Jni中基本型別轉換對應的表格

Java程式碼:

package com.example.jni;

public class NativeUtil {
// String 轉換
public static native String getJniString();
// int轉換
public static native int getJniInt();
// boolean轉換
public static native boolean getJniBoolean();
// double轉換
public static native double getJniDouble();
// float轉換
public static native float getJniFloat();
// Byte轉換
public static native float getJniByte();
// Byte陣列轉換
public static native byte[] getJniByteArray();
// String陣列轉換
public static native String[] getJniStringArray();
// int陣列轉換
public static native int[] getJniIntArray();
// Long陣列轉換
public static native long[] getJniLongArray();
}
 

C程式碼:

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_example_jni_NativeUtil */
#ifndef _Included_com_example_jni_NativeUtil
#define _Included_com_example_jni_NativeUtil
#define SEED_SIZE 20
#ifdef __cplusplus
extern "C" {
#endif
/*
 *  String 轉換
 * Class:     com_example_jni_NativeUtil
 * Method:    getJniString
 * Signature: ()Ljava/lang/String;
 */
JNIEXPORT jstring JNICALL Java_com_example_jni_NativeUtil_getJniString(
JNIEnv *env, jclass jobj) {
//    GetStringUTFChars
return (*env)->NewStringUTF(env, "Hello JNI!");
}
/*
 * int 轉換
 * Class:     com_example_jni_NativeUtil
 * Method:    getJniInt
 * Signature: ()I
 */
JNIEXPORT jint JNICALL Java_com_example_jni_NativeUtil_getJniInt(JNIEnv *env,
jclass jobj) {
int i = 13;
return (jint) i;
}
/*
 * boolean轉換
 * Class:     com_example_jni_NativeUtil
 * Method:    getJniBoolean
 * Signature: ()Z
 */
JNIEXPORT jboolean JNICALL Java_com_example_jni_NativeUtil_getJniBoolean(
JNIEnv *env, jclass jobj) {
unsigned char b = 0;
return (jboolean) b;
}
/*
 * double轉換
 * Class:     com_example_jni_NativeUtil
 * Method:    getJniDouble
 * Signature: ()D
 */
JNIEXPORT jdouble JNICALL Java_com_example_jni_NativeUtil_getJniDouble(
JNIEnv *env, jclass jobj) {
double d = 888.88;
return (jdouble) d;
}
/*
 * float轉換
 * Class:     com_example_jni_NativeUtil
 * Method:    getJniFloat
 * Signature: ()F
 */
JNIEXPORT jfloat JNICALL Java_com_example_jni_NativeUtil_getJniFloat(
JNIEnv *env, jobject jobj) {
jbyte b = 5;
return (jbyte) b;
}
/*
 * byte轉換
 * Class:     com_example_jni_NativeUtil
 * Method:    getJniByte
 * Signature: ()F
 */
JNIEXPORT jfloat JNICALL Java_com_example_jni_NativeUtil_getJniByte(JNIEnv *env,
jobject jobj) {
jfloat f = 5;
return (jfloat) f;
}
/*
 * byte陣列轉換
 * Class:     com_example_jni_NativeUtil
 * Method:    getJniByteArray
 * Signature: ()[B
 */
JNIEXPORT jbyteArray JNICALL Java_com_example_jni_NativeUtil_getJniByteArray(
JNIEnv *env, jobject jobj) {
int i = 0;
jbyteArray array = (*env)->NewByteArray(env, 16);
jbyte tmp_aeskey[16];
for (i = 0; i < 16; i++) {
jbyte b = 5;
tmp_aeskey[i] = b;
}
(*env)->SetByteArrayRegion(env, array, 0, 16, tmp_aeskey);
return array;
}
/**
 * int陣列轉換
 */
JNIEXPORT jintArray JNICALL Java_com_example_jni_NativeUtil_getJniIntArray(
JNIEnv *env, jobject jobj) {
int i = 1;
jintArray array; //定義陣列物件
array = (*env)->NewIntArray(env, 10);
for (; i <= 10; i++) {
(*env)->SetIntArrayRegion(env, array, i - 1, 1, &i);
}
jint* elems = (*env)->GetIntArrayElements(env, array, 0);
return array;
}
/**
 * long陣列轉換
 */
JNIEXPORT jlongArray JNICALL Java_com_example_jni_NativeUtil_getJniLongArray(
JNIEnv *env, jobject jobj) {
int i = 1;
jlongArray array; //定義陣列物件
array = (*env)->NewLongArray(env, 10);
for (; i <= 10; i++) {
(*env)->SetLongArrayRegion(env, array, i - 1, 1, &i);
}
jint* elems = (*env)->GetLongArrayElements(env, array, 0);
return array;
}
#ifdef __cplusplus
}
#endif
#endif