Java JDK18 外来函数：如何处理多个同名但来自不同本机库的函数

FWIW，执行此操作所需的API设置为public in 19

在此之前，建议通过绑定dlopen、dlclose和dlsym(或Windows等效项)来手动实现这一点，以加载库和查找符号.

例如，在我的Windows计算机上:

public class Main {
    
    static final MethodHandle MH_LoadLibraryA;
    static final MethodHandle MH_FreeLibrary;
    static final MethodHandle MH_GetProcAddress;

    static {
        System.loadLibrary("Kernel32");
        SymbolLookup lookup = SymbolLookup.loaderLookup();
        CLinker linker = CLinker.systemCLinker();
        MH_LoadLibraryA = linker.downcallHandle(
            lookup.lookup("LoadLibraryA").orElseThrow(),
            FunctionDescriptor.of(ADDRESS, ADDRESS));
        MH_FreeLibrary = linker.downcallHandle(
            lookup.lookup("FreeLibrary").orElseThrow(),
            FunctionDescriptor.of(JAVA_INT, ADDRESS));
        MH_GetProcAddress = linker.downcallHandle(
            lookup.lookup("GetProcAddress").orElseThrow(),
            FunctionDescriptor.of(ADDRESS, ADDRESS, ADDRESS));
    }

    static MemoryAddress LoadLibraryA(String name) {
        try (ResourceScope scope = ResourceScope.newConfinedScope()) {
            SegmentAllocator allocator = SegmentAllocator.nativeAllocator(scope);
            return (MemoryAddress) MH_LoadLibraryA.invokeExact((Addressable) allocator.allocateUtf8String(name));
        } catch (Throwable t) {
            throw new RuntimeException(t);
        }
    }

    static boolean FreeLibrary(MemoryAddress handle) {
        try {
            return ((int) MH_FreeLibrary.invokeExact((Addressable) handle)) != 0;
        } catch (Throwable t) {
            throw new RuntimeException(t);
        }
    }

    static MemoryAddress GetProcAddress(MemoryAddress handle, String name) {
        try (ResourceScope scope = ResourceScope.newConfinedScope()) {
            SegmentAllocator allocator = SegmentAllocator.nativeAllocator(scope);
            return (MemoryAddress) MH_GetProcAddress.invokeExact((Addressable) handle, (Addressable) allocator.allocateUtf8String(name));
        } catch (Throwable t) {
            throw new RuntimeException(t);
        }
    }
    
    static SymbolLookup libraryLookup(String libraryName, ResourceScope scope) {
        MemoryAddress handle = LoadLibraryA(libraryName);
        if (handle == MemoryAddress.NULL) {
            throw new IllegalArgumentException("Cannot find library: " + libraryName);
        }
        scope.addCloseAction(() -> FreeLibrary(handle));
        return name -> {
            var addr = GetProcAddress(handle, name);
            return addr == MemoryAddress.NULL ?
                Optional.empty() : Optional.of(NativeSymbol.ofAddress(name, addr, scope));
        };
    }

    public static void main(String[] args) throws Throwable {
        try (ResourceScope scope = ResourceScope.newConfinedScope()) {
            SymbolLookup lookup = libraryLookup("gg", scope);
            MethodHandle handle = CLinker.systemCLinker().downcallHandle(
                lookup.lookup("get_gg").orElseThrow(),
                FunctionDescriptor.of(JAVA_INT));
            int x = (int) handle.invoke();
            System.out.println(x);
        }
    }
}