package cn.bdqn.entity;
import java.util.List;

public class Page {
	//总记录数        从数据库查询
	private int totalRecords;
	
	//页面大小,即每页显示多少条
	private int pageSize=5;
	
	//总页数      计算出来(总记录数/页面大小)向上取整
	private int totalPage;
	
	//当前页码      从页面上传进来
	private int currPage;
	
	//每页开始查询的索引       计算出来  (当前页码-1)*页码容量
	private int startIndex;
	
	//每页新闻集合
	private List customerList;

	public Page(int currPage,int totalRecords){
		this.totalRecords=totalRecords;
		this.totalPage=totalRecords/pageSize==0?totalRecords/pageSize:totalRecords/pageSize+1;
		this.currPage=currPage;
		this.startIndex=(currPage-1)*pageSize;
	}
	
//然后set/get方法

           //分页显示所有的客户
	public List<Customer> allCustomer(int startIndex,int pageSize);
	   //分页查询总记录数
	int findPageCustomer();

/**
	 * 分页显示客户列表
	 */
	@Override
	public List<Customer> allCustomer(int startIndex, int pageSize) {
		String sql="select * from customer limit ? ,? ";
		List<Customer> list =null;
		try {
			list=qr.query(sql, new BeanListHandler<Customer>(Customer.class), startIndex,pageSize);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return list;
	}

	/**
	 * 查询记录总数          查询有多少信息
	 */
	@Override
	public int findPageCustomer() {
		String sql="select count(1) from customer";
		int count=0;
		try {
		long lr=(Long) qr.query(sql, new ScalarHandler(1));
		count=Integer.parseInt(lr+"");
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return count;
	}
	

//通过传过来现在的页面获取Page里的所有信息
public  Page findPage(int currentPage);

/**
	 * 通过传过来的currentPage来确定Page的信息
	 */
	@Override
	public Page findPage(int currPage) {
		int totalRecords=cd.findPageCustomer();  //总记录数
		Page page = new Page(currPage,totalRecords); 
		List<Customer> list=cd.allCustomer(page.getStartIndex(), page.getPageSize());
		page.setCustomerList(list);
		return page;
	}

public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//String path = request.getContextPath();
		String currentPageStr = request.getParameter("pagenum");
		int currentPage=1;
		if(currentPageStr!=null){
			currentPage=Integer.parseInt(currentPageStr);
		}
		CustomerService cs=new CustomerServiceImpl() ;
			Page page=cs.findPage(currentPage);
			request.setAttribute("page", page);
			request.getRequestDispatcher("../WEB-INF/jsp/index.jsp").forward(request, response);
	}

总记录数:${requestScope.page.totalRecords }  当前第${page.currPage }页/共${page.totalPage }页   
        <a href=http://www.mamicode.com/"${path }/servlet/start_index?pagenum=1">首页</a> &nbsp; 
        <a href=http://www.mamicode.com/"${path }/servlet/start_index?pagenum=${page.currPage-1<1?1:page.currPage-1}">上一页</a> &nbsp; 
        <a href=http://www.mamicode.com/"${path }/servlet/start_index?pagenum=${page.currPage+1<page.totalPage?page.currPage+1:page.totalPage}">下一页</a> &nbsp; 
        <a href=http://www.mamicode.com/"${path }/servlet/start_index?pagenum=${page.totalPage}">尾页</a>
        <input id="bottom" type="button" value=http://www.mamicode.com/"跳转至"/><input type="text" style="width:33PX" id="num" value=http://www.mamicode.com/"2"/>