解决web.xml中UTF-8报错。错误提示：cvc-complex-type.2.4.a:Invalidcontentwasfoundstartingwithelement'page-encoding'.Oneof'{"http://java.sun.com/xml/ns/javaee":include-prelude,"http://java.sun.com/xml/ns/javaee":include-coda,"http://java.sun.com/