HandlerInterceptor+ThreadLocal实现用户登录全局验证

某些前端页面我们需要登陆之后才能看到数据。但是涉及的页面非常多，如果每个请求都做用户验证，写到代码service层就非常臃肿。

通过拦截所有请求，对有需要的方法，加上@LoginUser

注解，通过判断标注过的注解方法，则需要能过token获取登陆信息。

第一步：拦截所有请求，实现HandlerInterceptor接口，

@Configuration
public class UserLoginInterceptor implements HandlerInterceptor {


    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

    }

    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {

    }

    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {
    }

}

第二步：在preHandle 中获取request中，对应的token信息，通过token获取登陆信息（因为登陆过，所以会保存到redis中），获取登陆信息，判断@LoginUser注解过的方法，统一拦截未登录的请求。

Threadlocal保存对应token对应的的登陆信息，在service可以直接获取登陆的用户信息。
ContextHolderUtil.setLoginUser(userLoginVo);

private static final ThreadLocal LOGIN_USER = new ThreadLocal<>();
public static void setLoginUser(UserLoginVo userLoginVo) {
    LOGIN_USER.set(userLoginVo);
}

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 解析用户
        String token = request.getParameter("access_token");
        if (StringUtils.isNotBlank(token)) {
            try {
                UserLoginVo userLoginVo = userService.convertToken2User(token);
                ContextHolderUtil.setLoginUser(userLoginVo);
                LOGGER.info("UserLogin#setLoginUser success token[{}] userLoginVo:[{}]", token, userLoginVo);
            } catch (Exception e) {
                LOGGER.error("preHandle#setLoginUser", e);
            }
        } else {
            LOGGER.info("UserLogin#setLoginUser token is blank");
        }

        HandlerMethod handlerMethod = (HandlerMethod) handler;
        LoginUser o = handlerMethod.getMethodAnnotation(LoginUser.class);
        if (Objects.nonNull(o) && Objects.isNull(userService.getLoginUser())) {
            ContextHolderUtil.removeAll();
            LOGGER.warn("UserLogin#setLoginUser url need login but token is [{}]", token);
            throw new BusinessException(ResponseUtil.unlogin());
        }
        return true;
    }


    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {
        ContextHolderUtil.removeAll();
        LOGGER.info("UserLogin#removeLoginUser success");
    }

备注：ThreadLocal妙用

ThreadLocal：可保存对应Controller中对应的语言国际化信息，ip信息，服务消耗时间time等信息

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 设置语言
        String locale = request.getParameter("lang");
        if (StringUtils.isBlank(locale)) {
            locale = LocaleUtil.zh;
        }
        ContextHolderUtil.setClientLocale(locale);
        ContextHolderUtil.setClientIp(request.getParameter("client_ip"));

        ......
        ......

        return ture;
}