Servlet中获取application对象的两种方法

在Servlet中，取得application有两种方法：

1.通过无参初始化方法，直接取得

public class Application extends HttpServlet {   
       
    public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException,ServletException {   
        this.doPost(request,response);   
    }   
       
    public void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException,ServletException {   
        //取得Application对象   
        ServletContext application=this.getServletContext();   
        //设置Application属性   
        application.setAttribute("name", "Magci");   
        //跳转到接收页面   
        response.sendRedirect("application.jsp");   
    }   
}  

2.通过有参初始化方法，必须使用config对象取得

public class Config extends HttpServlet {   
       
    private ServletConfig conf=null;   
       
    public void init(ServletConfig conf) throws ServletException {   
        //实例化config对象   
        this.conf=conf;   
    }   
       
    public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException,ServletException {   
        this.doPost(request,response);   
    }   
       
    public void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException,ServletException {   
        //通过config对象取得Application对象   
        ServletContext application=this.conf.getServletContext();   
        //设置Application属性   
        application.setAttribute("name", "Magci");   
        //跳转到接收页面   
        response.sendRedirect("config.jsp");   
    }   
}