被隐藏了的jni

public class HelloWorld {
   static {

       System.loadLibrary("Hello");
   }
   public     native void DisplayHello();
   public static void main(String[] args) {
       new HelloWorld().DisplayHello();
   }

}

javac HelloWorld.java
javah -jni HelloWorld
生成helloworld.h

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

#ifndef _Included_HelloWorld
#define _Included_HelloWorld
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     HelloWorld
 * Method:    DisplayHello
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_HelloWorld_DisplayHello
  (JNIEnv *, jobject);

#ifdef __cplusplus
}
#endif
#endif

根据.h生成的方法名写个cpp文件
HelloWorld.cpp

#include <jni.h>
#include "HelloWorld.h"
#include <stdio.h>
JNIEXPORT void JNICALL Java_HelloWorld_DisplayHello
(JNIEnv *env, jobject obj)
{
    printf("From jni_helloworldImpl.cpp :");
    printf("Hello world ! \n");
    return;
}

g++ -shared -I /usr/local/jdk/include/ -I /usr/local/jdk/include/linux/ -Wall -fPIC HelloWorld.cpp  -o libHello.so
java -Djava.library.path=. HelloWorld

注意一下要引入/usr/local/jdk/include/ 和/usr/local/jdk/include/linux/
还要加-Wall -fPIC