Cannot resolve method 'println(java.lang.String)'

jsp文件中println爆红

<%
  int sum = 0;
  for (int i = 1; i <=100 ; i++) {
    sum+=i;
  }
  out.println("<h1>Sum="+sum+"</h1>");
%>

解决方法

File-----> Invalidate Caches...------>Clear downloaded------>Invalidate and Restart

之后等待重启即可