The El expression in JSP is invalid.

the El expression in JSP is invalid. check the servlet/jsp version used and view the web. if the following content exists at the beginning of XML, it indicates servlet 2.4/jsp 2.0. xmlns = "http://java.sun.com/xml/ns/j2ee" xmlns: xsi = "http://www.w3.org/2001/XMLSchema-instance" xsi: schemalocation = "http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> If the following content exists, Servlet 2.3/jsp 1.2 is used. "-// Sun Microsystems, Inc. // DTD web application 2.3/EN" "http://java.sun.com/dtd/web-app_2_3.dtd"> by default, Servlet 2.3/jsp 1.2 does not support El expressions, whereas servlet 2.4/jsp 2.0 does. In servlet 2.3/jsp 1.2, add the following Code at the beginning of the JSP page. <% @ page iselignored = "false" %> if it is under servlet 2.4/jsp 2.0, check whether iselignored is set to true in the above Code. in XML, whether to set El-ignored in the JSP-property-group label in JSP-config to true. javax. servlet. servletexception: cannot get a connection, pool exhausted the prompt is that the connection pool is full it may be that your code does not properly release the connection object, or the number of concurrent jobs is greater than your maximum limit. Remember to close the resource.