<b>JNI简单示例</b>[Java编程]

Java通过JNI调用本地系统的动态库(Windows上是dll情势,Unix中是so情势的文件).JNI的简单步骤 以下:

Step1:编写Java类,此中包含要实现的native办法.

JNITest.java:

public class JNITest{
static{
System.loadLibrary("JNITest");
}

public native void showMessageBox();

public static void main(String[] args){
JNITest jni = new JNITest();
jni.showMessageBox();
}
}

编译JNITest.java,号令:"javac JNITest.java",生成JNITest.class.

Step2:生成头文件,号令:"javah JNITest",生成头文件JNITest.h

JNITest.h:

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

#ifndef _Included_JNITest
#define _Included_JNITest
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class:　　　　 JNITest
* Method:　　　 showMessageBox
* Signature: ()V
*/
JNIEXPORT void JNICALL Java_JNITest_showMessageBox
(JNIEnv *, jobject);

#ifdef __cplusplus
}
#endif
#endif

Step3:编写呼应的实现文件JNITest.cpp(或.c).

JNITest.cpp:

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

JNIEXPORT void JNICALL Java_JNITest_showMessageBox
(JNIEnv *, jobject){
::MessageBox(NULL,"This is a JNI test" , "JNI" , MB_OK);
}

Step4:将JNITest.cpp编译成dll,

号令(cl是VC6的编译号令):

"cl -If:jdkinclude -If:jdkincludewin32 -LD JNITest.cpp user32.lib - FeJNITest.dll"

Step5:运行,号令:"java JNITest".运行后会弹出一个对话框.