在applicationJSP中的对象被称为ServletContext在servlet对象。可以通过继承的GenericServlet#getServletContext()方法使用。您可以在servlet的任何地方（init(ServletConfig)方法除外）调用此函数。

public class YourServlet extends HttpServlet {

    @Override
    public void init() throws ServletException { 
         ServletContext ctx = getServletContext(); 
         // ...
    }

    @Override
    public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { 
         ServletContext ctx = getServletContext(); 
         // ...
    }

    @Override
    public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { 
         ServletContext ctx = getServletContext(); 
         // ...
    }

}