思路：
1.新建一个Servlet类继承HttpServlet，重写doGet（）和doPost（）方法；
2.在doPost方法中调用doGet（）方法，在doGet()方法中实现统计网站被访问次数的功能，用户每请求一次servlet，使得访问次数times加1；
3.获取ServletContext，通过它的功能记住上一次访问后的次数。
实现代码：
package readPath;
import java.io.IOException;
import java.io.PrintWriter;
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 test001 extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=GB2312");
//设置编码，不然中文会变成乱码
ServletContext context = this.getServletContext();
PrintWriter out = response.getWriter();
Integer times =(Integer)context.getAttribute("times");
if(times==null) {
times = new Integer(1);
}else {
times = new Integer(times.intValue()+1);
}
out.println("<html><head><title>");
out.println("页面访问统计~");
out.println("</title></head><body>");
out.println("当前页面被访问过了");
out.println("<font color=red size=20>"+times+"</font>次");
//设置属性，将times保存到当前的上下文中
context.setAttribute("times", times);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doGet(req, resp);
}
}
运行结果：
