用C#模拟 Java Bean （二）—— SqlPojo

来源：互联网发布：50 seo 编辑：程序博客网时间：2024/05/01 10:44
恩，之前已经展示了一个简单粗暴的 DBHelper 类。
该类不做任何检查就直接操作数据库了。
DBHelper最后出现了直接操作数据库实体对象（SqlPojo）的方法，明显，这需要SqlPojo的支持。
这里描述一下SqlPojo需要对此提供的支持：
自动生成SQL语句，增删改，查的话，暂不考虑
直接自查询结果中加载属性，明显，一个SqlPojo实例对应一个DataRow
啊，C#的注释没太搞清楚，谁能告诉我怎么让注释换行？
最好给个C#注释规则给我参考下。
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Reflection;using System.Collections;using System.Data;/// <summary>/// <br>SqlPojo -- 对应数据库的实体</br>/// <br>模仿 Java 里 Hibernate JavaBean 而制作的虚基类</br>/// </summary>public abstract class SqlPojo{public SqlPojo(){//// TODO: 在此处添加构造函数逻辑//        this.AddTime = DateTime.Now;}    private const string Delimiter = ", ";    private const string SingleTemplate = "Select * From [{0}] Where ({1})";    private const string InsertTemplate = "Insert Into [{0}] ({1}) Values ({2})";    private const string DeleteTemplate = "Delete From [{0}] Where ({1})";    private const string UpdateTemplate = "Update [{0}] Set {1} Where ({2})";    private const string FieldTemplate = "[{0}]";    private const string ValueTemplate = "'{0}'";    private const string SetNullTemplate = "[{0}] = NULL";    private const string SetValueTemplate = "[{0}] = '{1}'";    protected const string KeyTemplate = "[{0}] = '{1}'";    private DateTime _AddTime;    private DateTime _UpdTime;    /// <summary>    /// <br>返回此数据库实体进入数据库时的时间</br>    /// </summary>    public virtual DateTime AddTime    {        get { return _AddTime; }        set { _AddTime = value; }    }    /// <summary>    /// <br>返回此数据库实体的最近一次更新时间</br>    /// </summary>    public virtual DateTime UpdTime    {        get { return _UpdTime; }        set { _UpdTime = value; }    }    /// <summary>    /// <br>返回此类实体对于数据库的主键限定语句</br>    /// <br>例如："Uid = this.Uid"</br>    /// <example>"Oid = this.Oid AND Gid = this.Gid"</example>    /// </summary>    protected abstract string GetKeyCondition();    /// <summary>    /// <br>返回此类实体所属的数据库表</br>    /// <example>"User.Login"</example>    /// </summary>    protected abstract string GetTableName();    /// <summary>    /// <br>返回此实体的默认状态值</br>    /// <br>已放弃使用，因为并不是所有表都需要StatusCode这一列</br>    /// <example value = "1500">1500</example>    /// </summary>    protected int GetDefaultST() { return 0; }    /// <summary>    /// <br>返回此实体所对应的 Insert 语句.</br>    /// <br>注意，添加实体的时候应设定 AddTime 为 Now</br>    /// </summary>    public string ToInsertString()    {        //this._UpdTime = DateTime.Now;        string fieldstr = "";        string valuestr = "";        bool first = true;        foreach (PropertyInfo property in this.GetType().GetProperties())        {            // this.InsertString 也会出现在 this.GetType().GetProperties() 中，从而导致 堆栈溢出，但它是只读的.            // 剔除 只读 的属性            if (property.CanWrite == false) { continue; }            // 剔除 空值 属性 和 零值属性            if (Constants.IsNull(property.GetValue(this))) { continue; }            //            if (first != true)            {                fieldstr += SqlPojo.Delimiter;                valuestr += SqlPojo.Delimiter;            }            fieldstr += string.Format(SqlPojo.FieldTemplate, property.Name);            valuestr += string.Format(SqlPojo.ValueTemplate, property.GetValue(this).ToString());            first = false;        }        return string.Format(SqlPojo.InsertTemplate, this.GetTableName(), fieldstr, valuestr);    }    /// <summary>    /// <br>返回此实体对应的 Delete 语句</br>    /// <br>请确保此时此实体的 GetKeyCondition 可用</br>    /// </summary>    public string ToDeleteString()    {        return string.Format(SqlPojo.DeleteTemplate, this.GetTableName(), this.GetKeyCondition());    }    /// <summary>    /// <br>返回此实体对应的 Update 语句</br>    /// <br>请确保此时此实体的 GetKeyCondition 可用</br>    /// <br>注意，更新的时候将 UpdateTime 设定为 Now</br>    /// </summary>    public string ToUpdateString()    {        //this._UpdTime = DateTime.Now;        string fieldstr = "";        bool first = true;        foreach (PropertyInfo property in this.GetType().GetProperties())        {            // 剔除 只读 的属性            if (property.CanWrite == false) { continue; }            if (first != true) { fieldstr += SqlPojo.Delimiter; }            if (property.GetValue(this) == null)            {                fieldstr += string.Format(SqlPojo.SetNullTemplate, property.Name);            }            else            {                fieldstr += string.Format(SqlPojo.SetValueTemplate, property.Name, property.GetValue(this));            }            first = false;        }        return string.Format(SqlPojo.UpdateTemplate, this.GetTableName(), fieldstr, this.GetKeyCondition());    }    /// <summary>    /// 返回此以 GetKeyCondition() 为条件的查询语句以获取单条记录    /// </summary>    /// <returns></returns>    public string ToSingleString()    {        return string.Format(SqlPojo.SingleTemplate, this.GetTableName(), this.GetKeyCondition());    }    /// <summary>    /// <br>从 Hashtable 中加载属性到实体中</br>    /// </summary>    /// <param name="param">哈希集合</param>    public void LoadFromHashtable(Hashtable param)    {        foreach (PropertyInfo property in this.GetType().GetProperties())        {            // 剔除 只读 的属性            if (property.CanWrite == false) { continue; }            if (param.ContainsKey(property.Name) && param[property.Name] != null)             {                try                {                    Type propertyType = property.PropertyType;                    string s = param[property.Name].ToString();                    if (propertyType == typeof(string))                    {                        property.SetValue(this, s);                    }                    else if (propertyType == typeof(long))                    {                        property.SetValue(this, long.Parse(s));                    }                    else if (propertyType == typeof(int))                    {                        property.SetValue(this, int.Parse(s));                    }                    else if (propertyType == typeof(bool))                    {                        property.SetValue(this, bool.Parse(s));                    }                    else if (propertyType == typeof(DateTime))                    {                        property.SetValue(this, DateTime.Parse(s));                    }                }                catch (Exception e)                {                    Console.WriteLine(e.Message);                }            }        }    }    public void LoadFromDataRow(DataRow dr)    {        foreach (PropertyInfo property in this.GetType().GetProperties())        {            if (property.CanWrite == false) { continue; }            if(dr.Table.Columns.Contains(property.Name))            {                if(dr[property.Name] is System.DBNull)                {                    property.SetValue(this, null);                }                else                {                    property.SetValue(this, dr[property.Name]);                }            }        }    }    public override string ToString()    {        Type tp = this.GetType();        return this.GetType().Name;    }}
啊，发现有些注释是旧的，额，应该没关系，大家能理解就行。
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