springboot+thymeleaf+jquery和ajax+攔截器實現session狀態保持

原文鏈接：https://blog.csdn.net/qq_36159851/article/details/79887118   （侵刪）

為了保持會話登錄狀態，采用了攔截器來實現session判別

定義自己的攔截器，這個攔截器要實現HandlerInterceptor接口

package server.demo.configure;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import server.demo.entity.User;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
@Component
public class MyInterceptor  implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        //獲取當前的session
        HttpSession session=request.getSession();
        //從session中尋求cur_user變量
        Object obj=session.getAttribute("cur_user");
        //判斷是否存在用戶變量
        //不存在則跳轉到登錄界面
        if(obj==null||!(obj instanceof User)){
          response.sendRedirect("/login");
         }else{
            //存在則再次注入session
            session.setAttribute("cur_user",(User)obj);
            System.out.println(((User) obj).getName()+((User) obj).getPassword());
        }
        return true;// 只有返回true才會繼續向下執行，返回false取消當前請求
    }
    @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 {

    }
}

package server.demo.configure;
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.WebMvcConfigurerAdapter;
import java.util.ArrayList;
import java.util.List;
@Configuration
public class MyWebAppConfigurer extends WebMvcConfigurerAdapter {
    @Autowired
    MyInterceptor myInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // 多個攔截器組成一個攔截器鏈
        // addPathPatterns 用於添加攔截規則
        // excludePathPatterns 用戶排除攔截
        List<String> list=new ArrayList<>();
        list.add("/myPub");
        list.add("/myRec");
        registry.addInterceptor(myInterceptor).addPathPatterns(list);
        super.addInterceptors(registry);
    }
}