javax.servlet.jsp.PageContext;
就是上面这个这个包，找不到呢~~为什么？
还有这个javax.servlet.http.*;也找不到，这些东东jdk不带吗？我用的jbuilder，也装了BAS。

在project--->project properties里的required libraries里加上servlet

你需要在CLASSPATH中指明javax.servlet包。
你用什么服务器？我的tomcat是3.2.1版本

servlet.jar包含的类有：

javax/
javax/servlet/
javax/servlet/http/
javax/servlet/jsp/
javax/servlet/jsp/tagext/
javax/servlet/http/Cookie.class
javax/servlet/http/HttpServlet.class
javax/servlet/http/NoBodyResponse.class
javax/servlet/http/NoBodyOutputStream.class
javax/servlet/http/HttpServletRequest.class
javax/servlet/http/HttpServletResponse.class
javax/servlet/http/HttpSession.class
javax/servlet/http/HttpSessionBindingEvent.class
javax/servlet/http/HttpSessionBindingListener.class
javax/servlet/http/HttpSessionContext.class
javax/servlet/http/HttpUtils.class
javax/servlet/http/LocalStrings.properties
......
javax/servlet/jsp/PageContext.class
......

里面包含的有你需要的类和包。
注意你的类路径！