jna中传递结构体数组有关问题

jna中传递结构体数组问题
问题描述：在java程序中传递单个结构体时，程序正常； 但是传递的参数为结构体数组时，程序出错。
提示： java.lang.IllegalArgumentException: Structure array elements must use contiguous memory (bad backing address at Structure array index 1)

具体代码如下：
dlljna2.h

C/C++ code

#define MYLIBAPI  extern   "C"     __declspec( dllexport ) #define CLIENT_INPUT_SIZE 4struct UserStruct{   long id;   wchar_t*  name;   int age;};MYLIBAPI void sayUser(UserStruct* pUserStruct);

dlljna2.cpp

C/C++ code

#include "stdafx.h"#include "dlljna2.h"#include "iostream"void sayUser(UserStruct* pUserStruct){   std::wcout.imbue(std::locale("chs"));   std::wcout<<L"ID:"<<pUserStruct->id<<std::endl;   std::wcout<<L"姓名："<<pUserStruct->name<<std::endl;   std::wcout<<L"年龄："<<pUserStruct->age<<std::endl;}

TestDll1Service.java

Java code

package test.cn;import test.cn.TestDll1Service.TestDll1.UserStruct;import com.sun.jna.Library;import com.sun.jna.NativeLong;import com.sun.jna.Structure;import com.sun.jna.Native;import com.sun.jna.WString;public class TestDll1Service {    public final static  int CLIENT_INPUT_SIZE = 4;    public interface TestDll1 extends Library {        TestDll1 INSTANCE = (TestDll1) Native.loadLibrary("dlljna2",                TestDll1.class);        public void say(WString value);        public static class UserStruct extends Structure {            public NativeLong id;            public WString name;            public int age;        }        public void sayUser(UserStruct struct);    }    public TestDll1Service() {    }    public static void main(String[] args) {        UserStruct userStruct = new UserStruct();        userStruct.id = new NativeLong(100);        userStruct.age = 30;        userStruct.name = new WString("沈东良");        TestDll1.INSTANCE.sayUser(userStruct);    }}

此时java程序运行正常


但是我稍作改动dlljna2.cpp文件改为

C/C++ code

#include "stdafx.h"#include "dlljna2.h"#include "iostream"void sayUser(UserStruct* pUserStruct){   std::wcout.imbue(std::locale("chs"));  for(int i = 0; i < CLIENT_INPUT_SIZE; i++)   {       std::wcout<<L"ID:"<<pUserStruct[i].id<<std::endl;   std::wcout<<L"姓名："<<pUserStruct[i].name<<std::endl;    std::wcout<<L"年龄："<<pUserStruct[i].age<<std::endl;}

然后将TestDll1Service.java代码改为

Java code

package test.cn;import test.cn.TestDll1Service.TestDll1.UserStruct;import com.sun.jna.Library;import com.sun.jna.NativeLong;import com.sun.jna.Structure;import com.sun.jna.Native;import com.sun.jna.WString;public class TestDll1Service {    public final static  int CLIENT_INPUT_SIZE = 4;    public interface TestDll1 extends Library {        TestDll1 INSTANCE = (TestDll1) Native.loadLibrary("dlljna2",                TestDll1.class);        public void say(WString value);        public static class UserStruct extends Structure {            public NativeLong id;            public WString name;            public int age;        }        public void sayUser(UserStruct[] struct);    }    public TestDll1Service() {    }    public static void main(String[] args) {        UserStruct[] userStructs = new UserStruct[CLIENT_INPUT_SIZE];                for(int i = 0; i < CLIENT_INPUT_SIZE; i++)        {            userStructs[i] =new UserStruct();            userStructs[i].id = new NativeLong(100);            userStructs[i].age = 30;            userStructs[i].name = new WString("沈东良");        }        TestDll1.INSTANCE.sayUser(userStructs);    }} 
 

就会报错：java.lang.IllegalArgumentException: Structure array elements must use contiguous memory (bad backing address at Structure array index 1)

请问如何解决这个问题？谢谢！


[解决办法]
像这种情况，可以考虑改一下接口，java端用字节数组发送，C端用字节数组接收，然后C再通过memcpy的方式，把字节数组内容复制到结构体中还原结构体。

查看更多 下一篇