錯誤:The content of element type "web-app" must match "(icon?,display-
name?,description?,distributable?,context-param*,filter*,filter-mapping*,listener*,servlet*,servlet-
mapping*,session-config?,mime-mapping*,welcome-file-list?,error-page*,taglib*,resource-env-
ref*,resource-ref*,security-constraint*,login-config?,security-role*,env-entry*,ejb-ref*,ejb-local-ref*)".
- No grammar constraints (DTD or XML schema) detected for the document.
注意順序:<servlet>,<servlet-mapping>需要分開寫,先寫所有的servlet,後寫servlet-mapping