过滤器Filter，拦截器Interceptor

1. 过滤器Filter
   1. 快速入门

       

      1. 
      2. 
      3. 
   2. 详情
      1. 
      2. 
      3. 
      4. 
   3. 登录校验-Filter
      1. 
      2. 

      3. package com.itheima.filter;import com.alibaba.fastjson.JSONObject;
         import com.itheima.pojo.Result;
         import com.itheima.utils.JwtUtils;
         import lombok.extern.slf4j.Slf4j;
         import org.springframework.util.StringUtils;import javax.servlet.*;
         import javax.servlet.annotation.WebFilter;
         import javax.servlet.http.HttpServletRequest;
         import javax.servlet.http.HttpServletResponse;
         import java.io.IOException;/*** @author Mr.jia* @version 1.0*/
         @Slf4j
         @WebFilter(urlPatterns = "/*")
         public class LoginCheckFilter implements Filter {@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {HttpServletRequest req = (HttpServletRequest) servletRequest;HttpServletResponse resp = (HttpServletResponse) servletResponse;//1.获取请求urlString url = req.getRequestURI().toString();log.info("请求的url：{}",url);//2.判断请求url中是否包含login，如果包含，说明是登录操作，放行if(url.contains("login")){log.info("登录操作，放行...");filterChain.doFilter(servletRequest,servletResponse);return;}//3.获取请求头中的令牌String jwt = req.getHeader("token");//4.判断令牌是否存在，如果不存在，返回错误结果（未登录）if(!StringUtils.hasLength(jwt)){log.info("请求头token为空，返回登录的信息");Result error = Result.error("NOT_LOGIN");//手动转换  对象---json----->阿里巴巴fastJSONString notLogin = JSONObject.toJSONString(error);resp.getWriter().write(notLogin);return;}//5.解析token，如果解析失败，返回错误结果（未登录）try {JwtUtils.parseJWT(jwt);} catch (Exception e) {//解析失败e.printStackTrace();log.info("解析令牌失败，返回登录的信息");Result error = Result.error("NOT_LOGIN");//手动转换  对象---json----->阿里巴巴fastJSONString notLogin = JSONObject.toJSONString(error);resp.getWriter().write(notLogin);return;}//6.放行log.info("令牌合法，放行");filterChain.doFilter(servletRequest,servletResponse);}
         }
         

2. 拦截器Interceptor
   1. 简介&快速入门
      1. 
      2. 

      3. package com.itheima.interceptor;import org.springframework.stereotype.Component;
         import org.springframework.web.servlet.HandlerInterceptor;
         import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;
         import javax.servlet.http.HttpServletResponse;/*** @author Mr.jia* @version 1.0*/
         @Component
         public class LoginCheckInterceptor implements HandlerInterceptor {@Override //目标资源方法运行前运行，返回true：放行，false：不放行public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {return true;}@Override //目标资源方法运行后运行public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {System.out.println("postHandle");}@Override //视图渲染完毕后运行，最后运行public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {System.out.println("afterCompletion");}
         }
         

         定义拦截器

      4. package com.itheima.config;import com.itheima.interceptor.LoginCheckInterceptor;
         import org.springframework.beans.factory.annotation.Autowired;
         import org.springframework.context.annotation.Configuration;
         import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
         import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;/*** @author Mr.jia* @version 1.0*/
         @Configuration//配置类
         public class WebConfig implements WebMvcConfigurer {@Autowiredprivate LoginCheckInterceptor loginCheckInterceptor;@Overridepublic void addInterceptors(InterceptorRegistry registry){registry.addInterceptor(loginCheckInterceptor).addPathPatterns("/**");}
         }
         

         配置拦截器

   2. 详解（拦截路径，执行流程）
      1. 
      2. 
   3. 登录校验-Interceptor
      1. 
      2. 

      3. /*** @author Mr.jia* @version 1.0*/
         @Slf4j
         @Component
         public class LoginCheckInterceptor implements HandlerInterceptor {@Override //目标资源方法运行前运行，返回true：放行，false：不放行public boolean preHandle(HttpServletRequest servletRequest, HttpServletResponse servletResponse, Object handler) throws Exception {//1.获取请求urlString url = servletRequest.getRequestURI().toString();log.info("请求的url：{}",url);//2.判断请求url中是否包含login，如果包含，说明是登录操作，放行if(url.contains("login")){log.info("登录操作，放行...");return true;}//3.获取请求头中的令牌String jwt = servletRequest.getHeader("token");//4.判断令牌是否存在，如果不存在，返回错误结果（未登录）if(!StringUtils.hasLength(jwt)){log.info("请求头token为空，返回登录的信息");Result error = Result.error("NOT_LOGIN");//手动转换  对象---json----->阿里巴巴fastJSONString notLogin = JSONObject.toJSONString(error);servletResponse.getWriter().write(notLogin);return false;}//5.解析token，如果解析失败，返回错误结果（未登录）try {JwtUtils.parseJWT(jwt);} catch (Exception e) {//解析失败e.printStackTrace();log.info("解析令牌失败，返回登录的信息");Result error = Result.error("NOT_LOGIN");//手动转换  对象---json----->阿里巴巴fastJSONString notLogin = JSONObject.toJSONString(error);servletResponse.getWriter().write(notLogin);return false;}//6.放行log.info("令牌合法，放行");return true;}@Override //目标资源方法运行后运行public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {System.out.println("postHandle");}@Override //视图渲染完毕后运行，最后运行public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {System.out.println("afterCompletion");}
         }