java调用动态库dll详细示例代码

package jni;

public class JniDemo {
    public native static void set(int i);
    public native static int get();
}

javah jni.JniDemo

#include <jni.h> 改为 #include "jni.h"

#include "stdafx.h"
#include "jni_JniDemo.h"

int number = 0;

JNIEXPORT void JNICALL Java_jni_JniDemo_set
(JNIEnv *, jclass, jint i)
{
	number = i;
}

JNIEXPORT jint JNICALL Java_jni_JniDemo_get
(JNIEnv *, jclass)
{
	return number;
}

public class JniDemo {
    static{
        System.loadLibrary("JniDemo");
    }
    public native static void set(int i);
    public native static int get();

    public static void main(String[] args) {
//        System.out.println(System.getProperty("java.library.path"));
        set(100);
        System.out.println(get());
    }
}

<!-- https://mvnrepository.com/artifact/net.java.dev.jna/jna -->
<dependency>
    <groupId>net.java.dev.jna</groupId>
    <artifactId>jna</artifactId>
    <version>5.3.1</version>
</dependency

public interface CLibrary extends Library {
    CLibrary INSTANCE = (CLibrary)
        Native.loadLibrary((Platform.isWindows() ? "msvcrt" : "c"),
                           CLibrary.class);

    void printf(String format, Object... args);
}

struct UserStruct{
long id;
wchar_t* name;
int age;
};

public static class UserStruct extends Structure{
    public NativeLong id;
    public WString name;
    public int age;
    public static class ByReference extends UserStruct
implements Structure.ByReference { }
    public static class ByValue extends UserStruct implements
Structure.ByValue
{ }
}
public void sayUser(UserStruct.ByReference struct);

struct CompanyStruct{
long id;
wchar_t* name;
UserStruct users[100];
int count;
};

public static class CompanyStruct extends Structure{
public NativeLong id;
public WString name;
public UserStruct.ByValue[] users=new UserStruct.ByValue[100];
public int count;
}

CompanyStruct2.ByReference companyStruct2=new CompanyStruct2.ByReference();
companyStruct2.id=new NativeLong(2);
companyStruct2.name=new WString("Yahoo");
companyStruct2.count=10;
UserStruct.ByReference pUserStruct=new
UserStruct.ByReference();
pUserStruct.id=new NativeLong(90);
pUserStruct.age=99;
pUserStruct.name=new WString("杨致远");
// pUserStruct.write();
for(int i=0;i<companyStruct2.count;i++){
companyStruct2.users[i]=pUserStruct;
}
 
TestDll1.INSTANCE.sayCompany2(companyStruct2);