using system;
using system.web;
using system.web.caching;E^站^网^络

namespace nguestbook.utility
{
    /**//// <summary>
    /// 辅助类，用于缓存操作
    /// </summary>
    public sealed class cacheaccess
    {
        /**//// <summary>
        /// 将对象加入到缓存中
        /// </summary>
        /// <param name="cachekey">缓存键</param>
        /// <param name="cacheobject">缓存对象</param>
        /// <param name="dependency">缓存依赖项</param>
        public static void savetocache(string cachekey, object cacheobject, cachedependency dependency)
        {
            cache cache = httpruntime.cache;
            cache.insert(cachekey, cacheobject, dependency);
        }E站&网络

        /**//// <summary>
        /// 从缓存中取得对象，不存在则返回null
        /// </summary>
        /// <param name="cachekey">缓存键</param>
        /// <returns>获取的缓存对象</returns>
        public static object getfromcache(string cachekey)
        {
            cache cache = httpruntime.cache;[E站@网络]

            return cache[cachekey];
        }
    }
}www~eZhannet~com

using system;
using system.configuration;
using system.reflection;
using system.web;
using system.web.caching;
using nguestbook.utility;

namespace nguestbook.factory
{
    /**//// <summary>
    /// 依赖注入提供者
    /// 使用反射机制实现
    /// </summary>
    public sealed class dependencyinjector
    {
        /**//// <summary>
        /// 取得数据访问层对象
        /// 首先检查缓存中是否存在，如果不存在，则利用反射机制返回对象
        /// </summary>
        /// <param name="classname">数据访问类名称</param>
        /// <returns>数据访问层对象</returns>
        public static object getdalobject(string classname)
        {
            /**//// <summary>
            /// 取得数据访问层名称，首先检查缓存，不存在则到配置文件中读取
            /// 缓存依赖项为web.config文件
            /// </summary>
            object dal = cacheaccess.getfromcache("dal");
            if (dal == null)
            {
                cachedependency filedependency = new cachedependency(httpcontext.current.server.mappath("web.config"));
                dal = configurationmanager.appsettings["dal"];
                cacheaccess.savetocache("dal", dal, filedependency);
            }

            /**//// <summary>
            /// 取得数据访问层对象
            /// </summary>
            string dalname = (string)dal;
            string fullclassname = dalname + "." + classname;
            object dalobject = cacheaccess.getfromcache(classname);
            if (dalobject == null)
            {
                cachedependency filedependency = new cachedependency(httpcontext.current.server.mappath("web.config"));
                dalobject = assembly.load(dalname).createinstance(fullclassname);
                cacheaccess.savetocache(classname, dalobject, filedependency);
            }E站&网络

            return dalobject;
        }

        /**//// <summary>
        /// 取得业务逻辑层对象
        /// 首先检查缓存中是否存在，如果不存在，则利用反射机制返回对象
        /// </summary>
        /// <param name="classname">业务逻辑类名称</param>
        /// <returns>业务逻辑层对象</returns>
        public static object getbllobject(string classname)
        {
            /**//// <summary>
            /// 取得业务逻辑层名称，首先检查缓存，不存在则到配置文件中读取
            /// 缓存依赖项为web.config文件
            /// </summary>
            object bll = cacheaccess.getfromcache("bll");
            if (bll == null)
            {
                cachedependency filedependency = new cachedependency(httpcontext.current.server.mappath("web.config"));
                bll = configurationmanager.appsettings["bll"];
                cacheaccess.savetocache("bll", bll, filedependency);
            }E站*网络

            /**//// <summary>
            /// 取得业务逻辑层对象
            /// </summary>
            string bllname = (string)bll;
            string fullclassname = bllname + "." + classname;
            object bllobject = cacheaccess.getfromcache(classname);
            if (bllobject == null)
            {
                cachedependency filedependency = new cachedependency(httpcontext.current.server.mappath("web.config"));
                bllobject = assembly.load(bllname).createinstance(fullclassname);
                cacheaccess.savetocache(classname, bllobject, filedependency);
            }[E站@网络]

            return bllobject;
        }
    }
}E站*网络

using system;
using nguestbook.idal;

namespace nguestbook.factory
{
    /**//// <summary>
    /// 数据访问层工厂，用于获取相应的数据访问层对象
    /// 使用abstract factory设计模式+facace设计模式+反射机制+缓存机制设计
    /// </summary>
    public sealed class dalfactory
    {
        /**//// <summary>
        /// 获取管理员数据访问层对象
        /// </summary>
        /// <returns>管理员数据访问层对象</returns>
        public static iadmindal createadmindal()      
 {
            return (iadmindal)dependencyinjector.getdalobject("admindal");
      }
        /**//// <summary>
        /// 获取留言数据访问层对象
        /// </summary>
        /// <returns>留言数据访问层对象</returns>
        public static imessagedal createmessagedal()
        {
            return (imessagedal)dependencyinjector.getdalobject("messagedal");
        }过~简单~的~网络~生活

        /**//// <summary>
        /// 获取评论数据访问层对象
        /// </summary>
        /// <returns>评论数据访问层对象</returns>
        public static icommentdal createcommentdal()
        {
            return (icommentdal)dependencyinjector.getdalobject("commentdal");
        }
    }
}www.eZhannet.com