servlet---response方法

统计一个servlet的访问次数
需求:
有一个servlet(countServlet),每访问一次这个servlet,将访问的次数+1,
当我们访问另一个servlet(showServlet),展示访问CountServlet的次数


需要创建2个sevlet(countServlet--计数  showServlet--获取显示)




package cn.itcast.web;


import java.io.IOException;


import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class CountServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//获取servletContext对象
ServletContext con = getServletContext();
//里面是否有数据
Integer count = (Integer) con.getAttribute("count");
//判断
if(count == null){
count = 1;
}else{
count = count + 1;
}
//存到ServletContext中
con.setAttribute("count", count);
}



protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}


}






package cn.itcast.web;


import java.io.IOException;


import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class ShowServlet extends HttpServlet {
private static final long serialVersionUID = 1L;


//获取访问量
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

//设置编码，防止中文乱码
response.setContentType("text/html;charset=utf-8");
//获取全局变量---servletcontext
ServletContext scon = getServletContext();
//取访问量
Object count = scon.getAttribute("count");
//判断
if(count==null){
response.getWriter().print("没有访问量");
}else{
response.getWriter().print("一共有"+count+"个访问量");
}
}



protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}


}




在web.xml上输入
<servlet>
    <description></description>
    <display-name>CountServlet</display-name>
    <servlet-name>CountServlet</servlet-name>
    <servlet-class>cn.itcast.web.CountServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>CountServlet</servlet-name>
    <url-pattern>/count</url-pattern>
  </servlet-mapping>
  <servlet>
    <description></description>
    <display-name>ShowServlet</display-name>
    <servlet-name>ShowServlet</servlet-name>
    <servlet-class>cn.itcast.web.ShowServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>ShowServlet</servlet-name>
    <url-pattern>/show</url-pattern>
  </servlet-mapping>