验证登陆，没有登陆，跳转登陆页面
addPathPattern 后跟拦截地址，
**匹配所有
excludePathPatterns 后跟排除拦截地址
package com.stylesmile.config;import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;/*** 拦截器** @author chenye*/
@Configuration
public class WebMvcConfig implements WebMvcConfigurer {/*** 注册拦截器*/@Overridepublic void addInterceptors(InterceptorRegistry registry) {//addPathPattern后跟拦截地址，excludePathPatterns后跟排除拦截地址registry.addInterceptor(new MyInterceptor()).addPathPatterns("/**")//登录页面.excludePathPatterns("/login.do")//注册页面.excludePathPatterns("/register.do")//注册方法.excludePathPatterns("/register.json");}class MyInterceptor implements HandlerInterceptor {/*** 在请求处理之前进行调用（Controller方法调用之前*/@Overridepublic boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {HttpSession session = httpServletRequest.getSession();//获取登录的session信息Object user = session.getAttribute("loginUser");if (user != null) {return true;} else {//未登录自动跳转界面httpServletResponse.sendRedirect(httpServletRequest.getContextPath() + "/login.do");return false;}}/*** 请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后）*/@Overridepublic void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) {System.out.println("postHandle被调用\n");}/*** 在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行（主要是用于进行资源清理工作）*/@Overridepublic void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) {System.out.println("afterCompletion被调用\n");}}
}