springMvc基于注解登录拦截器

先定义一个拦截器注解

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface LoginRequired {
    
}

在定义一个拦截器

/**
 * 登录拦截器
 */
public class LoginInterceptor extends HandlerInterceptorAdapter {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        if (handler instanceof HandlerMethod) {
            LoginRequired loginRequired = findAnnotation((HandlerMethod) handler, LoginRequired.class);
            //没有声明需要权限,或者声明不验证权限
            if(loginRequired==null){
                return true;
            }else{
                String token=request.getHeader("token");
                if(StringUtils.isEmpty(token)){
                    token=request.getParameter("token");
                }
                //在这里实现自己的权限验证逻辑
                if(!StringUtils.isEmpty(token)){//如果验证成功返回true（这里直接写false来模拟验证失败的处理）
                    return true;
                }else{//如果验证失败
                    response.getWriter().write("您还未登录");
                    return false;
                }       
            }
        }else{
            return true;
        }
    }

    private <T extends Annotation> T findAnnotation(HandlerMethod handler, Class<T> annotationType) {
        T annotation = handler.getBeanType().getAnnotation(annotationType);
        if (annotation != null) return annotation;
        return handler.getMethodAnnotation(annotationType);
    }
}

spring配置

<!-- spring 3.1版本后才支持拦截方法名，需要引入一下配置 -->

<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping" />
<bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor" />
<mvc:annotation-driven />

<mvc:interceptors>
    <mvc:interceptor>
        <mvc:mapping path="/**" />
        <bean class="com.xxx.xxxx.LoginInterceptor"/>
    </mvc:interceptor>
</mvc:interceptors>

 Controller层数直接使用

@ResponseBody
@RequestMapping(value="",method=RequestMethod.GET)
@LoginRequired
protected Map<String,Object> index(){
    return null;
}