如何在加载 DLL 时加载 JVM 并在卸载 DLL 时释放它

Question

我正在开发一个 dll，它调用一个 jar 通过 JNI 完成大部分工作。如何创建 DLL，使其在加载 DLL 时仅创建一次 JVM，并在卸载 DLL 时释放它？

Answer 1

提供一个 DllMain 函数，其模式如下：

BOOL WINAPI DllMain(
    HINSTANCE hinstDLL,  // handle to DLL module
    DWORD fdwReason,     // reason for calling function
    LPVOID lpReserved)     // reserved
{
    // Perform actions based on the reason for calling.
    switch(fdwReason)
    {
        case DLL_PROCESS_ATTACH:
            // Initialize once for each new process.
            // Return FALSE to fail DLL load.
            LOAD_JVM(); // <-----------------------------------------
            break;
        case DLL_THREAD_ATTACH:
            // Do thread-specific initialization.
            break;
        case DLL_THREAD_DETACH:
            // Do thread-specific cleanup.
            break;
        case DLL_PROCESS_DETACH:
            // Perform any necessary cleanup.
            UNLOAD_JVM(); // <-----------------------------------------
            break;
    }
    // Successful DLL_PROCESS_ATTACH.
    return TRUE;
}