yb课堂之用户登陆校验拦截器开发 《十一》

开发对应的登陆拦截器

开发loginInterceptor

• 登陆校验成功放行
• 登陆不成功返回json数据

LoginInterceptor.java

package net.ybclass.online_ybclass.interceptor;

import com.fasterxml.jackson.databind.ObjectMapper;
import io.jsonwebtoken.Claims;
import net.ybclass.online_ybclass.utils.JWTUtils;
import net.ybclass.online_ybclass.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;
import java.io.PrintWriter;

public class LoginInterceptor implements HandlerInterceptor {
    /**
     * 进入到Controller之前的方法
     *
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        try {
            String accesToken = request.getHeader("token");
            if (accesToken == null) {
                accesToken = request.getParameter("token");
            }
            if (StringUtils.isNoneBlank(accesToken)) {
                Claims claims = JWTUtils.checkJWT(accesToken);
                if (claims == null) {
                    sendJsonMessage(response, JsonData.buildError("登陆过期，请重新登陆"));
                    //告诉登陆过期，重新登陆
                    return false;
                }
                Integer id = (Integer) claims.get("id");
                String name = (String) claims.get("name");
                request.setAttribute("user_id", id);
                request.setAttribute("name", name);
                return true;
            }
        } catch (Exception e) {
        }
        //登陆失败
        sendJsonMessage(response, JsonData.buildError("登陆过期，请重新登陆"));
        return false;
    }

    /**
     * 响应json数据给前端
     * @param response
     * @param obj
     */
    public static void sendJsonMessage(HttpServletResponse response, Object obj) {
        try {
            ObjectMapper objectMapper=new ObjectMapper();
            response.setContentType("application/json;charset=utf-8");
            PrintWriter writer=response.getWriter();
            writer.print(objectMapper.writeValueAsString(obj));
            writer.close();
            writer.flush();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @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 {

    }
}