在荷兰国立大学,我知道你可以使用<代码>env->DefineClass界定一个类别。 例如,

jclass klass = client->env->DefineClass(nullptr, classLoader, (const jbyte*) classBytes, (jsize) classBytes_size);

同样,我预计还有一项职能,在运行时间界定资源。 通过“资源”,我指的是在杰尔档案中包装的档案,如图像或声音。 但是,我找不到这样做的任何职能。 为什么没有<代码>DefineResource功能? 如果有可能,你如何这样做?

Edit:我是如何向上班机添加一部《URL》。 然而,该方案仍然无法找到我的资源。

Code (jni):

// Creates a File object to the folder, then converts to a URL and then passes it to the ClassLoader.
#define checkNull(x) checkNull_(#x, x)

template <class T>
void checkNull_(const std::string &varName, T x) {
    if (!x) throw std::runtime_error(varName + " is null");
}

void JavaUtils::addClassLoaderURL() {
    jobject classLoader = getClassLoader();
    checkNull(classLoader);
    jclass URLClassLoader = app->getClass("java.net.URLClassLoader");
    checkNull(URLClassLoader);
    jclass File = app->getClass("java.io.File");
    checkNull(File);
    jclass URI = app->getClass("java.net.URI");
    checkNull(URI);
    jmethodID fileConstructor = app->env->GetMethodID(File, "<init>", "(Ljava/lang/String;)V");
    checkNull(fileConstructor);
    jstring classpath = app->env->NewStringUTF("~/classpath");
    checkNull(classpath);
    jobject fileObject = app->env->NewObject(File, fileConstructor, classpath);
    checkNull(fileObject);
    jmethodID toURI = app->env->GetMethodID(File, "toURI", "()Ljava/net/URI;");
    checkNull(toURI);
    jmethodID toURL = app->env->GetMethodID(URI, "toURL", "()Ljava/net/URL;");
    checkNull(toURL);
    jobject URIObject = app->env->CallObjectMethod(fileObject, toURI);
    checkNull(toURL);
    jobject URLObject = app->env->CallObjectMethod(URIObject, toURL);
    checkNull(URLObject);
    jmethodID addURL = app->env->GetMethodID(URLClassLoader, "addURL", "(Ljava/net/URL;)V");
    checkNull(addURL);
    app->env->CallVoidMethod(classLoader, addURL, URLObject);
    if (app->env->ExceptionCheck() == JNI_TRUE) {
        std::cout << "Exception:" << std::endl;
        jthrowable exception = app->env->ExceptionOccurred();
        app->env->ExceptionClear();

        JavaUtils::getInformation(exception);
        return;
    }
    std::cout << "Successfully added path to classloader" << std::endl;
}

The contents of the folder:

 ~
 - classpath
 - - test
 - - - version.txt

否则:

InputStream input = VersionManager.class.getResourceAsStream("/assets/test/version.txt");
Scanner scanner = new Scanner(input); // null pointer exception (because the resource does not exist)