userinfobean.java

简单的分页类

package com.accp;

import java.sql.*;
import java.util.*;

public class UserInfoBean {
    public UserInfoBean() {
    }

    public int getPageCount(int pageSize) { // 得到数据库中的总记录数并计算得到页数
        int returnCount = 0;
        int allCount = 0;
        String sql = "select count(*) as count from context";
        BaseDao db = new BaseDao();
        try {
            ResultSet rs = db.executeQuery(sql);
            if (rs.next()) {
                allCount = rs.getInt("count");
            }
        } catch (Exception ex) {}
        returnCount = (allCount + pageSize - 1) / pageSize;
        return returnCount;
    }


    public ArrayList<ContextForm> getInfos(int pageSize, int pageNow) { //每一次从数据库中取出只定的数量
        BaseDao db = new BaseDao();
        ArrayList<ContextForm> arr = new ArrayList<ContextForm>();
        String sql = "select * from context";
        try {
            ResultSet rs = db.executeQuery(sql);

            rs.absolute((pageNow - 1) * pageSize + 1); //油标定位于哪一行
            for (int i = 0; i < pageSize; i++) {
                ContextForm contextForm = new ContextForm();
                contextForm.setID(rs.getString("ID"));
                contextForm.setUserName(rs.getString("userName"));
                contextForm.setMarktime(rs.getString("marktime"));
                contextForm.setTitle(rs.getString("title"));
                contextForm.setContext(rs.getString("context"));
                arr.add(contextForm);
                if (!rs.next()) {
                    break;
                }
            }
        } catch (Exception ex) {
        } finally {
            db.close();
        }
        return arr;
    }

    public boolean isValidate(UserInfo userinfo) { //登陆是否有效
        BaseDao db = new BaseDao();
        String sql = "select * from userinfo where userName='" +
                     userinfo.getUserName() + "' and passWord='" +
                     userinfo.getPassWord() + "'";
        try {
            ResultSet rs = db.executeQuery(sql);
            if (rs.next()) {
                return true;
            }
        } catch (Exception ex) {
        } finally {
            db.close();
        }
        return false;
    }

    public void insertInfos(ContextForm contextForm) throws SQLException { //向数据库中插入数据
        BaseDao db = new BaseDao();
        String sql =
                "insert into context(userName,title,context,marktime) values ('" +
                contextForm.getUserName() + "','" + contextForm.getTitle() +
                "','" + contextForm.getContext() + "','" + Tools.getCurrentTime() +
                "') ";
        sql = Tools.getChn(sql); //Tools来转码

        try {
            db.executeUpdate(sql);
        } catch (SQLException ex) {
            throw new SQLException(ex.toString());
        } finally {
            db.close();
        }
    }

    public void deleteInfos(String ID) { //删除数据
        BaseDao db = new BaseDao();
        if (ID == null) {
            return;
        }
        String sql = "delete from context where id=" + ID;
        try {
            db.executeUpdate(sql);
        } catch (Exception ex) {
            System.out.println(ex);
        } finally {
            db.close();
        }
    }
}