前置知识SpringBoot配置拦截器基于HandlerInterceptor接口实现，关键三个方法
preHandle()执行目标之前postHandle()执行目标之后afterCompletion()目标执行完后参数
拦截器实现
1.编写一个拦截器实现HandlerInterceptor接口
package com.b0.admin.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;/*** 实现功能登录检查* 1.配置拦截器要拦截那些请求* 2.把这些配置放在容器中*/@Slf4jpublic class LoginInterceptor implements HandlerInterceptor {/*** 目标方法执行之前*/@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {String requestURI = request.getRequestURI();log.info("拦截的请求路径是{}",requestURI);//登录检查逻辑HttpSession session = request.getSession();//判断session中是否存在loginUser，登录成功的用户会在session中加入loginUser对象Object loginUser = session.getAttribute("loginUser");if (loginUser!=null){return true;}//拦截请求。未登录，跳转到登录页//response.sendRedirect("/");//使用重定向传不过去msg信息，需要修改为请求转发request.setAttribute("msg","请先登录！");request.getRequestDispatcher("/").forward(request,response);return false;}/*** 目标方法执行之后*/@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {log.info("postHandle执行{}",modelAndView);}/*** 目标方法页面渲染之后*/@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {log.info("afterCompletion执行异常{}",ex);}}
2.拦截器注册到容器中，并指定拦截规则【如果拦截所有，静态资源也会被拦截】
通过编写配置类实现WebMvcConfigurer类重写addInterceptors()方法
package com.b0.admin.config;import com.b0.admin.interceptor.LoginInterceptor;import org.springframework.context.annotation.Configuration;import org.springframework.web.servlet.config.annotation.InterceptorRegistry;import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;@Configurationpublic class AdminWebConfig implements WebMvcConfigurer {@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(new LoginInterceptor()).addPathPatterns("/**")// /** 表示拦截所有请求,静态资源也会被拦截.excludePathPatterns("/","/login","/css/**","/fonts/**","/images/**","/js/**");//指定放行的请求}}
