Node.js try 使用Express和连接池将数据插入MySQL数据库时出现拒绝访问错误

在try 使用Express和连接池将新数据插入MySQL数据库时，我遇到了一个问题.每次我在我的网站上单击提交按钮时，我都会收到以下错误消息: Error: Access denied for user ''@'localhost' (using password: NO)个

下面是来self 的Node.js应用程序server.js的相关代码片段:

import express from "express";
import cors from "cors";
import dotenv from "dotenv";
import * as mysql from "mysql2";
dotenv.config({ path: "backend/server/.env" });
import { saveNewBirthday } from "./database/saveNewBirthday.js";

const server = express();
const corsOption = {
  origin: "http://localhost:3000",
};

const port = 8000;
server.use(cors(corsOption));
server.use(express.json());
const pool = mysql.createPool({
  host: process.env.DB_HOST,
  user: process.env.DB_USER,
  password: process.env.DB_PASSWORD,
  database: process.env.DB_NAME,
});

server.post("/new_birthday", (req, res) => {
  const requestBody = req.body;
  const date = requestBody.date;
  const name = requestBody.name;
  const memo = requestBody.memo;
  const sendEmail = requestBody.sendEmail;
  
  saveNewBirthday(pool, date, name, memo, sendEmail) //
    .then((result) => {
      console.log(result);
    })
    .catch((reject) => {
      console.log(reject);
    });
});
server.listen(port, () => {
  console.log("listening on", port);
})

这是来自saveNewBirthday.js的saveNewBirthday函数代码:

export function saveNewBirthday(pool, date, name, memo, sendEmail) {
 return new Promise((resolve, reject) => {
   pool.getConnection((error, connection) => {
     if (!error) {
       const query =
         "INSERT INTO birthdays (BirthDate, BirthName, BirthMemo, SendEmail) VALUES (?, ?, ?, ?)";
       const data = [date, name, memo, sendEmail];
       connection.query(query, data, (err) => {
         if (!err) {
           connection.release();
           resolve({
             fail: false,
             where: "",
             errorMessage: "",
           });
         } else {
           reject({
             fail: true,
             where: "insert",
             errorMessage: `${err}`,
           });
         }
       });
     } else {
       reject({
         fail: true,
         where: "getConnection",
         errorMessage: `${error}`,
       });
     }
   });
 });
}

我已经验证了process.env.DB_PASSWORD已正确加载，并且MySQL用户具有所有必要的权限.尽管进行了这些判断，访问被拒绝错误仍然存在.

有人能帮我理解为什么会遇到这个问题并建议可能的解决方案吗？感谢您的真知灼见或指导.