java - JNI : NoSuchFieldError

Question

输出:javap -s SomeClass

public org.someapp.SomeClass$_data data;
  Signature: Lorg/someapp/SomeClass$_data;

Java中SomeClass的定义:

class SomeClass
{
    private class _data {
        byte[] something = new byte[1234];
    }

    public _data data;
}

Java中native函数的定义:

public static native int NativeFunction(SomeClass something);

Java 实现:

SomeClass x = new SomeClass();
NativeInterface.NativeFunction(x);

但是，当执行下面的代码时:

JNIEXPORT jint JNICALL Java_org_someapp_NativeInterface_NativeFunction(JNIEnv* env, jobject obj, jobject someobject) {
    jclass some_class = (*env)->GetObjectClass(env, someobject);
    jfieldID data = (*env)->GetFieldID(env, some_class, "data", "Lorg/someapp/SomeClass$_data"); 
}

Java 在 GetFieldID 调用中抛出“NoSuchFieldError;: data”异常。我不明白。签名很好(直接从 javap 复制)。

请注意，为更简单的变量获取字段 ID，例如无符号短整型(带有签名“S”)就可以正常工作。

Answer 1

我觉得 "Lorg/someapp/SomeClass$_data" 应该是 "Lorg/someapp/SomeClass$_data;"。注意分号。