无法使用reactJS中的Express从MySQL数据库用户表中获取所有用户

const express = require('express');
const mysql = require('mysql');

const connection = mysql.createConnection({
  host: 'localhost',
  user: 'root',
  password: 'password',
  database: 'mydatabase'
});

connection.connect((err) => {
  if (err) {
    console.error('Error connecting to MySQL database: ' + err.stack);
    return;
  }
  console.log('Connected to MySQL database as id ' + connection.threadId);
});

app.get('/users', (req, res) => {
  const query = 'SELECT * FROM users';
  connection.query(query, (err, results) => {
    if (err) {
      console.error('Error executing MySQL query: ' + err.stack);
      return res.status(500).json({ error: 'Failed to retrieve users from database' });
    }
    res.json(results);
  });
});

app.listen(3000, () => {
  console.log('Express server is listening on port 3000');
});