SpringBoot配置攔截器

1.創建一個自定義攔截器，實現HandlerInterceptor

package com.hmdp.utils;
import com.hmdp.dto.UserDTO;
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;
/**
 * 攔截器
 */
public class LoginInterceptor implements HandlerInterceptor {
    /**
     * 前置攔截器 --- 進入controller之前進行登錄校驗
     *
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //1.獲取session
        HttpSession session = request.getSession();
        //2.獲取session中的用戶
        Object user = session.getAttribute("user");
        //3.判斷用戶是否存在
        if (user==null){
            //4.不存在，攔截 返回401未授權
            response.setStatus(401);
            return false;
        }
        //5.存在，保存用戶到ThreadLocal
        UserHolder.saveUser((UserDTO) user);
        //6.放行
        return true;
    }
    /**
     * 增強攔截器--空過
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    }
    /**
     *  后置攔截器 --- 用戶業務執行完畢，銷毀對應的用戶信息
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        UserHolder.removeUser();
    }
}

2.調用配置類攔截器

package com.hmdp.config;
import com.hmdp.utils.LoginInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class MvcConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //添加攔截器，、
        //配置不攔截的路徑
        registry.addInterceptor(new LoginInterceptor()).excludePathPatterns(
                "/user/code",
                "/user/login",
                "/blog.hot",
                "/shop/**",
                "/shop-type/**",
                "/voucher/**"
        );
    }
}