为了解决这个问题，我使用setx和set改变了环境变量，然后重新启动explorer.exe的所有实例。这样，随后启动的任何进程都将拥有新的环境变量。

我的批处理脚本这样做:

setx /M ENVVAR "NEWVALUE"
set ENVVAR="NEWVALUE"

taskkill /f /IM explorer.exe
start explorer.exe >nul
exit

这种方法的问题是当前打开的所有资源管理器窗口都将被关闭，这可能是一个坏主意-但请参阅Kev的帖子来了解为什么这是必要的

我只是想说，那些使用Anaconda的人，当你使用chocoley Refreshenv命令时;所有与conda相关的环境变量都将丢失。 要解决这个问题，最好的方法是重新启动CMD。：(

以下是Chocolatey使用的方法。

https://github.com/chocolatey/choco/blob/master/src/chocolatey.resources/redirects/RefreshEnv.cmd

@echo off
::
:: RefreshEnv.cmd
::
:: Batch file to read environment variables from registry and
:: set session variables to these values.
::
:: With this batch file, there should be no need to reload command
:: environment every time you want environment changes to propagate

::echo "RefreshEnv.cmd only works from cmd.exe, please install the Chocolatey Profile to take advantage of refreshenv from PowerShell"
echo | set /p dummy="Refreshing environment variables from registry for cmd.exe. Please wait..."

goto main

:: Set one environment variable from registry key
:SetFromReg
    "%WinDir%\System32\Reg" QUERY "%~1" /v "%~2" > "%TEMP%\_envset.tmp" 2>NUL
    for /f "usebackq skip=2 tokens=2,*" %%A IN ("%TEMP%\_envset.tmp") do (
        echo/set "%~3=%%B"
    )
    goto :EOF

:: Get a list of environment variables from registry
:GetRegEnv
    "%WinDir%\System32\Reg" QUERY "%~1" > "%TEMP%\_envget.tmp"
    for /f "usebackq skip=2" %%A IN ("%TEMP%\_envget.tmp") do (
        if /I not "%%~A"=="Path" (
            call :SetFromReg "%~1" "%%~A" "%%~A"
        )
    )
    goto :EOF

:main
    echo/@echo off >"%TEMP%\_env.cmd"

    :: Slowly generating final file
    call :GetRegEnv "HKLM\System\CurrentControlSet\Control\Session Manager\Environment" >> "%TEMP%\_env.cmd"
    call :GetRegEnv "HKCU\Environment">>"%TEMP%\_env.cmd" >> "%TEMP%\_env.cmd"

    :: Special handling for PATH - mix both User and System
    call :SetFromReg "HKLM\System\CurrentControlSet\Control\Session Manager\Environment" Path Path_HKLM >> "%TEMP%\_env.cmd"
    call :SetFromReg "HKCU\Environment" Path Path_HKCU >> "%TEMP%\_env.cmd"

    :: Caution: do not insert space-chars before >> redirection sign
    echo/set "Path=%%Path_HKLM%%;%%Path_HKCU%%" >> "%TEMP%\_env.cmd"

    :: Cleanup
    del /f /q "%TEMP%\_envset.tmp" 2>nul
    del /f /q "%TEMP%\_envget.tmp" 2>nul

    :: capture user / architecture
    SET "OriginalUserName=%USERNAME%"
    SET "OriginalArchitecture=%PROCESSOR_ARCHITECTURE%"

    :: Set these variables
    call "%TEMP%\_env.cmd"

    :: Cleanup
    del /f /q "%TEMP%\_env.cmd" 2>nul

    :: reset user / architecture
    SET "USERNAME=%OriginalUserName%"
    SET "PROCESSOR_ARCHITECTURE=%OriginalArchitecture%"

    echo | set /p dummy="Finished."
    echo .

如果它只涉及一个(或几个)特定的变量，你想要改变，我认为最简单的方法是一个变通方法:在你的环境和当前的控制台会话中设置

Set将把变量放在当前会话中 SetX将把变量放在环境中，但不是在当前会话中

我使用这个简单的批处理脚本将Maven从Java7更改为Java8(两者都是env。批处理文件夹在我的PATH变量中，所以我总是可以调用'j8'，在我的控制台和环境中，我的JAVA_HOME变量被改变:

j8.bat:

@echo off
set JAVA_HOME=%JAVA_HOME_8%
setx JAVA_HOME "%JAVA_HOME_8%"

到目前为止，我发现这是最好的和最简单的工作。 你可能希望这是在一个命令中，但它只是没有在Windows…

这适用于windows 7: SET PATH=%PATH%

通过输入echo %PATH%测试，它工作正常。也设置如果你打开一个新的cmd，不需要那些讨厌的重新启动:)

可以通过在指定进程本身中覆盖环境表来实现这一点。

作为概念的证明，我写了这个示例应用程序，它只是在cmd.exe进程中编辑一个(已知的)环境变量:

typedef DWORD (__stdcall *NtQueryInformationProcessPtr)(HANDLE, DWORD, PVOID, ULONG, PULONG);

int __cdecl main(int argc, char* argv[])
{
    HMODULE hNtDll = GetModuleHandleA("ntdll.dll");
    NtQueryInformationProcessPtr NtQueryInformationProcess = (NtQueryInformationProcessPtr)GetProcAddress(hNtDll, "NtQueryInformationProcess");

    int processId = atoi(argv[1]);
    printf("Target PID: %u\n", processId);

    // open the process with read+write access
    HANDLE hProcess = OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION | PROCESS_VM_READ | PROCESS_VM_WRITE | PROCESS_VM_OPERATION, 0, processId);
    if(hProcess == NULL)
    {
        printf("Error opening process (%u)\n", GetLastError());
        return 0;
    }

    // find the location of the PEB
    PROCESS_BASIC_INFORMATION pbi = {0};
    NTSTATUS status = NtQueryInformationProcess(hProcess, ProcessBasicInformation, &pbi, sizeof(pbi), NULL);
    if(status != 0)
    {
        printf("Error ProcessBasicInformation (0x%8X)\n", status);
    }
    printf("PEB: %p\n", pbi.PebBaseAddress);

    // find the process parameters
    char *processParamsOffset = (char*)pbi.PebBaseAddress + 0x20; // hard coded offset for x64 apps
    char *processParameters = NULL;
    if(ReadProcessMemory(hProcess, processParamsOffset, &processParameters, sizeof(processParameters), NULL))
    {
        printf("UserProcessParameters: %p\n", processParameters);
    }
    else
    {
        printf("Error ReadProcessMemory (%u)\n", GetLastError());
    }

    // find the address to the environment table
    char *environmentOffset = processParameters + 0x80; // hard coded offset for x64 apps
    char *environment = NULL;
    ReadProcessMemory(hProcess, environmentOffset, &environment, sizeof(environment), NULL);
    printf("environment: %p\n", environment);

    // copy the environment table into our own memory for scanning
    wchar_t *localEnvBlock = new wchar_t[64*1024];
    ReadProcessMemory(hProcess, environment, localEnvBlock, sizeof(wchar_t)*64*1024, NULL);

    // find the variable to edit
    wchar_t *found = NULL;
    wchar_t *varOffset = localEnvBlock;
    while(varOffset < localEnvBlock + 64*1024)
    {
        if(varOffset[0] == '\0')
        {
            // we reached the end
            break;
        }
        if(wcsncmp(varOffset, L"ENVTEST=", 8) == 0)
        {
            found = varOffset;
            break;
        }
        varOffset += wcslen(varOffset)+1;
    }

    // check to see if we found one
    if(found)
    {
        size_t offset = (found - localEnvBlock) * sizeof(wchar_t);
        printf("Offset: %Iu\n", offset);

        // write a new version (if the size of the value changes then we have to rewrite the entire block)
        if(!WriteProcessMemory(hProcess, environment + offset, L"ENVTEST=def", 12*sizeof(wchar_t), NULL))
        {
            printf("Error WriteProcessMemory (%u)\n", GetLastError());
        }
    }

    // cleanup
    delete[] localEnvBlock;
    CloseHandle(hProcess);

    return 0;
}

样例输出:

>set ENVTEST=abc

>cppTest.exe 13796
Target PID: 13796
PEB: 000007FFFFFD3000
UserProcessParameters: 00000000004B2F30
environment: 000000000052E700
Offset: 1528

>set ENVTEST
ENVTEST=def

笔记

这种方法也仅限于安全限制。如果目标在更高的海拔或更高的帐户(如SYSTEM)上运行，那么我们将没有权限编辑它的内存。

如果你想对一个32位的应用程序这样做，上面的硬编码偏移量将分别更改为0x10和0x48。这些偏移量可以通过在调试器中转储_PEB和_RTL_USER_PROCESS_PARAMETERS结构体来找到(例如在WinDbg dt _PEB和dt _RTL_USER_PROCESS_PARAMETERS中)

要将概念证明更改为OP需要的内容，只需枚举当前系统和用户环境变量(如@tsadok的答案所记录的那样)，并将整个环境表写入目标进程的内存中。

Edit: The size of the environment block is also stored in the _RTL_USER_PROCESS_PARAMETERS struct, but the memory is allocated on the process' heap. So from an external process we wouldn't have the ability to resize it and make it larger. I played around with using VirtualAllocEx to allocate additional memory in the target process for the environment storage, and was able to set and read an entirely new table. Unfortunately any attempt to modify the environment from normal means will crash and burn as the address no longer points to the heap (it will crash in RtlSizeHeap).