userdao.java

这是本人最初练习ajax时的小程序,是用ＪＳＰ写的

package com.chinasoft.servlet;

import java.sql.*;

import org.apache.commons.dbcp.BasicDataSource;

public class UserDAO {
       private String QUERY_STRING="select * from usertable where username=? and password=?";
       private Connection conn=null;
       protected void getConn(){
        try {
        	BasicDataSource ds=Datasourcefactory.getDataSource();
			this.conn=ds.getConnection();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
       }
       protected void freeConn(){
    	   try {
			this.conn.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
       }
       public boolean Login(String username,String psw ){
    	   getConn();
    	   boolean flag=false;
    	   try {
			PreparedStatement smtp=conn.prepareStatement(QUERY_STRING);
			smtp.setString(1,username);
			smtp.setString(2,psw);
			ResultSet rs=smtp.executeQuery();
			if(rs.next()){
				flag=true;
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally{
			freeConn();
		}
    	   return flag;
    	   
       }
       
}