ado.net快速上手实践篇（二）

我们接着上文继续完成我们的 ado.net简单实践。

五、dal层数据访问实现
在这里我们使用前一篇文章里实现的数据持久化层和伪SqlMapper对象，实现数据操作。下面我们来看看Dal 下核心的Dao如何实现：
还记得我们在IBatis.net下面的dao类是怎么实现的吗？没错，我们根据一个基类BaseDAO和它的构造函数，实现dao的配置加载。但是楼猪的实现没有那么复杂和强大，本文的实现其实就是通过BaseDAO和构造函数获取数据库连接对象的key，初始化一个SqlMapper，然后利用SqlMapper对象进行基本的CRUD等等数据操作。那么我们如何利用BaseDAO和构造函数就像以前在IBatis.net系列文章里的提到的Dal层下那样进行 SqlMapper的初始化呢？
1、在AdoNetDataAccess.Mapper下我们定义公共的BaseDAO类

代码

namespace AdoNetDataAccess.Mapper
{
    public abstract class BaseDAO
    {
        #region Properties

        public SqlMapper SqlMapper { get; set; }

        #endregion

        #region Constructor

        private BaseDAO()
        {
        }

        /// <summary>
        /// SqlMapper属性适用
        /// </summary>
        /// <param name="mapperName"></param>
        public BaseDAO(string mapperName)
        {
            this.SqlMapper = MapperUtill.GetMapper(mapperName);
        }

        #endregion
    }
}

2、初始化SqlMapper的实用类

代码
using System;
using System.Collections.Generic;
using System.Configuration;

namespace AdoNetDataAccess.Mapper
{
    using AdoNetDataAccess.Core.Contract;
    using AdoNetDataAccess.Core.Implement;

    public sealed class MapperUtill
    {
        #region fields

        public static string currentSqlKey = "sqlConn";

        public static int cmdTimeOut = 15;

        private static readonly object objSync = new object();

        private static readonly IDictionary<string, SqlMapper> dictMappers = new Dictionary<string, SqlMapper>();

        #endregion

        #region constructor and methods

        private MapperUtill()
        {

        }

        static MapperUtill()
        {
            try
            {
                cmdTimeOut = int.Parse(ConfigurationManager.AppSettings["db_timeOut"]);
            }
            catch
            {
                cmdTimeOut = 15;
            }
            //实例化SqlDbMapper
            for (int i = 0; i < ConfigurationManager.ConnectionStrings.Count; i++)
            {
                string key = ConfigurationManager.ConnectionStrings[i].Name;
                string value = ConfigurationManager.ConnectionStrings[i].ConnectionString;
                CreateMapper(key, value, cmdTimeOut);
            }
        }

        public static SqlMapper GetSqlMapper(string key)
        {
            return MapperUtill.GetMapper(key);
        }

        public static SqlMapper GetCurrentSqlMapper()
        {
            return MapperUtill.GetMapper(currentSqlKey);
        }

        public static void CreateMapper(string connKey, string sqlConStr, int connTimeOut)
        {
            IDbOperation operation = new SqlServer(sqlConStr, connTimeOut);
            SqlMapper mapper = new SqlMapper(operation);
            dictMappers.Add(connKey.ToUpper().Trim(), mapper);//不区分大小写
        }

        public static SqlMapper GetMapper(string sqlConKey)
        {
            if (string.IsNullOrEmpty(sqlConKey))
            {
                throw new Exception("数据库连接字符串主键为空!");
            }
            sqlConKey = sqlConKey.ToUpper();//不区分大小写
            SqlMapper mapper = null;
            if (dictMappers.ContainsKey(sqlConKey))
            {
                mapper = dictMappers[sqlConKey];
            }
            else
            {
                throw new Exception(string.Format("没有{0}所对应的数据库连接", sqlConKey));
            }
            return mapper;
        }

        /// <summary>
        /// 释放所有
        /// </summary>
        public void Release()
        {
            foreach (KeyValuePair<string, SqlMapper> kv in dictMappers)
            {
                SqlMapper mapper = kv.Value;
                if (mapper == null)
                {
                    continue;
                }
                mapper.CurrentDbOperation.CloseConnection();
            }
            dictMappers.Clear();
        }

        #endregion

    }
}

这个实用类的重要作用就是初始化配置文件里connectionStrings配置节点，以获取sql连接对象必须的连接字符串。
3、 PersonDao类
下面就是针对具体的Person表的数据操作了：

代码
using System.Collections.Generic;
using System.Data;

namespace AdoNetDataAccess.Dal.Dao
{
    using AdoNetDataAccess.Dal.Model;
    using AdoNetDataAccess.Dal.Utility;
    using AdoNetDataAccess.Mapper;

    public class PersonDao : BaseDAO
    {
        public PersonDao()
            : base("sqlConn")//sqlConn是<connectionStrings>配置节点的一个name
        {
        }

        public int Insert(string sqlInsert)
        {
            int id = this.SqlMapper.Insert(sqlInsert);
            //object obj = this.SqlMapper.ExecuteScalar(sqlInsert, System.Data.CommandType.Text, null);
            return id;
        }

        public bool BatchInsert(IList<Person> listModels)
        {
            int batchSize = 50000;
            int copyTimeOut = 60;
            DataTable dt = DataTableHelper.CreateTable<Person>(listModels);
            bool flag = this.SqlMapper.BatchInsert(typeof(Person).Name, batchSize, copyTimeOut, dt);
            return flag;
        }

        public int Update(string sqlUpdate)
        {
            int result = this.SqlMapper.Update(sqlUpdate);
            return result;
        }

        public IList<Person> SelectPersons(string sqlSelect)
        {
            IList<Person> listPersons = this.SqlMapper.QueryForList<Person>(sqlSelect);
            return listPersons;
        }

        public IDictionary<int, Person> SelectDictPersons(string sqlSelect)
        {
            IDictionary<int, Person> dictPersons = this.SqlMapper.QueryForDictionary<int, Person>("Id", sqlSelect);
            return dictPersons;
        }

        public DataTable SelectPersonTable(string sqlSelect)
        {
            DataTable dt = this.SqlMapper.FillDataTable(sqlSelect, CommandType.Text, null);
            return dt;
        }

        public DataSet SelectPersonDataSet(string sqlSelect)
        {
            DataSet ds = this.SqlMapper.FillDataSet(sqlSelect, CommandType.Text, null);
            return ds;
        }

        public int Delete(string sqlDelete)
        {
            int result = this.SqlMapper.Delete(sqlDelete);
            return result;
        }

    }
}

到这里，一个dao类操作就实现了。然后我们按步就班实现对外调用的服务接口。在表现层调用吧。
六、表现层的调用
1、配置文件

代码
  <appSettings>
    <add key="db_timeOut" value="5000"/>
  </appSettings>
  <connectionStrings>
    <add name="sqlConn" connectionString="Data Source=.\sqlexpress; Initial Catalog=TestDb; User Id=sa; Password=123456;"/>
    <add name="sqlConnStr1" connectionString="Data Source=.\sqlexpress; Initial Catalog=TestDb; User Id=sa; Password=123456;"/>
    <add name="sqlConnStr2" connectionString="Data Source=.\sqlexpress; Initial Catalog=TestDb; User Id=sa; Password=123456;"/>
  </connectionStrings>
其中，connectionString是必须的，如果没有，我们无法加载调用可用的 SqlMapper。
2、CRUD操作测试

代码
using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;

namespace OOXXWebApp
{
    using AdoNetDataAccess.Dal;
    using AdoNetDataAccess.Dal.Model;

    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                //增删改查测试
                string sqlInsert = "INSERT Person (FirstName,LastName,Weight,Height) VALUES( 'jeff','wong',70,180) SELECT @@IDENTITY FROM Person(NOLOCK)";
                string sqlUpdate = "UPDATE Person SET Height=178 WHERE Id=1";
                string sqlSelect = "SELECT TOP 100 * FROM Person(NOLOCK)";
                string sqlDelete = "DELETE Person  WHERE Id>10 AND Id<100";

                IList<Person> listModels = new List<Person>();
                for (int i = 0; i < 500000; i++)
                {
                    Person model = new Person();
                    model.FirstName = "Jeff";
                    model.LastName = "Wong";
                    model.Weight = 70;
                    model.Height = 180;
                    listModels.Add(model);
                }

                Response.Write("Test Beginning......<br/>");

                int id = ServiceFactory.CreatePersonService().Add(sqlInsert);
                Response.Write(string.Format("<br/>Insert and return id:{0}", id));

                bool flag = ServiceFactory.CreatePersonService().BatchInsert(listModels);
                Response.Write(string.Format("<br/> Batch Insert {0}", flag ? "succeed" : "failed"));

                IList<Person> listPersons = ServiceFactory.CreatePersonService().GetPersons(sqlSelect);
                Response.Write(string.Format("<br/>Select pesons and return persons:{0}", listPersons.Count));

                IDictionary<int, Person> dictPersons = ServiceFactory.CreatePersonService().GetDictPersons(sqlSelect);
                Response.Write(string.Format("<br/>Select pesons and return dictionary persons:{0}", dictPersons.Count));

                DataTable dt = ServiceFactory.CreatePersonService().GetPersonTable(sqlSelect);
                Response.Write(string.Format("<br/>Select pesons and return persons:{0}", dt.Rows.Count));

                DataSet ds = ServiceFactory.CreatePersonService().GetPersonDataSet(sqlSelect);
                Response.Write(string.Format("<br/>Select pesons and return persons:{0}", ds.Tables[0].Rows.Count));

                int affectNum = ServiceFactory.CreatePersonService().Modify(sqlUpdate);
                Response.Write(string.Format("<br/>Update and affect rows :{0}", affectNum));

                affectNum = 0;
                affectNum = ServiceFactory.CreatePersonService().Remove(sqlDelete);
                Response.Write(string.Format("<br/>Delete and affect rows :{0}", affectNum));

                Response.Write("<br/><br/>Test End.");
            }
        }
    }
}

这个就不用多说了吧，表现层写SQL语句调用写好的服务就行了。比较不舒服的地方就是SQL语句不得不写在类里面，如果自动生成或者独立放在xml下实现可配置的形式那就更好了，当然sql语句不是我们讨论的重点，您有好的方法可以自己扩展实现更人性化的功能，减少书写SQLl语句的工作。

七、最后，对demo工程文件结构进行简单说明。
1、数据持久化层AdoNetDataAccess.Core
2、 SqlMapper层AdoNetDataAccess.Mapper（引用AdoNetDataAccess.Core）
3、具体数据操作使用层AdoNetDataAccess.Dal（引用AdoNetDataAccess.Mapper）
4、表现层 AdoNetDataAccessWebApp（引用AdoNetDataAccess.Dal）
可以看出，工程里的文件结构还是很清晰的，需要学习的童鞋不妨下载使用试试看吧。