[英]JNA: Can't create object of structure subclass - Invalid structure field
我正在将C typedef映射到JNA Struct。 下面是C typedef:
typedef struct _GLYCOUNTERS {
unsigned int ulArraySize;
LPGLYCOUNTER lpCounters;
}GLYCOUNTERS, *LPGLYCOUNTERS;
这是我的JNA Structure子类:
public class GlyCounters extends Structure{
public class ByReference extends GlyCounters implements Structure.ByReference {};
public class ByValue extends GlyCounters implements Structure.ByValue {};
public int ulArraySize;
public GlyCounter lpCounters;
@Override
protected List<String> getFieldOrder() {
return Arrays.asList(new String[] { "ulArraySize", "lpCounters"});
}
}
我正在尝试使用代码创建和反对GlyCounters类:
lppCounters = glyTypes.new GlyCounters();
如您所见,我正在另一个类中创建对象,而GlyCounters是另一个类的嵌套类。
这是我收到的错误消息:
Exception in thread "main" java.lang.IllegalArgumentException: Invalid Structure field in class btc_dll.GloryTypeDef$GlyCounters, field name 'lpCounters' (class btc_dll.GloryTypeDef$GlyCounter): Can't instantiate class btc_dll.GloryTypeDef$GlyCounter (java.lang.InstantiationException: btc_dll.GloryTypeDef$GlyCounter)
at com.sun.jna.Structure.validateField(Structure.java:1038)
at com.sun.jna.Structure.validateFields(Structure.java:1048)
at com.sun.jna.Structure.<init>(Structure.java:179)
at com.sun.jna.Structure.<init>(Structure.java:172)
at com.sun.jna.Structure.<init>(Structure.java:159)
at com.sun.jna.Structure.<init>(Structure.java:151)
at btc_dll.GloryTypeDef$GlyCounters.<init>(GloryTypeDef.java:298)
at btc_gui.Btc_gui.main(Btc_gui.java:54)
Java Result: 1
导致该问题的字段是另一个c typedef结构的另一个JNA Structure类。 搜索错误消息后,我尝试将no-args构造函数添加到这两个类中,但错误仍然存在。
有人遇到过类似的问题吗?
当你想类型的字段struct *
你的结构中,您需要使用Structure
标记与接口Structure.ByReference
。
已编辑
最常用的方法是:
public class GlyCounter extends Structure {
public class ByReference extends GlyCounter implements Structure.ByReference {};
// More definition here...
}
public class GlyCounters extends Structure{
public int ulArraySize;
public GlyCounter.ByReference lpCounters;
public GlyCounters(Pointer p) {
super(p);
read();
}
@Override
protected List<String> getFieldOrder() {
return Arrays.asList(new String[] { "ulArraySize", "lpCounters"});
}
}
// To obtain the full array (assuming they're allocated as a block)
GlyCounters gc = new GlyCounters(pointer);
GlyCounter[] counters = gc.lpCounters.toArray(gc.ulArraySize());
字段lpCounters
现在是指针类型,而不是内联的(即,共享封闭struct
的内存)。
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