登录拦截器+ThreadLocal实现用户信息存储

/**
 * 登录拦截器
 */
public class LoginInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 在请求处理之前进行调用，返回true则继续向下执行，返回false则中断请求
        String loginId = request.getHeader("loginId");
        if (StringUtils.isNotBlank(loginId)) {
            // 如果请求头中包含loginId，将其设置到LoginContextHolder中
            LoginContextHolder.set("loginId", loginId);
        }
        return true;
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        // 在整个请求结束之后被调用，也就是在DispatcherServlet渲染了对应的视图之后执行，主要是做清理工作
        // 移除LoginContextHolder中的loginId
        LoginContextHolder.remove();
    }
}

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public class LoginContextHolder {

    // 使用InheritableThreadLocal来存储线程局部变量，确保子线程可以继承父线程的值
    private static final InheritableThreadLocal<Map<String,Object>> THREAD_LOCAL =
            new InheritableThreadLocal<Map<String, Object>>();

    /**
     * 设置线程局部变量的值
     * @param key 键
     * @param val 值
     */
    public static void set(String key,Object val){
        Map<String,Object> map = getThreadLocalMap();
        map.put(key,val);
    }

    /**
     * 获取线程局部变量的值
     * @param key 键
     * @return 值
     */
    public static Object get(String key){
        Map<String, Object> threadLocalMap = getThreadLocalMap();
        return threadLocalMap.get(key);
    }

    /**
     * 移除线程局部变量
     */
    public static void remove(){
        THREAD_LOCAL.remove();
    }

    /**
     * 获取登录ID
     * @return 登录ID
     */
    public static String getLoginId(){
        return String.valueOf(getThreadLocalMap().get("loginId"));
    }

    /**
     * 获取线程局部变量的Map对象
     * @return Map对象
     */
    public static Map<String,Object> getThreadLocalMap(){
        Map<String, Object> map = THREAD_LOCAL.get();

        if(Objects.isNull(map)){
            map = new ConcurrentHashMap<>();
            THREAD_LOCAL.set(map);
        }
        return map;
    }
}

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