pagedate.java

dwr分页就是 ajax的一个框架拉 可以通过javascript在前台调用后台的java代码

package com.jw.dao;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import com.jw.db.*;
import com.jw.po.User;

public class Pagedate {
	private Connection con;

	private Statement st;

	private ResultSet re;

	// 得到表中的所有数据
	public int selectcount() {
		String sql = "select count(*) from users";
		con = Dbmanage.getcon();
		try {
			st = con.createStatement();
			re = st.executeQuery(sql);
			if (re.next()) {
				System.out.println("re.getInt(1)--------->"+re.getInt(1));
				return re.getInt(1);
			} else {
				return 0;
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return 0;
		}finally
		{
			try {
				re.close();
				st.close();
				con.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}

	// 得到页数
	public int getmaxpage() {
		int usersdate = selectcount();
		int mypage = 0;
		if (usersdate != 0 && usersdate % 5 == 0) {
			mypage = usersdate / 5;
			System.out.println("usersdate / 5----------------->>"+usersdate / 5);
		}
		if (usersdate != 0 && usersdate % 5 != 0) {
			mypage = (int) Math.abs((double) usersdate / 5)+1;
			System.out.println("mypage--------------->>"+mypage);
		}
		System.out.println("zui da "+mypage);
		return mypage;
	}

	// 得到当前页数的记录
	public List pagelist(int currentpage) {
		System.out.println("-----------"+currentpage);
		List l = new ArrayList();
		int listpage = (currentpage - 1)*5;
		String sql = "select  top 5 *  from users where userID not in (select top "
				+ listpage
				+ " userID from users order by userID asc )  order by userID asc";
		con = Dbmanage.getcon();
		try {
			st = con.createStatement();
			re = st.executeQuery(sql);
			while (re.next()) {
				User u = new User();
				u.setUserID(re.getInt(1));
				u.setUserName(re.getString(2));
				u.setUserPwd(re.getString(3));
				l.add(u);
			}
			return l;
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}finally
		{
			try {
				re.close();
				st.close();
				con.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
}