将 const unsigned char* 转换为 jbyteArray，反之亦然

Question

我有两个问题：如何将 const unsigned char* 转换为 jbyteArray？JNIEXPORT jbyteArray JNICALL Java_MyJavaApplication_readValue(JNIEnv* env, jobject obj){    const unsigned char* someConstUnsignedChar = (gcnew MyCSharpLibrary())->readValue();    // What should be here?    return someJbyteArray;}如何将 jbyteArray 转换为 const unsigned char*？JNIEXPORT jboolean JNICALL Java_MyJavaApplication_writeValue(JNIEnv* env, jobject obj, jbyteArray someJbyteArray){    // What should be here?    return (gcnew MyCSharpLibrary())->writeValue(someConstUnsignedChar);}

Answer 1

将 const unsigned char* 转换为 jbyteArray：

#include <tuple>

JNIEXPORT jbyteArray JNICALL Java_MyJavaApplication_readValue(JNIEnv* env, jobject obj)

{

    const unsigned char* someConstUnsignedChar;

    int len;

    std::tie(someConstUnsignedChar, len) = (gcnew MyCSharpLibrary())->readValue();

    jbyteArray someJbyteArray = env->NewByteArray((jsize)len);

    env->SetByteArrayRegion(someJbyteArray, 0, len, reinterpret_cast<const jbyte*>(someConstUnsignedChar));

    return someJbyteArray;

}

将 jbyteArray 转换为 const unsigned char*：

JNIEXPORT jboolean JNICALL Java_MyJavaApplication_writeValue(JNIEnv* env, jobject obj, jbyteArray someJbyteArray)

{

    jsize len = env->GetArrayLength(someJbyteArray);

    jbyte* body = env->GetByteArrayElements(someJbyteArray, 0);

    unsigned char* someUnsignedChar = new unsigned char[len];

    for (jint i = 0; i < len; i++)

    {

        someUnsignedChar[i] = (unsigned char)body[i];

    }

    bool result = (gcnew MyCSharpLibrary())->writeValue((const unsigned char*)someUnsignedChar);

    env->ReleaseByteArrayElements(someJbyteArray, body, 0);

    return (jboolean)result;

}

这个对我有用。