微服务登录拦截器开发和ThreadLocal原理+经典应用

    /**
     * 响应json数据给前端
     *
     * @param response
     * @param obj
     */
    public static void sendJsonMessage(HttpServletResponse response, Object obj) {

        ObjectMapper objectMapper = new ObjectMapper();
        response.setContentType("application/json; charset=utf-8");

        try (PrintWriter writer = response.getWriter()) {
            writer.print(objectMapper.writeValueAsString(obj));

            response.flushBuffer();

        } catch (IOException e) {
            log.warn("响应json数据给前端异常:{}",e);
        }


    }

import io.jsonwebtoken.Claims;
import lombok.extern.slf4j.Slf4j;
import net.xdclass.enums.BizCodeEnum;
import net.xdclass.model.LoginUser;

import net.xdclass.utils.CommonUtil;
import net.xdclass.utils.JWTUtil;
import net.xdclass.utils.JsonData;
import org.apache.commons.lang3.StringUtils;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;



@Slf4j
public class LoginInterceptor implements HandlerInterceptor {


    public static ThreadLocal<LoginUser> threadLocal = new ThreadLocal<>();


    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        String accessToken = request.getHeader("token");
        if(accessToken == null) {
            accessToken = request.getParameter("token");
        }

        if(StringUtils.isNotBlank(accessToken)){
            //不为空
            Claims claims = JWTUtil.checkJWT(accessToken);
            if(claims == null){
                //未登录
                CommonUtil.sendJsonMessage(response,JsonData.buildResult(BizCodeEnum.ACCOUNT_UNLOGIN));
                return false;
            }

            long userId = Long.valueOf(claims.get("id").toString());
            String headImg = (String)claims.get("head_img");
            String name = (String)claims.get("name");
            String mail = (String)claims.get("mail");


            LoginUser loginUser = new LoginUser();
            loginUser.setName(name);
            loginUser.setHeadImg(headImg);
            loginUser.setId(userId);
            loginUser.setMail(mail);

            //通过attribute传递用户信息
            //request.setAttribute("loginUser",loginUser);

            //通过threadLocal传递用户登录信息

            threadLocal.set(loginUser);

            return true;

        }


        CommonUtil.sendJsonMessage(response,JsonData.buildResult(BizCodeEnum.ACCOUNT_UNLOGIN));
        return false;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    threadLocal.remove();
    }
}