Idea导入项目出现Cannot resolve symbol 'HttpServlet'错误:
eclipse导入项目此类报错参考:https://blog.csdn.net/lihua5419/article/details/94742369
1、File->Settings->Application Servers->+ Tomcat Server->选择tomcat->OK
2、右键项目选择Open Module Setting->
选择Global Libraries->+->Java->
进入刚才设置的Tomcat目录选择lib下的servlet-api.jar,