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

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

    public static void main(String[] args) {
        CLibrary.INSTANCE.printf("Hello, World\n");
    }
}
// 该源码来自 https://github.com/java-native-access/jna/blob/master/www/GettingStarted.md

<dependency>
    <groupId>net.java.dev.jna</groupId>
    <artifactId>jna</artifactId>
    <version>5.3.1</version>
</dependency>

// c++  需要在 vs 中编译成 dll
int max(int num1, int num2) {
    return num1 > num2 ? num1 : num2;
}

// java
public interface JnaLibrary extends Library {
     // JNA 为 dll 名称
    JnaLibrary INSTANCE = Native.load("JNA", JnaLibrary.class);
    int max(int a, int b);
}

public static void main(String[] args) {
    int max = JnaLibrary.INSTANCE.max(100, 200);
    // out: 200
    System.out.println(max);
}

 // java
public interface JnaLibrary extends Library {
     // JNA 为 dll 名称
    JnaLibrary INSTANCE = Native.load("JNA", JnaLibrary.class);
    void testArray(short[] vals, int len);
}

// c++
void testArray(uint16_t* vals, int len) {
    for (int j = 0; j < len; j++) {
        printf("vals[%d]: %d \n", j, vals[j]);
    }
}

JnaLibrary.INSTANCE.testArray(new short[]{1, 2, 3, 4}, 4);
// out:
vals[0]: 1 
vals[1]: 2 
vals[2]: 3 
vals[3]: 4 

// java
public interface JnaLibrary extends Library {
     // JNA 为 dll 名称
    JnaLibrary INSTANCE = Native.load("JNA", JnaLibrary.class);
    // 实际测试下来 void printUser(User.ByValue user); 也是可以的
    void printUser(User user);
    void printUserRef(User user);

@Structure.FieldOrder({"name", "height", "weight"})
public static class User extends Structure {

public static class UserValue extends User implements Structure.ByValue {

    public UserValue(String name, int height, double weight) {
        super(name, height, weight);
        }
    }

    public User(String name, int height, double weight) {
        this.name = name;
        this.height = height;
        this.weight = weight;
    }

        public String name;
        public int height;
        public double weight;
    }
}

// .h
struct User {
    char* name;
    int height;
    double weight;
};
void printUser(User user);
void printUserRef(User& user);

// cpp
void printUser(User user) {
    printf("printUser user: %s height: %d weight: %.2f \n", user.name, user.height, user.weight);
}
void printUserRef(User& user) {
    printf("printUserRef user: %s height: %d weight: %.2f \n", user.name, user.height, user.weight);
}

JnaLibrary.User.UserValue user1 = new JnaLibrary.User.UserValue("user1", 186, 65.2);
JnaLibrary.INSTANCE.printUserRef(user1);
JnaLibrary.INSTANCE.printUser(user1);
// out:
printUserRef user: user1 height: 186 weight: 65.20 
printUser user: user1 height: 186 weight: 65.20

// java
public interface JnaLibrary extends Library {
    // JNA 为 dll 名称
    JnaLibrary INSTANCE = Native.load("JNA", JnaLibrary.class);
    
    void testStruct(ArrInfo arrInfo);
    
    @Structure.FieldOrder({"vals", "len"})
        public static class ArrInfo extends Structure {
            public Pointer vals;
            public int len;

            public ArrInfo(Pointer vals, int len) {
            this.vals = vals;
            this.len = len;
        }
    }
}

// .h
struct ArrInfo
{
    uint16_t* vals;
    int len;
};
void testStruct(ArrInfo arrInfo);

// cpp
void testStruct(ArrInfo arrInfo) {
    for (int j = 0; j < arrInfo.len; j++) {
        printf("arrInfo[%d]: %d \n", j, arrInfo.vals[j]);
    }
}

// java main test
int len = 3;
int shortSize = Native.getNativeSize(Short.class);
Pointer pointer = new Memory(len * shortSize);
for (int i = 0; i < len; i++) {
    pointer.setShort(shortSize * i, (short) i);
}
JnaLibrary.ArrInfo arrInfo = new JnaLibrary.ArrInfo(pointer, len);
JnaLibrary.INSTANCE.testStruct(arrInfo);
// out
arrInfo[0]: 0 
arrInfo[1]: 1 
arrInfo[2]: 2