VB.NET并行与分布式编程(6)-线程与内核同步[14]

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: