PowerShell的管道添加换行 [英] PowerShell's pipe adds linefeed
问题描述
我正在尝试将字符串传递到程序的STDIN 中,而没有任何尾随的换行符(除非该字符串本身实际上以换行符结尾).我尝试使用谷歌搜索功能,但只发现有人尝试打印到控制台而没有尾随换行符,在这种情况下,Write-Host
带有参数-NoNewLine
.但是,要将其通过管道传输到另一个程序,我需要Write-Output
或类似的没有这样的参数的文件.现在看来Write-Output
甚至不是问题:
I'm trying to pipe a string into a program's STDIN without any trailing linefeeds (unless that string itself actually ends in a linefeed). I tried googling around, but I only found people trying to print to the console without a trailing linefeed, in which case Write-Host
takes a parameter -NoNewLine
. However, to pipe it on to another program, I need Write-Output
or similar which doesn't have such a parameter. Now it seems like Write-Output
isn't even the problem:
Z:\> (Write-Output "abc").Length
3
但是,一旦我将其通过管道传送到另一个程序并在其中读取字符串,我就会获得一个额外的换行符.例如,我尝试了以下Ruby代码段:
But as soon as I pipe it to another program and read the string there, I get an additional linefeed. For instance, I tried this Ruby snippet:
Z:\> Write-Output "abc" | ruby -e "p ARGF.read"
"abc\n"
我检查了收到的实际字符串是abc\n
.在其他几种语言(至少是C#,Java和Python)中也会发生同样的情况,因此我认为这是PowerShell的问题,而不是使用阅读语言.
I checked that the actual string received is abc\n
. The same happens in several other languages (at least C#, Java and Python), so I believe it's an issue with PowerShell, not the language doing the reading.
作为进一步的测试,我用另一个Ruby脚本替换了Write-Output
本身:
As a further test, I replaced Write-Output
itself with another Ruby script:
Z:\> ruby -e "$> << 'abc'"
abcZ:\>
(也就是说,脚本的STDOUT上绝对没有\n
.)
(That is, there is definitely no \n
on the script's STDOUT.)
但是,当我再次将其传送到另一个脚本中时:
But again, when I pipe it into another script:
Z:\> ruby -e "$> << 'abc'" | ruby -e "p ARGF.read"
"abc\n"
我相当确信这是添加换行符的管道.我该如何避免呢?我实际上希望能够控制输入是否以换行结尾(通过将其包含在输入中或将其省略).
I'm fairly convinced that it's the pipe which adds the linefeed. How do I avoid that? I actually want to be able to control whether the input ends in a linefeed or not (by including it in the input or omitting it).
(作为参考,我还测试了已经包含尾随换行符的字符串,在这种情况下,管道不添加了另一个,所以我想它只是确保尾随换行符.)
(For reference, I also tested strings which already contain a trailing linefeed, and in that case the pipe doesn't add another one, so I guess it just ensures a trailing linefeed.)
我最初在PowerShell v3中遇到此问题,但现在使用v5,但仍然存在相同的问题.
I originally encountered this in PowerShell v3, but I'm now using v5 and still have the same issue.
推荐答案
简介
这是我的Invoke-RawPipeline
函数(从此要点获取最新版本)..
Introduction
Here is my Invoke-RawPipeline
function (get latest version from this Gist).
使用它在进程的标准输出和标准输入流之间传递二进制数据.它可以从文件/管道读取输入流,并将生成的输出流保存到文件.
Use it to pipe binary data between processes' Standard Output and Standard Input streams. It can read input stream from file/pipeline and save resulting output stream to file.
它需要 PsAsync模块,才能在多个进程中启动和传递数据.
It requires PsAsync module to be able to launch and pipe data in multiple processes.
万一出现问题,请使用-Verbose
开关查看调试输出.
In case of issues use -Verbose
switch to see debug output.
- 批次:
findstr.exe /C:"Warning" /I C:\Windows\WindowsUpdate.log > C:\WU_Warnings.txt
- PowerShell:
Invoke-RawPipeline -Command @{Path = 'findstr.exe' ; Arguments = '/C:"Warning" /I C:\Windows\WindowsUpdate.log'} -OutFile 'C:\WU_Warnings.txt'
- Batch:
findstr.exe /C:"Warning" /I C:\Windows\WindowsUpdate.log > C:\WU_Warnings.txt
- PowerShell:
Invoke-RawPipeline -Command @{Path = 'findstr.exe' ; Arguments = '/C:"Warning" /I C:\Windows\WindowsUpdate.log'} -OutFile 'C:\WU_Warnings.txt'
- 批次:
svnadmin load < C:\RepoDumps\MyRepo.dump
- PowerShell:
Invoke-RawPipeline -InFile 'C:\RepoDumps\MyRepo.dump' -Command @{Path = 'svnadmin.exe' ; Arguments = 'load'}
- Batch:
svnadmin load < C:\RepoDumps\MyRepo.dump
- PowerShell:
Invoke-RawPipeline -InFile 'C:\RepoDumps\MyRepo.dump' -Command @{Path = 'svnadmin.exe' ; Arguments = 'load'}
- 批次:
echo TestString | find /I "test" > C:\SearchResult.log
- PowerShell:
'TestString' | Invoke-RawPipeline -Command @{Path = 'find.exe' ; Arguments = '/I "test"'} -OutFile 'C:\SearchResult.log'
- Batch:
echo TestString | find /I "test" > C:\SearchResult.log
- PowerShell:
'TestString' | Invoke-RawPipeline -Command @{Path = 'find.exe' ; Arguments = '/I "test"'} -OutFile 'C:\SearchResult.log'
- 批次:
ipconfig | findstr /C:"IPv4 Address" /I
- PowerShell:
Invoke-RawPipeline -Command @{Path = 'ipconfig'}, @{Path = 'findstr' ; Arguments = '/C:"IPv4 Address" /I'} -RawData
- Batch:
ipconfig | findstr /C:"IPv4 Address" /I
- PowerShell:
Invoke-RawPipeline -Command @{Path = 'ipconfig'}, @{Path = 'findstr' ; Arguments = '/C:"IPv4 Address" /I'} -RawData
<#
.Synopsis
Pipe binary data between processes' Standard Output and Standard Input streams.
Can read input stream from file and save resulting output stream to file.
.Description
Pipe binary data between processes' Standard Output and Standard Input streams.
Can read input stream from file/pipeline and save resulting output stream to file.
Requires PsAsync module: http://psasync.codeplex.com
.Notes
Author: beatcracker (https://beatcracker.wordpress.com, https://github.com/beatcracker)
License: Microsoft Public License (http://opensource.org/licenses/MS-PL)
.Component
Requires PsAsync module: http://psasync.codeplex.com
.Parameter Command
An array of hashtables, each containing Command Name, Working Directory and Arguments
.Parameter InFile
This parameter is optional.
A string representing path to file, to read input stream from.
.Parameter OutFile
This parameter is optional.
A string representing path to file, to save resulting output stream to.
.Parameter Append
This parameter is optional. Default is false.
A switch controlling wheither ovewrite or append output file if it already exists. Default is to overwrite.
.Parameter IoTimeout
This parameter is optional. Default is 0.
A number of seconds to wait if Input/Output streams are blocked. Default is to wait indefinetely.
.Parameter ProcessTimeout
This parameter is optional. Default is 0.
A number of seconds to wait for process to exit after finishing all pipeline operations. Default is to wait indefinetely.
Details: https://msdn.microsoft.com/en-us/library/ty0d8k56.aspx
.Parameter BufferSize
This parameter is optional. Default is 4096.
Size of buffer in bytes for read\write operations. Supports standard Powershell multipliers: KB, MB, GB, TB, and PB.
Total number of buffers is: Command.Count * 2 + InFile + OutFile.
.Parameter ForceGC
This parameter is optional.
A switch, that if specified will force .Net garbage collection.
Use to immediately release memory on function exit, if large buffer size was used.
.Parameter RawData
This parameter is optional.
By default function returns object with StdOut/StdErr streams and process' exit codes.
If this switch is specified, function will return raw Standard Output stream.
.Example
Invoke-RawPipeline -Command @{Path = 'findstr.exe' ; Arguments = '/C:"Warning" /I C:\Windows\WindowsUpdate.log'} -OutFile 'C:\WU_Warnings.txt'
Batch analog: findstr.exe /C:"Warning" /I C:\Windows\WindowsUpdate.log' > C:\WU_Warnings.txt
.Example
Invoke-RawPipeline -Command @{Path = 'findstr.exe' ; WorkingDirectory = 'C:\Windows' ; Arguments = '/C:"Warning" /I .\WindowsUpdate.log'} -RawData
Batch analog: cd /D C:\Windows && findstr.exe /C:"Warning" /I .\WindowsUpdate.log
.Example
'TestString' | Invoke-RawPipeline -Command @{Path = 'find.exe' ; Arguments = '/I "test"'} -OutFile 'C:\SearchResult.log'
Batch analog: echo TestString | find /I "test" > C:\SearchResult.log
.Example
Invoke-RawPipeline -Command @{Path = 'ipconfig'}, @{Path = 'findstr' ; Arguments = '/C:"IPv4 Address" /I'} -RawData
Batch analog: ipconfig | findstr /C:"IPv4 Address" /I
.Example
Invoke-RawPipeline -InFile 'C:\RepoDumps\Repo.svn' -Command @{Path = 'svnadmin.exe' ; Arguments = 'load'}
Batch analog: svnadmin load < C:\RepoDumps\MyRepo.dump
#>
function Invoke-RawPipeline
{
[CmdletBinding()]
Param
(
[Parameter(ValueFromPipeline = $true)]
[ValidateNotNullOrEmpty()]
[ValidateScript({
if($_.psobject.Methods.Match.('ToString'))
{
$true
}
else
{
throw 'Can''t convert pipeline object to string!'
}
})]
$InVariable,
[Parameter(ValueFromPipelineByPropertyName = $true)]
[ValidateScript({
$_ | ForEach-Object {
$Path = $_.Path
$WorkingDirectory = $_.WorkingDirectory
if(!(Get-Command -Name $Path -CommandType Application -ErrorAction SilentlyContinue))
{
throw "Command not found: $Path"
}
if($WorkingDirectory)
{
if(!(Test-Path -LiteralPath $WorkingDirectory -PathType Container -ErrorAction SilentlyContinue))
{
throw "Working directory not found: $WorkingDirectory"
}
}
}
$true
})]
[ValidateNotNullOrEmpty()]
[array]$Command,
[Parameter(ValueFromPipelineByPropertyName = $true)]
[ValidateScript({
if(!(Test-Path -LiteralPath $_))
{
throw "File not found: $_"
}
$true
})]
[ValidateNotNullOrEmpty()]
[string]$InFile,
[Parameter(ValueFromPipelineByPropertyName = $true)]
[ValidateScript({
if(!(Test-Path -LiteralPath (Split-Path $_)))
{
throw "Folder not found: $_"
}
$true
})]
[ValidateNotNullOrEmpty()]
[string]$OutFile,
[Parameter(ValueFromPipelineByPropertyName = $true)]
[switch]$Append,
[Parameter(ValueFromPipelineByPropertyName = $true)]
[ValidateRange(0, 2147483)]
[int]$IoTimeout = 0,
[Parameter(ValueFromPipelineByPropertyName = $true)]
[ValidateRange(0, 2147483)]
[int]$ProcessTimeout = 0,
[Parameter(ValueFromPipelineByPropertyName = $true)]
[long]$BufferSize = 4096,
[Parameter(ValueFromPipelineByPropertyName = $true)]
[switch]$RawData,
[Parameter(ValueFromPipelineByPropertyName = $true)]
[switch]$ForceGC
)
Begin
{
$Modules = @{PsAsync = 'http://psasync.codeplex.com'}
'Loading modules:', ($Modules | Format-Table -HideTableHeaders -AutoSize | Out-String) | Write-Verbose
foreach($module in $Modules.GetEnumerator())
{
if(!(Get-Module -Name $module.Key))
{
Try
{
Import-Module -Name $module.Key -ErrorAction Stop
}
Catch
{
throw "$($module.Key) module not available. Get it here: $($module.Value)"
}
}
}
function New-ConsoleProcess
{
Param
(
[string]$Path,
[string]$Arguments,
[string]$WorkingDirectory,
[switch]$CreateNoWindow = $true,
[switch]$RedirectStdIn = $true,
[switch]$RedirectStdOut = $true,
[switch]$RedirectStdErr = $true
)
if(!$WorkingDirectory)
{
if(!$script:MyInvocation.MyCommand.Path)
{
$WorkingDirectory = [System.AppDomain]::CurrentDomain.BaseDirectory
}
else
{
$WorkingDirectory = Split-Path $script:MyInvocation.MyCommand.Path
}
}
Try
{
$ps = New-Object -TypeName System.Diagnostics.Process -ErrorAction Stop
$ps.StartInfo.Filename = $Path
$ps.StartInfo.Arguments = $Arguments
$ps.StartInfo.UseShellExecute = $false
$ps.StartInfo.RedirectStandardInput = $RedirectStdIn
$ps.StartInfo.RedirectStandardOutput = $RedirectStdOut
$ps.StartInfo.RedirectStandardError = $RedirectStdErr
$ps.StartInfo.CreateNoWindow = $CreateNoWindow
$ps.StartInfo.WorkingDirectory = $WorkingDirectory
}
Catch
{
throw $_
}
return $ps
}
function Invoke-GarbageCollection
{
[gc]::Collect()
[gc]::WaitForPendingFinalizers()
}
$CleanUp = {
$IoWorkers + $StdErrWorkers |
ForEach-Object {
$_.Src, $_.Dst |
ForEach-Object {
if(!($_ -is [System.Diagnostics.Process]))
{
Try
{
$_.Close()
}
Catch
{
Write-Error "Failed to close $_"
}
$_.Dispose()
}
}
}
}
$PumpData = {
Param
(
[hashtable]$Cfg
)
# Fail hard, we don't want stuck threads
$Private:ErrorActionPreference = 'Stop'
$Src = $Cfg.Src
$SrcEndpoint = $Cfg.SrcEndpoint
$Dst = $Cfg.Dst
$DstEndpoint = $Cfg.DstEndpoint
$BufferSize = $Cfg.BufferSize
$SyncHash = $Cfg.SyncHash
$RunspaceId = $Cfg.Id
# Setup Input and Output streams
if($Src -is [System.Diagnostics.Process])
{
switch ($SrcEndpoint)
{
'StdOut' {$InStream = $Src.StandardOutput.BaseStream}
'StdIn' {$InStream = $Src.StandardInput.BaseStream}
'StdErr' {$InStream = $Src.StandardError.BaseStream}
default {throw "Not valid source endpoint: $_"}
}
}
else
{
$InStream = $Src
}
if($Dst -is [System.Diagnostics.Process])
{
switch ($DstEndpoint)
{
'StdOut' {$OutStream = $Dst.StandardOutput.BaseStream}
'StdIn' {$OutStream = $Dst.StandardInput.BaseStream}
'StdErr' {$OutStream = $Dst.StandardError.BaseStream}
default {throw "Not valid destination endpoint: $_"}
}
}
else
{
$OutStream = $Dst
}
$InStream | Out-String | ForEach-Object {$SyncHash.$RunspaceId.Status += "InStream: $_"}
$OutStream | Out-String | ForEach-Object {$SyncHash.$RunspaceId.Status += "OutStream: $_"}
# Main data copy loop
$Buffer = New-Object -TypeName byte[] $BufferSize
$BytesThru = 0
Try
{
Do
{
$SyncHash.$RunspaceId.IoStartTime = [DateTime]::UtcNow.Ticks
$ReadCount = $InStream.Read($Buffer, 0, $Buffer.Length)
$OutStream.Write($Buffer, 0, $ReadCount)
$OutStream.Flush()
$BytesThru += $ReadCount
}
While($readCount -gt 0)
}
Catch
{
$SyncHash.$RunspaceId.Status += $_
}
Finally
{
$OutStream.Close()
$InStream.Close()
}
}
}
Process
{
$PsCommand = @()
if($Command.Length)
{
Write-Verbose 'Creating new process objects'
$i = 0
foreach($cmd in $Command.GetEnumerator())
{
$PsCommand += New-ConsoleProcess @cmd
$i++
}
}
Write-Verbose 'Building I\O pipeline'
$PipeLine = @()
if($InVariable)
{
[Byte[]]$InVarBytes = [Text.Encoding]::UTF8.GetBytes($InVariable.ToString())
$PipeLine += New-Object -TypeName System.IO.MemoryStream -ArgumentList $BufferSize -ErrorAction Stop
$PipeLine[-1].Write($InVarBytes, 0, $InVarBytes.Length)
[Void]$PipeLine[-1].Seek(0, 'Begin')
}
elseif($InFile)
{
$PipeLine += New-Object -TypeName System.IO.FileStream -ArgumentList ($InFile, [IO.FileMode]::Open) -ErrorAction Stop
if($PsCommand.Length)
{
$PsCommand[0].StartInfo.RedirectStandardInput = $true
}
}
else
{
if($PsCommand.Length)
{
$PsCommand[0].StartInfo.RedirectStandardInput = $false
}
}
$PipeLine += $PsCommand
if($OutFile)
{
if($PsCommand.Length)
{
$PsCommand[-1].StartInfo.RedirectStandardOutput = $true
}
if($Append)
{
$FileMode = [System.IO.FileMode]::Append
}
else
{
$FileMode = [System.IO.FileMode]::Create
}
$PipeLine += New-Object -TypeName System.IO.FileStream -ArgumentList ($OutFile, $FileMode, [System.IO.FileAccess]::Write) -ErrorAction Stop
}
else
{
if($PsCommand.Length)
{
$PipeLine += New-Object -TypeName System.IO.MemoryStream -ArgumentList $BufferSize -ErrorAction Stop
}
}
Write-Verbose 'Creating I\O threads'
$IoWorkers = @()
for($i=0 ; $i -lt ($PipeLine.Length-1) ; $i++)
{
$SrcEndpoint = $DstEndpoint = $null
if($PipeLine[$i] -is [System.Diagnostics.Process])
{
$SrcEndpoint = 'StdOut'
}
if($PipeLine[$i+1] -is [System.Diagnostics.Process])
{
$DstEndpoint = 'StdIn'
}
$IoWorkers += @{
Src = $PipeLine[$i]
SrcEndpoint = $SrcEndpoint
Dst = $PipeLine[$i+1]
DstEndpoint = $DstEndpoint
}
}
Write-Verbose "Created $($IoWorkers.Length) I\O worker objects"
Write-Verbose 'Creating StdErr readers'
$StdErrWorkers = @()
for($i=0 ; $i -lt $PsCommand.Length ; $i++)
{
$StdErrWorkers += @{
Src = $PsCommand[$i]
SrcEndpoint = 'StdErr'
Dst = New-Object -TypeName System.IO.MemoryStream -ArgumentList $BufferSize -ErrorAction Stop
}
}
Write-Verbose "Created $($StdErrWorkers.Length) StdErr reader objects"
Write-Verbose 'Starting processes'
$PsCommand |
ForEach-Object {
$ps = $_
Try
{
[void]$ps.Start()
}
Catch
{
Write-Error "Failed to start process: $($ps.StartInfo.FileName)"
Write-Verbose "Can't launch process, killing and disposing all"
if($PsCommand)
{
$PsCommand |
ForEach-Object {
Try{$_.Kill()}Catch{} # Can't do much if kill fails...
$_.Dispose()
}
}
Write-Verbose 'Closing and disposing I\O streams'
. $CleanUp
}
Write-Verbose "Started new process: Name=$($ps.Name), Id=$($ps.Id)"
}
$WorkersCount = $IoWorkers.Length + $StdErrWorkers.Length
Write-Verbose 'Creating sync hashtable'
$sync = @{}
for($i=0 ; $i -lt $WorkersCount ; $i++)
{
$sync += @{$i = @{IoStartTime = $nul ; Status = $null}}
}
$SyncHash = [hashtable]::Synchronized($sync)
Write-Verbose 'Creating runspace pool'
$RunspacePool = Get-RunspacePool $WorkersCount
Write-Verbose 'Loading workers on the runspace pool'
$AsyncPipelines = @()
$i = 0
$IoWorkers + $StdErrWorkers |
ForEach-Object {
$Param = @{
BufferSize = $BufferSize
Id = $i
SyncHash = $SyncHash
} + $_
$AsyncPipelines += Invoke-Async -RunspacePool $RunspacePool -ScriptBlock $PumpData -Parameters $Param
$i++
Write-Verbose 'Started working thread'
$Param | Format-Table -HideTableHeaders -AutoSize | Out-String | Write-Debug
}
Write-Verbose 'Waiting for I\O to complete...'
if($IoTimeout){Write-Verbose "Timeout is $IoTimeout seconds"}
Do
{
# Check for pipelines with errors
[array]$FailedPipelines = Receive-AsyncStatus -Pipelines $AsyncPipelines | Where-Object {$_.Completed -and $_.Error}
if($FailedPipelines)
{
"$($FailedPipelines.Length) pipeline(s) failed!",
($FailedPipelines | Select-Object -ExpandProperty Error | Format-Table -AutoSize | Out-String) | Write-Debug
}
if($IoTimeout)
{
# Compare I\O start time of thread with current time
[array]$LockedReaders = $SyncHash.Keys | Where-Object {[TimeSpan]::FromTicks([DateTime]::UtcNow.Ticks - $SyncHash.$_.IoStartTime).TotalSeconds -gt $IoTimeout}
if($LockedReaders)
{
# Yikes, someone is stuck
"$($LockedReaders.Length) I\O operations reached timeout!" | Write-Verbose
$SyncHash.GetEnumerator() | ForEach-Object {"$($_.Key) = $($_.Value.Status)"} | Sort-Object | Out-String | Write-Debug
$PsCommand | ForEach-Object {
Write-Verbose "Killing process: Name=$($_.Name), Id=$($_.Id)"
Try
{
$_.Kill()
}
Catch
{
Write-Error 'Failed to kill process!'
}
}
break
}
}
Start-Sleep 1
}
While(Receive-AsyncStatus -Pipelines $AsyncPipelines | Where-Object {!$_.Completed}) # Loop until all pipelines are finished
Write-Verbose 'Waiting for all pipelines to finish...'
$IoStats = Receive-AsyncResults -Pipelines $AsyncPipelines
Write-Verbose 'All pipelines are finished'
Write-Verbose 'Collecting StdErr for all processes'
$PipeStdErr = $StdErrWorkers |
ForEach-Object {
$Encoding = $_.Src.StartInfo.StandardOutputEncoding
if(!$Encoding)
{
$Encoding = [System.Text.Encoding]::Default
}
@{
FileName = $_.Src.StartInfo.FileName
StdErr = $Encoding.GetString($_.Dst.ToArray())
ExitCode = $_.Src.ExitCode
}
} |
Select-Object @{Name = 'FileName' ; Expression = {$_.FileName}},
@{Name = 'StdErr' ; Expression = {$_.StdErr}},
@{Name = 'ExitCode' ; Expression = {$_.ExitCode}}
if($IoWorkers[-1].Dst -is [System.IO.MemoryStream])
{
Write-Verbose 'Collecting final pipeline output'
if($IoWorkers[-1].Src -is [System.Diagnostics.Process])
{
$Encoding = $IoWorkers[-1].Src.StartInfo.StandardOutputEncoding
}
if(!$Encoding)
{
$Encoding = [System.Text.Encoding]::Default
}
$PipeResult = $Encoding.GetString($IoWorkers[-1].Dst.ToArray())
}
Write-Verbose 'Closing and disposing I\O streams'
. $CleanUp
$PsCommand |
ForEach-Object {
$_.Refresh()
if(!$_.HasExited)
{
Write-Verbose "Process is still active: Name=$($_.Name), Id=$($_.Id)"
if(!$ProcessTimeout)
{
$ProcessTimeout = -1
}
else
{
$WaitForExitProcessTimeout = $ProcessTimeout * 1000
}
Write-Verbose "Waiting for process to exit (Process Timeout = $ProcessTimeout)"
if(!$_.WaitForExit($WaitForExitProcessTimeout))
{
Try
{
Write-Verbose 'Trying to kill it'
$_.Kill()
}
Catch
{
Write-Error "Failed to kill process $_"
}
}
}
Write-Verbose "Disposing process object: Name=$($_.StartInfo.FileName)"
$_.Dispose()
}
Write-Verbose 'Disposing runspace pool'
# http://stackoverflow.com/questions/21454252/how-to-cleanup-resources-in-a-dll-when-powershell-ise-exits-like-new-pssession
$RunspacePool.Dispose()
if($ForceGC)
{
Write-Verbose 'Forcing garbage collection'
Invoke-GarbageCollection
}
if(!$RawData)
{
New-Object -TypeName psobject -Property @{Result = $PipeResult ; Status = $PipeStdErr}
}
else
{
$PipeResult
}
}
}
这篇关于PowerShell的管道添加换行的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!