daoset.java

java三层架构（MVC)实现的在线图书销售系统。其中应用到工厂

package accp.yyw.model.dao;

/**
 * <p>Title: BookShop</p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2005</p>
 * <p>Company: accp</p>
 * @author yyw
 * @version 1.0
 */

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

import accp.yyw.model.tool.*;
import accp.yyw.model.bean.*;

public class DAOSet {

        private HashMap daos;

        private static DAOSet instance;

    private Connection connection;

    private String driver = null;
    private String username= null;
    private String password = null;
    private String url = null;

    private DAOSet(){

              java.util.Properties properties = null;

              try{

                properties = PropertiesManager.getProperties("accp.yyw.model.tool.jdbc_config");

                driver = properties.getProperty("jdbc.driver");
                url = properties.getProperty("jdbc.url");
                username = properties.getProperty("jdbc.username");
                password = properties.getProperty("jdbc.password");

                Class.forName(driver);
                connection = DriverManager.getConnection(url,username,password);
              }
              catch(ClassNotFoundException cnfe) {

                         System.out.println("ClassNotFoundException :");
                         System.out.println(cnfe);
                 }
                 catch(SQLException sqle) {

                         System.out.println("Connection Exception :");
                         System.out.println(sqle);
                 }
                 catch(Exception e) {

                         System.out.println("Connection unknown Exception :");
                         System.out.println(e);
                 }

                 this.initDAOs();
    }

    public static DAOSet getInstance(){

              if (instance == null){

                      instance = new DAOSet();
                      System.out.println("Connection is succes!");
              }

              return instance;
    }

  /*  private MemberVo makeMember(ResultSet rs){

        try{

                  MemberVo memberbean = new MemberVo();
                  rs=
                  if(rs.next()){

                    memberbean.setMembername(rs.getString("memberName").trim());
                    return memberbean;
                  }
        }
        catch (Exception e){

                  System.out.println(e);
        }

        return null;
          }*/

          private void initDAOs() {

            daos = new HashMap();

            daos.put("memberdao",new MemberDAO(connection));
        }

         public Idao getDAO(String daoname) throws DAOException {

                if(daos.containsKey(daoname.toLowerCase())) {

                          return (Idao)daos.get(daoname.toLowerCase());
                  }
                  else{

                          throw new DAOException("Invalid DAO Identifier ! in DAOSet");
                  }
        }
}