如何通过编程方式查找当前登录的用户ID？

// 使用localStorage存储用户ID
localStorage.setItem('userID', '123456');

// 使用sessionStorage存储用户ID
sessionStorage.setItem('userID', '123456');

// 使用Cookies存储用户ID
document.cookie = 'userID=123456';

from flask import request

@app.route('/user')
def get_user_id():
    user_id = request.cookies.get('userID')
    return user_id

app.get('/user', (req, res) => {
    const user_id = req.cookies.userID;
    res.send(user_id);
});

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;

@GetMapping("/user")
public String getUserId(HttpServletRequest request) {
    Cookie[] cookies = request.getCookies();
    if (cookies != null) {
        for (Cookie cookie : cookies) {
            if (cookie.getName().equals("userID")) {
                return cookie.getValue();
            }
        }
    }
    return null;
}