JNI On Mac

1.首先在Java中声明本地方法. Java编程语言使用关键字native表示本地方法, 本地方法可以是静态的, 也可以是非静态的.

class HelloNative
{
    public static native void greeting();
}

2.使用javah工具生成头文件

javah HelloNative

3.生成HelloNative.h, 查看其内容

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

#ifndef _Included_HelloNative
#define _Included_HelloNative
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     HelloNative
 * Method:    greeting
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_HelloNative_greeting
  (JNIEnv *, jclass);

#ifdef __cplusplus
}
#endif
#endif

4.根据生成的接口, 定义函数内容

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

JNIEXPORT void JNICALL Java_HelloNative_greeting(JNIEnv* env, jclass cl)
{
    printf("Hello Native World!
");
}

5.使用C编译器编译C代码

export JDK=/System/Library/Frameworks/JavaVM.framework/Versions/A
gcc -dynamiclib 
	-I $JDK/Headers 
	-shared 
	-o libHelloNative.jnilib 
	HelloNative.c

6.编写调用代码

class HelloNativeTest
{
    public static void main(String[] args)
    {
        HelloNative.greeting();
    }

    static
    {
        System.loadLibrary("HelloNative");
    }
}

7.运行

javac HelloNative.java
javac HelloNativeTest.java
java -Djava.library.path=. HelloNativeTest