Java调用C#动态库的三种方法详解

// CSharpLibrary.cs
using System;

namespace CSharpLibrary {
    public class Calculator {
        public int Add(int a, int b) {
            return a + b;
        }
    }
}

// CppWrapper.h
#pragma once

#include <windows.h>

// 导出C风格函数供Java调用
extern "C" __declspec(dllexport) int AddFromCSharp(int a, int b);

// 实现：调用C#的Add方法
int AddFromCSharp(int a, int b) {
    // 创建C#对象
    CSharpLibrary::Calculator^ calc = gcnew CSharpLibrary::Calculator();
    return calc->Add(a, b);
}

// NativeExample.java
public class NativeExample {
    // 加载C++ DLL
    static {
        System.loadLibrary("CppMethod"); // 加载CppMethod.dll
    }

    // 声明本地方法
    public native static int addFromCSharp(int a, int b);

    public static void main(String[] args) {
        int result = addFromCSharp(3, 5);
        System.out.println("结果：" + result); // 输出“结果：8”
    }
}

// CppLibrary.java
import com.sun.jna.Library;
import com.sun.jna.Native;
import com.sun.jna.Platform;

public interface CppLibrary extends Library {
    CppLibrary INSTANCE = Native.load("CppMethod", CppLibrary.class); // 加载CppMethod.dll
    int AddFromCSharp(int a, int b); // 对应C++导出的AddFromCSharp函数
}

// 调用示例
public class JnaExample {
    public static void main(String[] args) {
        int result = CppLibrary.INSTANCE.AddFromCSharp(3, 5);
        System.out.println("结果：" + result); // 输出“结果：8”
    }
}

// CSharpCInterface.cs
using System;
using System.Runtime.InteropServices;

// 用C风格导出函数
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool FreeLibrary(IntPtr hModule);

public class CSharpCInterface {
    [DllExport("AddFromCSharp", CallingConvention = CallingConvention.Cdecl)]
    public static int AddFromCSharp(int a, int b) {
        return a + b;
    }
}

// CSharpLibrary.java
import com.sun.jna.Library;
import com.sun.jna.Native;
import com.sun.jna.Platform;

public interface CSharpLibrary extends Library {
    CSharpLibrary INSTANCE = Native.load("CSharpCInterface", CSharpLibrary.class); // 加载CSharpCInterface.dll
    int AddFromCSharp(int a, int b); // 对应C#导出的AddFromCSharp函数
}

// 调用示例
public class JnaExample {
    public static void main(String[] args) {
        int result = CSharpLibrary.INSTANCE.AddFromCSharp(3, 5);
        System.out.println("结果：" + result); // 输出“结果：8”
    }
}

// CSharpComLibrary.cs
using System;
using System.Runtime.InteropServices;

// 定义COM接口
[ComVisible(true)]
[Guid("A1B2C3D4-E5F6-7890-ABCD-1234567890EF")]
[InterfaceType(ComInterfaceType.InterfaceIsDual)]
public interface ICalculator {
    int Add(int a, int b);
}

// 实现COM接口
[ComVisible(true)]
[Guid("A1B2C3D4-E5F6-7890-ABCD-1234567890FF")]
[ClassInterface(ClassInterfaceType.None)]
public class Calculator : ICalculator {
    public int Add(int a, int b) {
        return a + b;
    }
}

// ComExample.java
import com.jacob.activeX.ActiveXComponent;
import com.jacob.com.Dispatch;
import com.jacob.com.Variant;

public class ComExample {
    public static void main(String[] args) {
        ActiveXComponent calculator = new ActiveXComponent("CSharpComLibrary.Calculator");
        Dispatch calcDispatch = calculator.getActiveXComponent();
        Variant result = Dispatch.call(calcDispatch, "Add", 3, 5);
        System.out.println("结果：" + result.getInt()); // 输出“结果：8”
    }
}