Many people find System.out.println () is not something that can be output in the jsp page, it is because the System.out.println () is output to the console
We need to use out.println () and out.print () to output something to the jsp page, but may appear red phenomenon pirntln, it is because you have not added tomcat with dependence.
As follows:
Top right, click the + sign to add library, you can select tomcat
