(When developing JSF with Myeclipse, it is necessary to import these jar packages, otherwise an exception will occur.
jsfjar\commons-beanutils.jar
jsfjar\commons-collections.jar
jsfjar\commons-digester.jar
jsfjar\commons-logging.jar
jsfjar\jsf-api.jar
jsfjar\jsf-impl.jar
jsfjar\jstl.jar
jsfjar\standard.jar
.....too many files .....)