使用spring拦截器与自定义注解进行登录拦截

偏执的太偏执、 2024-02-19 19:36 46阅读 0赞

1.依赖：

<dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
    </dependency>

2.自定义注解：

@Target(ElementType.METHOD)
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    @Inherited
    public @interface LoginCheck {
        boolean check() default false;
    }

3.继承spring的HandlerInterceptor接口实现了里面的的方法：

**在拦截器中需要加入注解的逻辑**

public class LoginInterceptor implements HandlerInterceptor {
        public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse response, Object handler) throws Exception {
    
            System.out.println("进入拦截器");
    
            //1.判断是否存在注解
            if(!(handler instanceof HandlerMethod)){
                return true;
            }
            HandlerMethod method = (HandlerMethod)handler;
            boolean hasLoginAnnotation=method.getMethod().isAnnotationPresent(LoginCheck.class);
            if(!hasLoginAnnotation){
                //不存在LoginRequired注解，则直接通过
                return true;
            }
            LoginCheck loginCheck=method.getMethod().getAnnotation(LoginCheck.class);
            //2.required=false,则无需检查是否登录
            if(!loginCheck.check()){
                return true;
            }
            Object user = httpServletRequest.getSession().getAttribute("user");
            if (user != null) {
                return true;
            }
            //3.登录状态检查,使用response返回指定信息
            //response.getWriter().append("you need login!");
            response.sendRedirect("http://localhost:8081");
            return false;
        }
    
        public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
    
        }
    
        public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
    
        }
    }

4.在springmvc的配置文件中配置拦截器：

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

5.在Controller的方法中加入自定义注解：

@LoginCheck(check = true)
    @RequestMapping("buy")
    public String buy(Integer id, Integer num) {
        System.out.println("进入到buy方法");
        System.out.println("id"+id+"num"+num);
        return "index";
    }

在方法上面加**@LoginCheck(check = true)注解时拦截器会判断用户是否登录，登录则进入方法，否则重定向到登录页面。**