1.创建一个java工程
目录结构如下
2.在RunDLL类中编写native接口
内容如下
package com.android.dll;
public class RunDLL {
public native int getCounts();
public native void setCounts(int Counts);
public native void start();
public native void finish();
}
3.使用javah命令生成头文件
在命令行中进入到工程的bin目录,执行下面的 命令生成.h头文件
javah com.android.dll.RunDLL
4.在VC++6.0中编译dll文件
(1)创建一个空的dll工程
(2)创建一个头文件将刚才命令行中生成的头文件的内容导入进去
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_android_dll_RunDLL */
#ifndef _Included_com_android_dll_RunDLL
#define _Included_com_android_dll_RunDLL
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class: com_android_dll_RunDLL
* Method: getCounts
* Signature: ()I
*/
JNIEXPORT jint JNICALL Java_com_android_dll_RunDLL_getCounts
(JNIEnv *, jobject);
/*
* Class: com_android_dll_RunDLL
* Method: setCounts
* Signature: (I)V
*/
JNIEXPORT void JNICALL Java_com_android_dll_RunDLL_setCounts
(JNIEnv *, jobject, jint);
/*
* Class: com_android_dll_RunDLL
* Method: start
* Signature: ()V
*/
JNIEXPORT void JNICALL Java_com_android_dll_RunDLL_start
(JNIEnv *, jobject);
/*
* Class: com_android_dll_RunDLL
* Method: finish
* Signature: ()V
*/
JNIEXPORT void JNICALL Java_com_android_dll_RunDLL_finish
(JNIEnv *, jobject);
#ifdef __cplusplus
}
#endif
#endif
(3)创建一个C++源文件,内容如下
#include "com_android_dll_RunDLL.h"
#include "stdio.h"
int counts=0;
JNIEXPORT jint JNICALL Java_com_android_dll_RunDLL_getCounts
(JNIEnv *, jobject)
{
printf("getCount------------------\n");
return counts;
}
JNIEXPORT void JNICALL Java_com_android_dll_RunDLL_setCounts
(JNIEnv *, jobject, jint _counts)
{
printf("setCount------------------\n");
counts=_counts;
}
JNIEXPORT void JNICALL Java_com_android_dll_RunDLL_start
(JNIEnv *, jobject)
{
printf("start---------------------\n");
}
JNIEXPORT void JNICALL Java_com_android_dll_RunDLL_finish
(JNIEnv *, jobject)
{
printf("finish---------------------\n");
}
(4)切换到release模式,按F5编译成dll文件
debug和release的切换方式是,在工具栏的空白出右键,选择组建就会看到切换选项卡了
(5)如果这时会报一些头文件找不到的错误
只要将JAVA_HOME/include/jni.h和JAVA_HOME/include/win32/jni_md.h这两个文件拷贝到Microsoft Visual Studio\VC98\Include目录下就可以了
5.在java工程中调用
(1)调用的类
package com.android.dlltest;
import com.android.dll.RunDLL;
public class Test {
public static void main(String[] args) {
System.load("E:\\work\\DLLTest\\DLLTest.dll");
RunDLL rd=new RunDLL();
rd.start();
rd.setCounts(12);
int counts = rd.getCounts();
System.out.println("counts is------"+counts);
rd.finish();
}
}
(2)运行结果
counts is------12
start---------------------
setCount------------------
getCount------------------
finish---------------------