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 {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) servletRequest;
        HttpServletResponse resp = (HttpServletResponse) servletResponse;
        //1.获取请求url
        String 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fastJSON
            String 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fastJSON
            String notLogin = JSONObject.toJSONString(error);
            resp.getWriter().write(notLogin);
            return;
        }
        //6.放行
        log.info("令牌合法，放行");
        filterChain.doFilter(servletRequest,servletResponse);
    }
}

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

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 {

    @Autowired
    private LoginCheckInterceptor loginCheckInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry){
        registry.addInterceptor(loginCheckInterceptor).addPathPatterns("/**");
    }
}

配置拦截器

/**
 * @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url
        String 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fastJSON
            String 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fastJSON
            String 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");
    }
}