javaWeb 設置應用域屬性

package com.my.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class ContextServlet
 */
@WebServlet("/ContextServlet")
public class ContextServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ContextServlet() {
        super();
    }
    
	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("text/html;charset=UTF-8");
		ServletContext context = super.getServletContext();
		Integer count = (Integer)context.getAttribute("count");
		if(count==null) {
			count=1;
		}else {
			count++;
		}
		context.setAttribute("count", count);
		PrintWriter out = response.getWriter();
		out.println("<p>本網訪問的人數是："+count+"</p>");
		out.flush();
		out.close();
	}
	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}