springboot拦截器@resource注解注入为null解决方案

最新推荐文章于 2025-06-15 19:13:40 发布

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最新推荐文章于 2025-06-15 19:13:40 发布

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本文链接：https://blog.youkuaiyun.com/u011277745/article/details/84388268

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本文详细解析了在Spring框架中，为什么@resource注入会遇到null值的问题，尤其是在interceptor配置中。通过加入@Bean注解和@Configuration类，可以有效解决此问题，确保依赖正确注入。

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为什么@resource注入为null

inteceptor在springcontext之前加载,注入必然是null

解决方案

加入注解@Bean

@Configuration
public class WebMVCInterceptor implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(globalInterceptor())
                .addPathPatterns("/**")
                .excludePathPatterns("/userInfo/jwtUser") //登录页
                .excludePathPatterns("/register") //用户注册
                .excludePathPatterns("/login"); //用户登录
    }

    /**
     * @return globalInterceptor
     */
    @Bean
    public GlobalInterceptor globalInterceptor() {
        return  new GlobalInterceptor();
    }
}

@Component
public class GlobalInterceptor extends HandlerInterceptorAdapter {
    private static Logger logger = LoggerFactory.getLogger(GlobalInterceptor.class);
    @Resource
    private UserRoleService userRoleService;

    /**
     * 调用action之前进行拦截
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        return super.preHandle(request, response, handler);
    }

    /**
     * 从 cookie 中获取 token
     */
    private String getTokenFromCookie(HttpServletRequest request) {
        Cookie[] cookies = Optional.ofNullable(request.getCookies()).orElse(new Cookie[0]); // Optional 强制赋默认值,cookies一定不为 null
        String cookie = Arrays.stream(cookies).filter(item ->
                "X-Auth-Token".equals(item.getName())
        ).findFirst().map(Cookie::getValue).orElse(null);
        return cookie;
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        super.afterCompletion(request, response, handler, ex);
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        super.postHandle(request, response, handler, modelAndView);
    }
}