80db02c73af7001d17c382fc5cbc284e

java做的客房查询系统、 仅供初学者参考！

package Dao;

import java.util.*;
import java.sql.*;
import DBUtil.DBAccess;
/**
 * 数据库查询类
 * @author Administrator
 *
 */
public class BallotDao {
	/**
	 * 按照国家查询票数
	 * @param country
	 * @return
	 */
	public ArrayList queryTicket(String country) {
		ArrayList al=new ArrayList();
		String sql="select ticket from ballot where country=?";
		DBAccess db=new DBAccess();
		Connection con=db.getConnection();
		try {
			java.sql.PreparedStatement ps=con.prepareStatement(sql);
			ps.setString(1, country);
			java.sql.ResultSet rs=ps.executeQuery();
			while(rs.next()) {
				al.add(rs.getInt("ticket"));
			}
			rs.close();
			ps.close();
			con.close();
		}
		catch(java.sql.SQLException se) {
			se.printStackTrace();
		}
		return al;
		
	}
	/**
	 * 按照国家修改票数
	 * @param country
	 * @return
	 */
	public boolean updateTicket(String country) {
		DBAccess db=new DBAccess();
		Connection con=db.getConnection();
		String sql="update ballot set ticket=ticket+1 where country=?";
		try {
			java.sql.PreparedStatement ps=con.prepareStatement(sql);
			ps.setString(1, country);
			int count=ps.executeUpdate();
			if(count>0) {
				return true;
			}
			ps.close();
			con.close();
		}
		catch(java.sql.SQLException se) {
			se.printStackTrace();
		}
		return false;
	}

}