springboot调用C#封装的DLL文件中函数的实现那

using Infrastructure;
using System.Runtime.InteropServices;
using System.Text;
using System.Text.Json;

namespace PH.Resistance;

/// <summary>
/// 预热器 阻力计算
/// </summary>
public class PHResistance
{
    private double? C1_outlet_YP01; //C1出口压力A
    private double? C1_outlet_YP02; //C2出口压力B
    private double? C2_outlet_YP01; //C2出口压力A
    private double? C2_outlet_YP02; //C2出口压力B
    private double? C3_outlet_YP01; //C3出口压力A
    private double? C3_outlet_YP02; //C3出口压力B
    //private decimal C4_outlet_YP01; //C4出口压力A
    //private decimal C4_outlet_YP02; //C4出口压力B
    //private decimal C5_outlet_YP01; //C5出口压力A
    //private decimal C5_outlet_YP02; //C5出口压力B

    /// <summary>
    ///
    /// </summary>
    /// <param name="c1_outlet_yp01"></param>
    /// <param name="c1_outlet_yp02"></param>
    /// <param name="c2_outlet_yp01"></param>
    /// <param name="c2_outlet_yp02"></param>
    /// <param name="c3_outlet_yp01"></param>
    /// <param name="c3_outlet_yp02"></param>
    public PHResistance(
        double? c1_outlet_yp01 = null, double? c1_outlet_yp02 = null,
        double? c2_outlet_yp01 = null, double? c2_outlet_yp02 = null,
        double? c3_outlet_yp01 = null, double? c3_outlet_yp02 = null
    ){
        C1_outlet_YP01 = c1_outlet_yp01;
        C1_outlet_YP02 = c1_outlet_yp02;
        C2_outlet_YP01 = c2_outlet_yp01;
        C2_outlet_YP02 = c2_outlet_yp02;
        C3_outlet_YP01 = c3_outlet_yp01;
        C3_outlet_YP02 = c3_outlet_yp02;
    }

    /// <summary>
    /// 计算预热器阻力值
    /// </summary>
    /// <returns></returns>
    public Response CalcPHResistance()
    {
        if (!C1_outlet_YP01.HasValue) return Response.Error("C1旋风筒（A列）阻力值无效", "");
        if (!C1_outlet_YP02.HasValue) return Response.Error("C1旋风筒（B列）阻力值无效", "");
        if (!C2_outlet_YP01.HasValue) return Response.Error("C2旋风筒（A列）阻力值无效", "");
        if (!C2_outlet_YP02.HasValue) return Response.Error("C2旋风筒（B列）阻力值无效", "");
        if (!C3_outlet_YP01.HasValue) return Response.Error("C3旋风筒（A列）阻力值无效", "");
        if (!C3_outlet_YP02.HasValue) return Response.Error("C3旋风筒（B列）阻力值无效", "");

        try
        {
            bool res = true;
            StringBuilder strB = new();

            //C1旋风筒
            if (Math.Abs(C1_outlet_YP01.Value) > 6000)
            {
                strB.Append("C1旋风筒（A列）阻力高");
                res = false;
            }

            if (Math.Abs(C1_outlet_YP02.Value) > 6000)
            {
                strB.Append("C1旋风筒（B列）阻力高！");
                res = false;
            }

            //C2旋风筒
            if (Math.Abs(C2_outlet_YP01.Value) > 5000)
            {
                strB.Append("C2旋风筒（A列）阻力高！");
                res = false;
            }

            if (Math.Abs(C2_outlet_YP02.Value) > 5000)
            {
                strB.Append("C2旋风筒（B列）阻力高！");
                res = false;
            }

            //C3旋风筒
            if (Math.Abs(C3_outlet_YP01.Value) > 4200)
            {
                strB.Append("C3旋风筒（A列）阻力高！");
                res = false;
            }

            if (Math.Abs(C3_outlet_YP02.Value) > 4200)
            {
                strB.Append("C3旋风筒（B列）阻力高！");
                res = false;
            }

            if (res)
            {
                return Response.Ok("预热器阻力正常", "");
            }
            else
            {
                return Response.Error("预热器阻力高", strB.ToString());
            }
        }
        catch (Exception ex)
        {
            throw;
        }
    }

    /// <summary>
    ///
    /// </summary>
    public static class NativeExports
    {
        [UnmanagedCallersOnly(EntryPoint = "CreatePHResistance")]
        public static IntPtr CreatePHResistance(
            double a, double b, double c,
            double d, double e, double f)
        {
            var instance = new PHResistance(a, b, c, d, e, f);
            GCHandle handle = GCHandle.Alloc(instance);
            return (IntPtr)handle;
        }

        [UnmanagedCallersOnly(EntryPoint = "CalcPHResistance")]
        public static IntPtr CalcPHResistance(IntPtr instancePtr)
        {
            var handle = (GCHandle)instancePtr;
            var instance = (PHResistance)handle.Target!;
            var res = instance?.CalcPHResistance();
            // 将字符串转换为 UTF-8 字节数组
            byte[] utf8Bytes = Encoding.UTF8.GetBytes(res.ToString());
            // 将字节数组复制到非托管内存并返回指针
            IntPtr unmanagedPointer = Marshal.AllocHGlobal(utf8Bytes.Length);
            Marshal.Copy(utf8Bytes, 0, unmanagedPointer, utf8Bytes.Length);
            return unmanagedPointer;
        }

        [UnmanagedCallersOnly(EntryPoint = "DeletePHResistance")]
        public static void DeletePHResistance(IntPtr instancePtr)
        {
            var handle = (GCHandle)instancePtr;
            handle.Free();
        }
    }
}

<dependency>
            <groupId>net.java.dev.jna</groupId>
            <artifactId>jna</artifactId>
            <version>4.1.0</version>
        </dependency>

public interface IIotService extends Library {
    IIotService INSTANCE=(IIotService) Native.loadLibrary("PH.Resistance.dll", IIotService.class);

    //构造函数
    Pointer CreatePHResistance(double c1_outlet_yp01, double c1_outlet_yp02,
                         double c2_outlet_yp01, double c2_outlet_yp02,
                         double c3_outlet_yp01, double c3_outlet_yp02);
    //具体方法
    Pointer CalcPHResistance(Pointer pointer);
    //释放对象
    void DeletePHResistance(Pointer pointer);
}

@GetMapping("/testCalcPHResistance")
    public String testCalcPHResistance(){
        //初始化构造函数
        Pointer constructPointer=IIotService.INSTANCE.CreatePHResistance(10.0,2.0,3.0,4.0,5.0,6.0);
        //执行逻辑函数
        Pointer pointerResult=IIotService.INSTANCE.CalcPHResistance(constructPointer);
        //获取结果
        String result=pointerResult.getString(0);
        //释放构造函数的对象
        IIotService.INSTANCE.DeletePHResistance(constructPointer);
        return result;
    }