extern "C"
 * C/C++ 创建Java对象
 */
JNIEXPORT jlong JNICALL
Java_com_michael_ndk_write_WriteJava_c2JavaClass(JNIEnv *env, jobject instance) {
    //获取Date jclass
    jclass clz = env->FindClass("java/util/Date");
    //获取构造方法id
    jmethodID methodId = env->GetMethodID(clz,"<init>","()V");
    //创建Date对象
    jobject obj = env->NewObject(clz,methodId);
    //获取getTime的方法ID
    jmethodID getTimeId = env->GetMethodID(clz,"getTime","()J");
    //调用getTime方法
    jlong time = env->CallLongMethod(obj,getTimeId);
    LOGI("time = %ldn",time);
    return time;
}