日期:2014-05-19  浏览次数:20702 次

100分求解!!java调用第三方dll中的函数
如题,现在有一个第三方的dll文件“Mwic_32.dll”,由于是第三方的,必须要用JNI实现,我的具体步骤如下:

先在java中定义一个类:
Java code
public class AAA {
    static {
        System.load("C:/AUTO_INIT.dll");
    }
    public native static int auto_init(int a,int b);
    public static void main(String args[]){
        AAA new_auto_init = new AAA();
        System.out.println("Result="+new_auto_init.auto_init(0, 38400));
    }
}



之后用javah AAA生成头文件AAA.h

在DEV C++中新建一个dll工程,名字为“AUTO_INIT”
之后复制AAA.h中的内容到AUTO_INIT.h的最前边
最后实现AUTO_INIT.cpp中的方法Java_AAA_auto_1init(调用Mwic_32.dll中的auto_init函数)
并生成AUTO_INIT.dll
其中,AUTO_INIT.h代码如下:
C/C++ code
/* DO NOT EDIT THIS FILE - it is machine generated */
#include "jni.h"
/* Header for class AAA */

#ifndef _Included_AAA
#define _Included_AAA
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     AAA
 * Method:    auto_init
 * Signature: (II)I
 */
JNIEXPORT jint JNICALL Java_AAA_auto_1init
  (JNIEnv *, jclass, jint, jint);

#ifdef __cplusplus
}
#endif
#endif


///////////////////////////////////////////////////////
#ifndef _DLL_H_
#define _DLL_H_

#if BUILDING_DLL
# define DLLIMPORT __declspec (dllexport)
#else /* Not BUILDING_DLL */
# define DLLIMPORT __declspec (dllimport)
#endif /* Not BUILDING_DLL */


class DLLIMPORT DllClass
{
  public:
    DllClass();
    virtual ~DllClass(void);

  private:

};


#endif /* _DLL_H_ */



AUTO_INIT.cpp代码:
C/C++ code
/* Replace "dll.h" with the name of your header */
#include<windows.h>
#include<stdio.h>

#include "AUTO_INIT.h"
#include <windows.h>

JNIEXPORT jint JNICALL Java_AAA_auto_1init
  (JNIEnv * nev, jclass obj, jint a, jint b){
          //const int * aa=a;
          //const int * bb=evn->GetInt(b); 
          //void * objptr = CreateAUTO_INIT();
          
          HINSTANCE hdll = NULL;
          hdll = LoadLibrary ( "Mwic_32.dll" );
          typedef BOOL ( _stdcall *lpFileEncrypt )( INT, INT);
          lpFileEncrypt FileEncrypt1;
          FileEncrypt1 = ( lpFileEncrypt )::GetProcAddress( hdll, "auto_init" );//调用dll中的函数
          int result = FileEncrypt1(0,38400);
          FreeLibrary( hdll );
          //printf("restult=%d",result);

          
          //int result=auto_init(a,b);
          //env->ReleaseInt(a,aa);
          //env->ReleaseInt(b,bb);
          return result;
  
          
  }





DllClass::DllClass()
{

}


DllClass::~DllClass ()
{

}


BOOL APIENTRY DllMain (HINSTANCE hInst     /* Library instance handle. */ ,
                       DWORD reason        /* Reason this function is being called. */ ,
                       LPVOID reserved     /* Not used. */ )
{
    switch (reason)
    {
      case DLL_PROCESS_ATTACH:
        break;

      case DLL_PROCESS_DETACH:
        break;

      case DLL_THREAD_ATTACH:
        break;

      case DLL_THREAD_DETACH:
        break;
    }

    /* Returns TRUE on success, FALSE on failure */
    return TRUE;
}



最后我把生成出来的AUTO_INIT.dll文件放在C盘下,但是用java运行是确提示“An unexpected error has been detected by Java Runtime Environment:”

具体的出错信息如下:
#
# An unexpected error has been detected by Java Runtime Environment:
#
# EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x00000000, pid=3644, tid=3696
#
# Java VM: Java HotSpot(TM) Client VM (11.0-b16 mixed mode, sharing windows-x86)
# Problematic frame:
# C 0x00000000
#
# An error report file with more infor