mm, ss}, alarmTime)
  48. 		// Setting alarm.
  49. 		time.AfterFunc(time.Duration(startAlarm) * time.Second, func() {
  50. 			callback()
  51. 			endRecSignal &lt;- &quot;finished recording&quot;
  52. 			close(endRecSignal)
  53. 		})
  54. 	}()
  55. 	return
  56. }
  58. func GetDiffSeconds(fromTime, toTime Time) int {
  59. 	fromSec := GetSeconds(fromTime)
  60. 	toSec := GetSeconds(toTime)
  61. 	diff := toSec - fromSec
  63. 	if diff &lt; 0 {
  64. 		return diff + 24 * 60 * 60
  65. 	} else {
  66. 		return diff
  67. 	}
  68. }
  70. func GetSeconds(time Time) int {
  71. 	return time.Hh * 60 * 60 + time.Mm * 60 + time.Ss
  72. }

Hope this helps.

huangapple
  • 本文由 发表于 2016年1月26日 15:51:16
  • 转载请务必保留本文链接：https://go.coder-hub.com/35009070.html
  • go
  • timer
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