刚做Java不久，写个拦截器，以及现在用到的。

需求：登录拦截

原本是想用过滤器实现的，可是发现过滤器会把静态资源文件也过滤【因为我写的是过滤所有请求，会把登录的静态文件给过滤了，可能也能实现，但是没找到，又有点急】，因此用了拦截器实现，因为它可以排除资源请求的拦截

代码：

1：先写一个拦截器类 ，并实现接口  HandlerInterceptor

代码：

package com.jesse.config.interceptor;import com.jesse.util.SessionUtil;
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;/*** 登陆拦截器*/
@Slf4j
public class LoginInterceptor implements HandlerInterceptor {/*** 在请求被处理之前调用** @param request* @param response* @param handler* @return* @throws Exception*/@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {// 检查每个到来的请求对应的session域中是否有登录标识if (SessionUtil.getUserId(request) == null) {// 未登录，重定向到登录页response.sendRedirect("/login.page");return false;}String userName = SessionUtil.getUserId(request);log.info("当前用户已登录，登录的用户名为：{}", userName);return true;}/*** 在请求被处理后，视图渲染之前调用** @param request* @param response* @param handler* @param modelAndView* @throws Exception*/@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {}/*** 在整个请求结束后调用** @param request* @param response* @param handler* @param ex* @throws Exception*/@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {}
}

2：把写好的拦截器注入

代码：

package com.jesse.config.interceptor;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;@Configuration
public class InterceptorConfiguration implements WebMvcConfigurer{@Beanpublic LoginInterceptor loginInterceptor(){return new LoginInterceptor();}@Overridepublic void addInterceptors(InterceptorRegistry registry) {// 注册拦截器//LoginInterceptor loginInterceptor = new LoginInterceptor();InterceptorRegistration loginRegistry = registry.addInterceptor(loginInterceptor());// 拦截路径loginRegistry.addPathPatterns("/**");// 排除路径loginRegistry.excludePathPatterns("/");loginRegistry.excludePathPatterns("/login.page");loginRegistry.excludePathPatterns("/checklogin.page");// 排除资源请求loginRegistry.excludePathPatterns("/assets/**");loginRegistry.excludePathPatterns("/css/**");loginRegistry.excludePathPatterns("/fonts/**");loginRegistry.excludePathPatterns("/image/**");loginRegistry.excludePathPatterns("/js/**");loginRegistry.excludePathPatterns("/qrcode/**");}
}

写的不好勿怪，纯属新手！