試題詳解

42 You have built a web application that you license to small businesses. The webapp uses a context parameter, called licenseExtension, which enables certain advanced features based on your client's license package. When a client pays for a specific service, you provide them with a license extension key that they insert into the ＜context-param＞ of the deployment descriptor. Not every client will have this context parameter so you need to create a context listener to set up a default value in the licenseExtension parameter. Which code snippet will accomplish this goal?
(A) You cannot do this because context parameters CANNOT be altered programmatically.
(B) String ext = context.getParameter('licenseExtension');if ( ext == null ) { context.setParameter('licenseExtension' DEFAULT);}
(C) String ext = context.getAttribute('licenseExtension');if ( ext == null ) { context.setAttribute('licenseExtension' DEFAULT);}
(D) String ext = context.getInitParameter('licenseExtension')if ( ext == null ) { context.resetInitParameter('licenseExtension' DEFAULT);}
(E) String ext = context.getInitParameter('licenseExtension')if ( ext == null ) { context.setInitParameter('licenseExtension' DEFAULT);}