2018-11-29 java和dll交互

参考文章《JNA：JAVA调用DLL 超详细代码实战》和《JNA Examples》实现了java和c实现的dll相互调用，细节如下：

1、dll生成

我们继续使用《Golang与DLL交互》一样的c代码

使用vs2013生成dll库，添加代码如下：

// testdll.cpp : 定义 DLL 应用程序的导出函数。

//

#include "stdafx.h"

#include <stdio.h>

#ifndef TM_ROBOT_API

#define TM_ROBOT_API extern "C" __declspec(dllexport)

#else

#define TM_ROBOT_API extern "C" __declspec(dllimport)

#endif

TM_ROBOT_API void fun1(int* pVal) {

char buff[128];

sprintf_s(buff, "fun1, val: %d -> 999\n", *pVal);

OutputDebugStringA(buff);

*pVal = 999;

}

struct MyStruct

{

int nVal1;

float nVal2;

};

typedef int(*CB_MY)(int nVal, int fVal);

TM_ROBOT_API void fun2(MyStruct* pVal) {

char buff[128];

sprintf_s(buff, "fun2, val: 1->%d, 2->%.4f -> 1,2\n", pVal->nVal1, pVal->nVal2);

OutputDebugStringA(buff);

pVal->nVal1 = 1;

pVal->nVal2 = 2.2;

}

TM_ROBOT_API void fun3(CB_MY pFun) {

char buff[128];

sprintf_s(buff, "fun3, val: %08X -> call it 10s\n", pFun);

OutputDebugStringA(buff);

for (int i = 80; i<100; i++)

{

pFun((int)(i*3.3), (int)(i*1.1));

Sleep(10);

}

}

特别注意的是系统64为要生成64位的dll

2、java代码--jna接口，HelloInterface.java

package com.test.hellojna;

import java.util.Arrays;

import java.util.List;

import com.sun.jna.Callback;

import com.sun.jna.Library;

import com.sun.jna.Structure;

import com.sun.jna.ptr.IntByReference;

public interface HelloInterface extends Library {

public void fun1(IntByReference  pVal);

public void fun2(MyStruct.ByReference pVal);

public void fun3(CB_MY pFun);

// define an interface that wraps the callback code

public interface CB_MY extends Callback {

int invoke(int nVal,int fVal);

}

public static class MyStruct extends Structure {

public static class ByReference extends MyStruct implements Structure.ByReference {

}

public int nVal1;

public float nVal2;

@Override

protected List<String> getFieldOrder() {

return Arrays.asList(new String[] { "nVal1", "nVal2" });

}

}

}

这里注意的是指针的地方都是对应相应的Reference类

结构体的特殊定义和回调函数的特殊定义

3、java代码-dll接口实例，HelloBase.java

package com.test.hellojna;

import com.sun.jna.Native;

public class HelloBase {

public static HelloInterface instance = null;

public static HelloInterface getInstance() {

if (instance != null)

return instance;

try {

instance = (HelloInterface)Native.loadLibrary("testdll", HelloInterface.class);

} catch (Exception e) {

e.printStackTrace();

}

return instance;

}

}

4、java代码--测试代码，App.java

package com.test.hellojna;

import com.sun.jna.ptr.IntByReference;

import com.test.hellojna.HelloInterface.CB_MY;

/**

* Hello world!

*

*/

public class App

{

    public static void main( String[] args )

    {

    HelloInterface myinterface = HelloBase.getInstance();

    int aa = 10;

    final IntByReference aa_valRef = new IntByReference(aa);

    myinterface.fun1(aa_valRef);

    System.out.println("########" + aa_valRef.getValue());

    final HelloInterface.MyStruct.ByReference arg1 = new HelloInterface.MyStruct.ByReference();

    arg1.nVal1 = 11;

    arg1.nVal2 = 22.22f;

    myinterface.fun2(arg1);

    System.out.println("************" + "nVal1=" + arg1.nVal1 + ",nVal2=" + arg1.nVal2);

    myinterface.fun3(new CB_MY() {

    public int invoke(int nVal,int fVal) {

        System.out.println("cb_my:" + nVal+ " " + fVal);

        return 0;

    }

    }) ;

    System.out.println("============");

    }

}

这里要注意的是Reference相关的都需要new

具体工程代码放在csdn：