jna调用c++的dll

import java.util.ArrayList;
import java.util.List;

import com.sun.jna.Structure;

public class MyStructure extends Structure {

    public static class ByReference extends MyStructure implements Structure.ByReference {}

    public static class ByValue extends MyStructure implements Structure.ByValue {}

    public float outputSim;

    @Override
    protected List<String> getFieldOrder() {
        List<String> Field = new ArrayList<String>();
        Field.add("outputSim");
        return Field;
    }

}

import com.sun.jna.Library;
import com.sun.jna.Native;

public interface className extends Library {

className INSTANCE = (className) Native.loadLibrary(dll路径,    className.class);

int interfaceName(String A, String B, MyStructure.ByReference ref);
}

ByReference ref = new ByReference();
Integer state = className.INSTANCE.interfaceName(A, B, ref);

//ref.（c++的接口的输出结果参数名称），获取结果