boardservlet.java

java开发中的 数据分页

package com.jgxy.servlet;

import java.io.IOException;
import java.util.List;

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

import com.jgxy.bean.Msgboard;
import com.jgxy.dao.MsgboardDAO;

public class BoardServlet extends HttpServlet {

	private static final long serialVersionUID = 5898571538320691616L;

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//统一字符集
		request.setCharacterEncoding("utf-8");
		response.setCharacterEncoding("utf-8");
		
		//取得方法参数
		String method=request.getParameter("method");
		System.out.println("结果:"+method);
		if(method!=null && method.equals("save")){
			this.save(request, response);
		}
		//默认当前页是第一页
		int currentpage=1;
		//接收从客户端传过来的页数
		try{
			currentpage=Integer.parseInt(request.getParameter("page"));
		}catch(Exception e){
			//不做处理，如果出现异常 默认currentpage=1
		}
		
		MsgboardDAO msgboarddao=new MsgboardDAO();
		
		//总记录数
		int totalrecord=msgboarddao.getCount();
		//每页显示的记录数
		int maxresult=3;
		//总页数
		int totalpage=(totalrecord%maxresult==0?totalrecord/maxresult:totalrecord/maxresult+1);
		
		
		//如果客户输入的页面小于第一页，则currentpage=1
		if(currentpage<1){
			currentpage=1;
		}
		//如果客户输入的页面超过了最大页，则currentpage=totalpage
		if(currentpage>totalpage){
			currentpage=totalpage;
		}

		
		//每页开始的记录
		int firstindex=(currentpage-1)*maxresult;
		//每页的数据
		List<Msgboard> list=msgboarddao.getScrollData(firstindex,maxresult);
		
		

		//将分页数据存入request
		request.setAttribute("list", list);
		//将总记录数存入request
		request.setAttribute("totalrecord", totalrecord);
		//将总页数存入request
		request.setAttribute("totalpage", totalpage);
		//将当前页存入request
		request.setAttribute("currentpage", currentpage);
		//跳转页面
		RequestDispatcher dispatcher=request.getRequestDispatcher("/index.jsp");
		dispatcher.forward(request, response);
		
	}
	
	public void save(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException{
		String subject=request.getParameter("subject");
		String questioner=request.getParameter("questioner");
		String question=request.getParameter("question");
		
		if(questioner==null){
			questioner="匿名用户";
		}
		Msgboard m=new Msgboard();
		m.setSubject(subject);
		m.setQuestioner(questioner);
		m.setQuestion(question);
		MsgboardDAO mdao=new MsgboardDAO();
		mdao.save(m);
	}


	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request,response);
	}
		

}