HttpServlet 是一个扩展了 GenericServlet 的抽象类.
http://download.oracle.com/otn-pub/jcp/sjp-1_1-pr2-spec-oth-JSpec/sjp-1_1-pr2-spec.pdf?AuthParam=1420784256_cb4cc389a12bca819410a75f74b1dec0
HttpServlet 是一个扩展了 GenericServlet 的抽象类.
http://download.oracle.com/otn-pub/jcp/sjp-1_1-pr2-spec-oth-JSpec/sjp-1_1-pr2-spec.pdf?AuthParam=1420784256_cb4cc389a12bca819410a75f74b1dec0