java中使用jna对应unsigned int类型的数值问题

Question

如题,我在java中使用了jna调用dll,dll中有个结构体有一些unsigned int类型参数,在java中我尝试用int接收,在我的demo.dll中调用可以获取正确的值
代码如下:
demo.dll 的头文件

#pragma once
#define DECLSPEC extern "C" _declspec(dllexport)


typedef struct demoStruct
{
    unsigned int flag;
    
}demoStruct;

typedef struct demoStruct2
{
    demoStruct * demoStruct;

}demoStruct2;


DECLSPEC unsigned int getData();

DECLSPEC  demoStruct2 * getStruct();

demo.dll的 源文件:

#include "pch.h"
#include "demo.h"
#include <stdio.h>
unsigned int getData() {
    unsigned int a = 43534;
    return a;
}

demoStruct2 * getStruct() {
    struct demoStruct * strut;
    strut = new demoStruct();
    unsigned int a = 43534;
    strut->flag = a;

    struct demoStruct2 *strut2;
    strut2 = new demoStruct2();
    strut2->demoStruct = strut;
    return strut2;
}

然而在实际项目中使用int获取到的值是不正确的
实际项目dll 部分源码:

/*所有获取信息的结构体*/
typedef struct SqSdpcInfo
{
    char *fileName;
    SqPicHead *picHead;
}SqSdpcInfo;

typedef struct SqPicHead
{
    unsigned int flag; 
}SqPicHead;

java中对应结构体:

public class SqSdpcInfo extends Structure {
    public String fileName;
    public SqPicHead.ByReference picHead;
    public SqSdpcInfo() {
        super();
    }
    protected List<String> getFieldOrder() {
        return Arrays.asList("fileName", "picHead");
    }

    public SqSdpcInfo(Pointer peer) {
        super(peer);
    }
    public static class ByReference extends SqSdpcInfo implements Structure.ByReference {
        
    };
    public static class ByValue extends SqSdpcInfo implements Structure.ByValue {
        
    };

public class SqPicHead extends Structure {


    public int flag;
    
    public SqPicHead() {
        super();
    }
    protected List<String> getFieldOrder() {
        return Arrays.asList("flag");
    }
    public SqPicHead(Pointer peer) {
        super(peer);
    }
    public static class ByReference extends SqPicHead implements Structure.ByReference {

    };
    public static class ByValue extends SqPicHead implements Structure.ByValue {
        
    };

以下是java调用dll代码

  SqSdpcInfo.ByReference sqOpenSdpc = DecodeSdpc.Instance.SqOpenSdpc(filepath);

总结:demo中使用int可以正确的获取dll中 unsigned int 对应的值,而正式项目中int获取的数值不对

Answer 1

C++与Java通信，要进行高低位转换。