javaweb学习（7）--Application/servletContext

这个是针对一整个webapp，所有窗口都共享的。

代码如下

public class ApplicationServlet extends HttpServlet{    @Override    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {        resp.setContentType("text/html");        PrintWriter writer = resp.getWriter();        //拿到的是整个上下文        ServletContext servletContext = this.getServletContext();        Integer accessCount = (Integer) servletContext.getAttribute("accessCount");        if(accessCount==null){            accessCount=new Integer(0);        }else{            accessCount=new Integer(accessCount.intValue()+1);        }        servletContext.setAttribute("accessCount", accessCount);        writer.println("<h3>accessCount:"+accessCount+"</h3>");    }}