单项选择题
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
多项选择题 AJSPpageneedstoinstantiateaJavaBeantobeusedbyonlythatpage.Whichtwojsp：useBeanattributesmustbeusedtoaccessthisattributeintheJSPpage？（）
单项选择题 ForagivenServletResponseresponse，whichretrievesanobjectforwritingbinarydata？（）
单项选择题 Which theHTTPmethodrepresentsarequestforinformationaboutthesupportedmethodsonanHTTPserver？（）