javaweb学习中遇到%7BPageContext.request.ContextPath%的问题

${pageContext.request.contextPath}解析成为%7BPageContext.request.ContextPath%
出现这种错误是因为web.xml文件的版本过低

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <welcome-file-list>
      <welcome-file>login.jsp</welcome-file>
    </welcome-file-list>
</web-app>