Primitive Types to JNI

JNI에서 자바 기본형 파라미터를 JNI함수에 전달하는 예

HelloJNI.java

public class HelloJNI {
   static{
      System.loadLibrary("my_dll");  
   }
   /* 기본형 파라미터를 전달하는 경우 */
   public native void printSize(boolean b, byte bt, short s, char c, int i, long lg, float f, double d);

   public static void main(String[] args) throws Exception{
      new HelloJNI().printSize(true, (byte)1, (short)2, 'A', 3, 4L, 5.0F, 6.0);
   }
}

HelloJNI.h

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

#ifndef _Included_HelloJNI
#define _Included_HelloJNI
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     HelloJNI
 * Method:    printSize
 * Signature: (ZBSCIJFD)V
 */
JNIEXPORT void JNICALL Java_HelloJNI_printSize
  (JNIEnv *, jobject, jboolean, jbyte, jshort, jchar, jint, jlong, jfloat, jdouble);

#ifdef __cplusplus
}
#endif
#endif

my_dll.c

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

JNIEXPORT void JNICALL Java_HelloJNI_printSize
(JNIEnv *env, jobject obj, jboolean b, jbyte bt, jshort s, jchar c, jint i, jlong lon, jfloat f, jdouble d){
 printf("jboolean size=%d \n", sizeof(b));
 printf("jbyte size=%d \n", sizeof(bt));
 printf("jshort size=%d \n", sizeof(s));
 printf("jchar size=%d \n", sizeof(c));
 printf("jint size=%d \n", sizeof(i));
 printf("jlong size=%d \n", sizeof(lon));
 printf("jfloat size=%d \n", sizeof(f));
 printf("jdouble size=%d \n", sizeof(d));
   return;
}

자바 클래스 실행결과

jboolean size=1
jbyte size=1
jshort size=2
jchar size=2
jint size=4
jlong size=8
jfloat size=4
jdouble size=8