Tomcat startup hint cannot find the declaration of element ' Web-app '

Previously normal projects, these two days began to report an error, just started to quote 8080 port is occupied, and then changed the port, and then reported XML validation Disabel, changed the xmlvalidation=ture in the Server.xml. Finally reported cannot find the declaration of element ' Web-app '.

Today I asked my colleague, and my colleague said that it was because we upgraded our database server to cause the project to be useless. When defining a Session-factroy,

<property name= ' hibernatepropeties ' >

<prop key= "Hibernte.hbm2ddl.auto" >update</prop>

</property>

Change the above update to none, but have to xmlvalidation=false the first modification. So the project can start normally.