VB.NET并行与分布式编程(6)-线程与内核同步[14]

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我是靠谱客的博主善良眼睛，最近开发中收集的这篇文章主要介绍VB.NET并行与分布式编程(6)-线程与内核同步[14]，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

Imports System
Imports System.Threading
Imports System.Diagnostics
Imports System.Diagnostics.ThreadState
Module Module1
Sub Main()
Dim mythread1 As Thread
Dim mythread2 As Thread
Dim mythread3 As Thread
'创建线程对象
mythread1 = New Thread(AddressOf mythreadrun)
mythread2 = New Thread(AddressOf mythreadrun)
mythread3 = New Thread(AddressOf mythreadrun)
mythread1.Name = "thread_1"
mythread2.Name = "thread_2"
mythread3.Name = "thread_3"
'设置线程是否允许动态优先级
Console.WriteLine(Now.ToLongTimeString & "线程对象创建完毕,开始执行线程")
Dim myprocess As Process = Process.GetCurrentProcess()
Console.WriteLine("进程名称:" & myprocess.ProcessName)
'执行线程
mythread1.Start(myprocess)
mythread2.Start(myprocess)
mythread3.Start(myprocess)
'等待线程完成
mythread1.Join()
mythread2.Join()
mythread3.Join()
'线程执行完毕
Console.WriteLine(Now.ToLongTimeString & "线程执行完毕!")
End Sub
Public Sub mythreadrun(ByVal myprocess As Object)
Dim mynum As Double
Static Dim mymonitorobj As New Object
Static Dim jg As Double = 100
Try
For mynum = 1 To 10
'隐式获取监视器
SyncLock mymonitorobj
jg -= mynum
Console.WriteLine(Thread.CurrentThread.Name & "==>" & Now.ToLongTimeString & "=>" & (jg + mynum) & "-" & mynum & "，计算结果为：" & jg)
End SyncLock
Thread.Sleep(0)
Next
Catch
Console.WriteLine(Thread.CurrentThread.Name & "
" & Now.ToLongTimeString & "线程异常终止!")
'终止线程
Thread.CurrentThread.Abort()
Finally
Console.WriteLine(Thread.CurrentThread.Name & "优先级:
" & Thread.CurrentThread.Priority.ToString)
Console.WriteLine(Thread.CurrentThread.Name & "
" & Now.ToLongTimeString & "线程运行完毕!")
End Try
End Sub
End Module

上面的代码我们使用监视器

1)监视器的定义

Static Dim mymonitorobj As New Object
2)使用 SyncLock关键字隐式获取监视器,制造互斥的临界域
                SyncLock mymonitorobj
                    jg -= mynum
                    Console.WriteLine(Thread.CurrentThread.Name & "==>" & Now.ToLongTimeString & "=>" & (jg + mynum) & "-" & mynum & "，计算结果为：" & jg)
                End SyncLock
此外，我们可以直接使用Monitor.enter方法和Monitor.exit方法

Monitor.Enter(mymonitorobj)
                jg -= mynum
                Console.WriteLine(Thread.CurrentThread.Name & "==>" & Now.ToLongTimeString & "=>" & (jg + mynum) & "-" & mynum & "，计算结果为：" & jg)
                Monitor.Exit(mymonitorobj)

代码如下

Imports System
Imports System.Threading
Imports System.Diagnostics
Imports System.Diagnostics.ThreadState
Module Module1
Sub Main()
Dim mythread1 As Thread
Dim mythread2 As Thread
Dim mythread3 As Thread
'创建线程对象
mythread1 = New Thread(AddressOf mythreadrun)
mythread2 = New Thread(AddressOf mythreadrun)
mythread3 = New Thread(AddressOf mythreadrun)
mythread1.Name = "thread_1"
mythread2.Name = "thread_2"
mythread3.Name = "thread_3"
'设置线程是否允许动态优先级
Console.WriteLine(Now.ToLongTimeString & "线程对象创建完毕,开始执行线程")
Dim myprocess As Process = Process.GetCurrentProcess()
Console.WriteLine("进程名称:" & myprocess.ProcessName)
'执行线程
mythread1.Start(myprocess)
mythread2.Start(myprocess)
mythread3.Start(myprocess)
'等待线程完成
mythread1.Join()
mythread2.Join()
mythread3.Join()
'线程执行完毕
Console.WriteLine(Now.ToLongTimeString & "线程执行完毕!")
End Sub
Public Sub mythreadrun(ByVal myprocess As Object)
Dim mynum As Double
Static Dim mymonitorobj As New Object
Static Dim jg As Double = 100
Try
For mynum = 1 To 10
'使用 监视器
Monitor.Enter(mymonitorobj)
jg -= mynum
Console.WriteLine(Thread.CurrentThread.Name & "==>" & Now.ToLongTimeString & "=>" & (jg + mynum) & "-" & mynum & "，计算结果为：" & jg)
Monitor.Exit(mymonitorobj)
Thread.Sleep(0)
Next
Catch
Console.WriteLine(Thread.CurrentThread.Name & "
" & Now.ToLongTimeString & "线程异常终止!")
'终止线程
Thread.CurrentThread.Abort()
Finally
Console.WriteLine(Thread.CurrentThread.Name & "优先级:
" & Thread.CurrentThread.Priority.ToString)
Console.WriteLine(Thread.CurrentThread.Name & "
" & Now.ToLongTimeString & "线程运行完毕!")
End Try
End Sub
End Module

上述方法将阻塞等待线程，我们可以使用TryEnter来避免阻塞，在等待的同时做一些其它工作

'使用监视器，同时为避免阻塞，在等待的过程中做其它工作
                While Not Monitor.TryEnter(mymonitorobj)
                    Console.WriteLine(Thread.CurrentThread.Name & "正在等待.....")
                End While
                Try
                    jg -= mynum
                    Console.WriteLine(Thread.CurrentThread.Name & "==>" & Now.ToLongTimeString & "=>" & (jg + mynum) & "-" & mynum & "，计算结果为：" & jg)
                Finally
                    Monitor.Exit(mymonitorobj)
                End Try

Thread.Sleep(0)

完整代码如下:

Imports System
Imports System.Threading
Imports System.Diagnostics
Imports System.Diagnostics.ThreadState
Module Module1
Sub Main()
Dim mythread1 As Thread
Dim mythread2 As Thread
Dim mythread3 As Thread
'创建线程对象
mythread1 = New Thread(AddressOf mythreadrun)
mythread2 = New Thread(AddressOf mythreadrun)
mythread3 = New Thread(AddressOf mythreadrun)
mythread1.Name = "thread_1"
mythread2.Name = "thread_2"
mythread3.Name = "thread_3"
'设置线程是否允许动态优先级
Console.WriteLine(Now.ToLongTimeString & "线程对象创建完毕,开始执行线程")
Dim myprocess As Process = Process.GetCurrentProcess()
Console.WriteLine("进程名称:" & myprocess.ProcessName)
'执行线程
mythread1.Start(myprocess)
mythread2.Start(myprocess)
mythread3.Start(myprocess)
'等待线程完成
mythread1.Join()
mythread2.Join()
mythread3.Join()
'线程执行完毕
Console.WriteLine(Now.ToLongTimeString & "线程执行完毕!")
End Sub
Public Sub mythreadrun(ByVal myprocess As Object)
Dim mynum As Double
Static Dim mymonitorobj As New Object
Static Dim jg As Double = 100
Try
For mynum = 1 To 10
'使用 监视器，同时为避免阻塞，在等待的过程中做其它工作
While Not Monitor.TryEnter(mymonitorobj)
Console.WriteLine(Thread.CurrentThread.Name & "正在等待.....")
End While
Try
jg -= mynum
Console.WriteLine(Thread.CurrentThread.Name & "==>" & Now.ToLongTimeString & "=>" & (jg + mynum) & "-" & mynum & "，计算结果为：" & jg)
Finally
Monitor.Exit(mymonitorobj)
End Try
Thread.Sleep(0)
Next
Catch
Console.WriteLine(Thread.CurrentThread.Name & "
" & Now.ToLongTimeString & "线程异常终止!")
'终止线程
Thread.CurrentThread.Abort()
Finally
Console.WriteLine(Thread.CurrentThread.Name & "优先级:
" & Thread.CurrentThread.Priority.ToString)
Console.WriteLine(Thread.CurrentThread.Name & "
" & Now.ToLongTimeString & "线程运行完毕!")
End Try
End Sub
End Module

效果如下: