duser.java

在线模拟选课系统

/*
 * This product includes software developed by the
 * Apache Software Foundation (http://www.apache.org/).
 */
package ch07.database;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.*;

import javax.servlet.http.HttpSession;

import ch07.*;
import ch07.object.unit.*;

/**
 * 针对用户信息（登录）的数据处理类
 * @author ShenYK
 * @version 1.0
 */
public class DUser extends DCommon
{
    public User getUserInfo ( String username, 
    		                   String password )
        throws Exception
    {
        //获得数据库连接
        Connection conn = this.getDBConnection();
        if ( conn == null )
        {
            throw new Exception("数据库连接获得失败！");
        }
        Statement stmt = null;
        ResultSet rs = null;
        
        try
        {
            //检查数据库中是否已经有该用户了
            stmt = conn.createStatement();
            //执行SQL语句
            String sQuery = "select * from user "
                          + "where username='" + username + "' "
                          + "and password='" + password +"'";
            rs = stmt.executeQuery( sQuery );
            if ( rs.next() )
            {
                User oUser = new User(rs);
                
                return oUser;
            }
            else
            {
                return null;
            }
        }
        catch(Exception e)
        {
            e.printStackTrace();
            throw e;
        }
        finally
        {
            try
            {
                rs.close();
                stmt.close();
                conn.close();
            }catch(Exception ex)
            {
            }
        }
    }
}