java - JSP页面中的内置对象无法调用各自的方法（IDE无提示，并报错）

Answer 1

out is an instance of JspWriter的实例，request是HttpServletRequest and depends on servlet api. If you are using maven application, just add the following dependencies:

<dependency>
  <groupId>javax.servlet</groupId>
  <artifactId>servlet-api</artifactId>
  <version>2.3</version>
</dependency>