学习进度10

①按时间段查询显示省市的疫情状况

②实现图表的展示全国的患者人数

第一个功能比较好实现：从前台中获取这两个时间数据，在后台进行数据的查询，格式的转换，找到数据库中在这两个区间的数据，然后将他们展示出来

package servlet;

import java.io.IOException;
import java.util.ArrayList;

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

import Dao.predao;
import Bean.Pre;

/**
* Servlet implementation class checkfind
*/
@WebServlet("/checkfind")
public class checkfind extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#HttpServlet()
*/
public checkfind() {
super();
// TODO Auto-generated constructor stub
}

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
request.setCharacterEncoding("utf-8");
String btime=request.getParameter("btime");
String etime=request.getParameter("etime");
predao dao=new predao();
ArrayList<Pre> list=null;
list=dao.findtime(btime,etime);
if(list!=null)
{
request.setAttribute("pres", list);
request.getRequestDispatcher("listall.jsp").forward(request, response);
}
else
{
request.setAttribute("message", "没有符合的信息");
request.getRequestDispatcher("listall.jsp").forward(request, response);
}
}

/**
* @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);
}

}