A correct way to convert byte[] in java to unsigned char* in C++, and vice versa?

Question

I'm newbie in C++ and JNI, I try to find a correct way to convert byte[] in java to unsigned char* in C++ by using JNI, and vice versa ! (I'm working on android) After looking for a solution in google and SO, I haven't found a good details way to convert byte[] in java to C++. Please help me, and provide a solution for a vice versa (unsigned char* in C++ to byte[] in java). Thanks very much

• byte[] in java to unsigned char* in C++:

JAVA :

private static native void nativeReceiveDataFromServer(byte[] value, int length); 

JNI:

... (JNIEnv* env, jobject thiz, jbyteArray array, jint array_length) {     ??? } 

PS: I modified my question for being a real question for my problem :(

Answer 1

You can use this to convert unsigned char array into a jbyteArray

jbyteArray as_byte_array(unsigned char* buf, int len) {     jbyteArray array = env->NewByteArray (len);     env->SetByteArrayRegion (array, 0, len, reinterpret_cast<jbyte*>(buf));     return array; } 

to convert the other way around...

unsigned char* as_unsigned_char_array(jbyteArray array) {     int len = env->GetArrayLength (array);     unsigned char* buf = new unsigned char[len];     env->GetByteArrayRegion (array, 0, len, reinterpret_cast<jbyte*>(buf));     return buf; }