乐在其中设计模式(C#) - 工厂方法模式(Factory Method Pattern)
作者: 介绍 定义一个用于创建对象的接口,让子类决定将哪一个类实例化。Factory Method使一个类的实例化延迟到其子类。 示例 有SqlMessage和XmlMessage,用Factory Method来实例化它们。 MessageModel using System; using System.Collections.Generic; using System.Text; namespace Pattern.FactoryMethod { /**//// <summary> /// Message实体类 /// </summary> public class MessageModel { /**//// <summary> /// 构造函数 /// </summary> /// <param name="msg">Message内容</param> /// <param name="pt">Message发布时间</param> public MessageModel(string msg, DateTime pt) { this._message = msg; this._publishTime = pt; } private string _message; /**//// <summary> /// Message内容 /// </summary> public string Message { get { return _message; } set { _message = value; } } private DateTime _publishTime; /**//// <summary> /// Message发布时间 /// </summary> public DateTime PublishTime { get { return _publishTime; } set { _publishTime = value; } } }}
AbstractMessage using System; using System.Collections.Generic; using System.Text; namespace Pattern.FactoryMethod { /**//// <summary> /// 操作Message抽象类(Product) /// </summary> public abstract class AbstractMessage { /**//// <summary> /// 获取Message /// </summary> /// <returns></returns> public abstract List<MessageModel> Get(); /**//// <summary> /// 插入Message /// </summary> /// <param name="mm">Message实体对象</param> /// <returns></returns> public abstract bool Insert(MessageModel mm); }}
SqlMessage using System; using System.Collections.Generic; using System.Text; namespace Pattern.FactoryMethod { /**//// <summary> /// Sql方式操作Message(ConcreteProduct) /// </summary> public class SqlMessage : AbstractMessage { /**//// <summary> /// 获取Message /// </summary> /// <returns></returns> public override List<MessageModel> Get() { List<MessageModel> l = new List<MessageModel>(); l.Add(new MessageModel("SQL方式获取Message", DateTime.Now)); return l; } /**//// <summary> /// 插入Message /// </summary> /// <param name="mm">Message实体对象</param> /// <returns></returns> public override bool Insert(MessageModel mm) { // 代码略 return true; } }}
XmlMessage using System; using System.Collections.Generic; using System.Text; namespace Pattern.FactoryMethod { /**/ /// <summary> /// Xml方式操作Message(ConcreteProduct) /// </summary> public class XmlMessage : AbstractMessage { /**/ /// <summary> /// 获取Message /// </summary> /// <returns></returns> public override List < MessageModel > Get() { List < MessageModel > l = new List < MessageModel > (); l.Add( new MessageModel( " XML方式获取Message " , DateTime.Now)); return l; } /**/ /// <summary> /// 插入Message /// </summary> /// <param name="mm"> Message实体对象 </param> /// <returns></returns> public override bool Insert(MessageModel mm) { // 代码略 return true ; } } }
AbstractMessageFactory using System; using System.Collections.Generic; using System.Text; namespace Pattern.FactoryMethod { /**//// <summary> /// 抽象Message工厂(Creator) /// </summary> public abstract class AbstractMessageFactory { // An Operation /**//// <summary> /// 工厂方法 /// </summary> /// <returns>AbstractMessage</returns> public abstract AbstractMessage CreateMessage(); }}
SqlMessageFactory using System; using System.Collections.Generic; using System.Text; namespace Pattern.FactoryMethod { /**//// <summary> /// SqlMessage工厂(ConcreteCreator) /// </summary> public class SqlMessageFactory : AbstractMessageFactory { /**//// <summary> /// 实现工厂方法,返回SqlMessage对象 /// </summary> /// <returns></returns> public override AbstractMessage CreateMessage() { return new SqlMessage(); } }}
XmlMessageFactory using System; using System.Collections.Generic; using System.Text; namespace Pattern.FactoryMethod { /**/ /// <summary> /// XmlMessage工厂(ConcreteCreator) /// </summary> public class XmlMessageFactory : AbstractMessageFactory { /**/ /// <summary> /// 实现工厂方法,返回XmlMessage对象 /// </summary> /// <returns></returns> public override AbstractMessage CreateMessage() { return new XmlMessage(); } } }
client using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using Pattern.FactoryMethod; public partial class FactoryMethod : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { AbstractMessageFactory amf = new SqlMessageFactory(); AbstractMessage am = amf.CreateMessage(); Response.Write(am.Insert(new MessageModel("插入", DateTime.Now))); Response.Write("<br />"); Response.Write(am.Get()[0].Message + " " + am.Get()[0].PublishTime.ToString()); Response.Write("<br />"); amf = new XmlMessageFactory(); am = amf.CreateMessage(); Response.Write(am.Insert(new MessageModel("插入", DateTime.Now))); Response.Write("<br />"); Response.Write(am.Get()[0].Message + " " + am.Get()[0].PublishTime.ToString()); }}
运行结果 True SQL方式获取Message 2007-5-4 22:34:39 True XML方式获取Message 2007-5-4 22:34:39 参考 OK