Which element of a web application deployment descriptor  element is required（）？

单项选择题Whichsecuritymechanismisemployedonlyontheserver-sidetolimitaccesstoresourcesorcomponents？（）

A. authorization
B. data integrity
C. confidentiality
D. authentication

单项选择题Whenusingaform-basedauthentication，whichactionmustbeusedintheloginform？（）

A. j_login
B. j_get_user
C. j_login_check
D. j_get_security
E. j_security_check

多项选择题Whichtwopiecesofinformationareneededwhendeclaringthewebresourcecollectioninthedeploymentdescriptor？（）

A. the URL pattern that requires authorization
B. the HTTP methods that require authorization
C. the users allowed access to the web resource
D. the J2EE roles allowed access to the web resource
E. the authentication mechanism required by the web resource

多项选择题Whichtwosecuritymechanismsprotecttheresponsestream？（）

A. authorization
B. data integrity
C. confidentiality
D. authentication

单项选择题Inform-basedauthentication，whatmustbeincludedintheHTMLreturnedfromtheURLspecifiedbytheelement？（）

A. a base-64 encoded user name and password
B. a form that POSTs to the j_security_check URL
C. an applet that requests the user name and password from the user
D. a hidden field that supplies the login-constraint used by the application