Java调用C++动态库、入参为对象

Java代码

调用类

package JniCallDLL;

import db.RFParaTypeInfo;
import db.XYZPosition;

public class JniDLL {
    public native int add(int a,int b);//在我写的实际需要调用的动态库中有加减乘除几个测试方法，我这里只测试了其中的add方法

    public native int sum(int a,int b);

    public native RFParaTypeInfo processRFPara(RFParaTypeInfo input);


    public native double processXYZPosition(XYZPosition input);

    static {
        System.loadLibrary("TestJniDLL");//这是我即将要重新实现的动态库名字
    }
}

入参类

/**
 * @author 28081
 */
public class XYZPosition {
    private double X;
    private double Y;

    public XYZPosition(double x, double y) {
        this.X = x;
        this.Y = y;
    }

    public double getX() {
        return X;
    }

    public double getY() {
        return Y;
    }
}

Java调用代码

package JniCallDLL;

import db.RFParaTypeInfo;
import db.XYZPosition;

public class RunDllCall {
    public static  void main(String[] args)
    {
        JniDLL jniDll = new JniDLL();
        System.out.println(jniDll.add(2,3));
        System.out.println(jniDll.sum(2,3));
        XYZPosition xyz=new XYZPosition(5,6);

        System.out.println(jniDll.processXYZPosition(xyz));

        String str="";
    }
}

C++代码

#include "TestJniDLL.h"
#include <iostream>
#include <stdio.h>
#include "JniCallDLL_JniDLL.h"
#include <Windows.h> //HMODULE
#include <tchar.h> //_T

typedef int(*Dllfun)(int, int);//定义一个名为Dllfun的返回值和两个参数都为int的函数指针
JNIEXPORT jint JNICALL Java_JniCallDLL_JniDLL_add
(JNIEnv*, jobject, jint a, jint b) {
	//HMODULE hinst=LoadLibrary(_T("MyMFCLibrary.dll"));//加载第三方动态库，不带路劲的话，默认就在当前动态库的相同路径下，带路径的话，路径的'\'需要写成'\\'
	//if (hinst==NULL)
	//{
	//	return 0;//调用第三方动态库失败
	//}
	//Dllfun dllfun = (Dllfun)GetProcAddress(hinst, "myAdd"); //获取第三方动态库中的add()方法

	//int result = dllfun(a, b);//调用add()方法
	return 20;
}


JNIEXPORT jint JNICALL Java_JniCallDLL_JniDLL_sum
(JNIEnv*, jobject, jint a, jint b) {
	//HMODULE hinst=LoadLibrary(_T("MyMFCLibrary.dll"));//加载第三方动态库，不带路劲的话，默认就在当前动态库的相同路径下，带路径的话，路径的'\'需要写成'\\'
	//if (hinst==NULL)
	//{
	//	return 0;//调用第三方动态库失败
	//}
	//Dllfun dllfun = (Dllfun)GetProcAddress(hinst, "myAdd"); //获取第三方动态库中的add()方法

	//int result = dllfun(a, b);//调用add()方法
	return 50;
}


JNIEXPORT jdouble JNICALL Java_JniCallDLL_JniDLL_processXYZPosition(JNIEnv* env, jobject obj, jobject position) {

	// 1. 获取XYZPosition的类引用
	jclass cls = env->GetObjectClass(position);
	if (cls == nullptr) {
		std::cerr << "Failed to get class reference." << std::endl;
		return 1;
	}

	// 2. 获取getX和getY方法的ID
	jmethodID midGetX = env->GetMethodID(cls, "getX", "()D");
	jmethodID midGetY = env->GetMethodID(cls, "getY", "()D");
	if (midGetX == nullptr || midGetY == nullptr) {
		std::cerr << "Failed to get method IDs." << std::endl;
		return 1;
	}

	// 3. 调用方法获取值
	jdouble x = env->CallDoubleMethod(position, midGetX);
	jdouble y = env->CallDoubleMethod(position, midGetY);

	// 4. 输出结果

	std::cout << "X: " << x << ", Y: " << y << std::endl;


	const char* nativeString = "Hello from native code";
	jstring strRes = env->NewStringUTF(nativeString);

	jdouble re = x * y;
	return re;
}



TestJniDLL::TestJniDLL()
{
}


TestJniDLL::~TestJniDLL()
{
}

C++对外调用方法

/* DO NOT EDIT THIS FILE - it is machine generated */
#include "jni.h"
/* Header for class JniCallDLL_JniDLL */

#ifndef _Included_JniCallDLL_JniDLL
#define _Included_JniCallDLL_JniDLL
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     JniCallDLL_JniDLL
 * Method:    add
 * Signature: (II)I
 */
JNIEXPORT jint JNICALL Java_JniCallDLL_JniDLL_add
  (JNIEnv *, jobject, jint, jint);

JNIEXPORT jint JNICALL Java_JniCallDLL_JniDLL_sum
(JNIEnv*, jobject, jint, jint);


JNIEXPORT jdouble JNICALL Java_JniCallDLL_JniDLL_processXYZPosition
(JNIEnv* env, jobject obj, jobject position);


#ifdef __cplusplus
}
#endif
#endif

输出结果

（比较忙、后续详细讲下）