test_mynative.cpp

java中实现jni调用,jni调用dll ,dll再调用dll ,dll显示调用

#include <stdio.h>
#include "test_MyNative.h"

#include "windows.h"

typedef int ( * lpAddFun)(int,int);


JNIEXPORT void JNICALL Java_test_MyNative_HelloWord(JNIEnv *env, jclass jobject)
{ printf("hello word!\n"); 
}

JNIEXPORT jstring JNICALL Java_test_MyNative_cToJava(JNIEnv *env, jclass obj)
{
	jstring jstr;
	char str[]="Hello,word!\n";
	jstr=env->NewStringUTF(str);
	return jstr;
}

JNIEXPORT jint JNICALL Java_test_MyNative_add(JNIEnv *env, jclass obj, jint a, jint b)
{
	HINSTANCE hDll;   //DLL句柄	
	lpAddFun addFun;  //函数指针
    hDll = LoadLibrary(".\\dllTest.dll");
    int result=0;
	if (hDll != NULL)
	{
		addFun = (lpAddFun)GetProcAddress(hDll,"add");	
		if(addFun!=NULL)
		{
		    result =  addFun(2,3);    
			//printf("%d",result);
		}
		FreeLibrary(hDll);
	}	
    return result;
}