java SpringBoot（七）拦截器handler使用

妖狐艹你老母 2022-11-12 04:22 103阅读 0赞

**拦截器的作用主要是防止未登录情况下访问我们的静态页面以及静态资源**

**主要步骤：**

* 1、编写一个拦截器实现HandlerInterceptor接口
    * 2、注册拦截器到容易中（实现addInterceptors）
    * 3、指定拦截规则

**1、编写我们的拦截器，新建拦截器文件夹，编写拦截器类**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNzcxNTY3_size_16_color_FFFFFF_t_70][]

**代码：**

package com.example.demo.interceptor;
    
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.web.servlet.HandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    
    /**
     * 登录检查
     * 1、配置拦截器要拦截哪些请求
     * 2、把这些配置放在容器里
     */
    @Slf4j
    public class LoginInterceptor implements HandlerInterceptor {
    
        /**
         * 目标方法执行之前
         * @param request
         * @param response
         * @param handler
         * @return
         * @throws Exception
         */
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
            //获取当前的请求路径
            String requestURI = request.getRequestURI();
            //打印日志
            log.info("拦截的请求路径是{}",request);
            //登录检查逻辑
            HttpSession session = request.getSession();
            Object loginUser = session.getAttribute("loginUser");
            if (loginUser!=null){
                //登录成功
                return true;
            }
            //拦截住，未登录，跳转到登录页
    //        session.setAttribute("msg","请先登录");
    //        response.sendRedirect("/");
            request.setAttribute("msg","请先登录");
            request.getRequestDispatcher("/").forward(request,response);
            return false;
        }
    
        /**
         * 方法目标执行之后
         * @param request
         * @param response
         * @param handler
         * @param modelAndView
         * @throws Exception
         */
        @Override
        public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    
        }
    
        @Override
        public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    
        }
    }

**2、注册我们的拦截器 **

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNzcxNTY3_size_16_color_FFFFFF_t_70 1][]

**代码：**

package com.example.demo.config;
    
    import com.example.demo.interceptor.LoginInterceptor;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
    
    /**
     * 1、编写一个拦截器实现HandlerInterceptor接口
     * 2、注册拦截器到容易中（实现addInterceptors）
     * 3、指定拦截规则
     */
    @Configuration
    public class AdminWebConfig implements WebMvcConfigurer {
    
        @Override
        //配置拦截器
        public void addInterceptors(InterceptorRegistry registry) {
            //添加拦截器
            //拦截/**全部，放行/ /login
            registry.addInterceptor(new LoginInterceptor()).addPathPatterns("/**") //所有请求都会被拦截，包括静态资源
                    .excludePathPatterns("/","/login","/css/**","/fonts/**","/images/**","/js/**"); //放行的请求
        }
    }

**注册成功即可访问测试拦截器~**

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