C#，来一个用文本存对象的轮子 - Supper_litt - 开发者的网上家园

　　前言

　　　　看了大家都在造轮子，我也要写一个站点自用了，没有数据库怎么办，又不想用Sqlite，所以自己造吧。大不了就是都文件到内存，然后内存到文件。

　　正文

　　　　对于这种操作，无非就是反射一下属性，然后通过对象和属性进行更新。当然EF也有这样的功能，不过对Model而言太臃肿了，这里就不用了。

　　上代码

　　　　

 1  /// <summary> 2  /// 文件系统数据库 3  /// 主键Attribute [Key]，支持主键比较 4  /// </summary> 5  /// <typeparam name="T"></typeparam> 6  public class FileDbHelper<T> where T : class 7  { 8   private static List<T> dataList = new List<T>(); 9   private static string savePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "App_Data", typeof(T).Name + ".mydb"); 10   private static JavaScriptSerializer js = new JavaScriptSerializer(); 11  12   static FileDbHelper() 13   { 14    string dir = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "App_Data"); 15    if (!Directory.Exists(dir)) 16    { 17     Directory.CreateDirectory(dir); 18    } 19  20    string savePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "App_Data", typeof(T).Name + ".mydb"); 21    if (File.Exists(savePath)) 22    { 23     string[] lines = File.ReadAllLines(savePath, Encoding.UTF8); 24     foreach (var line in lines) 25     { 26      if (!string.IsNullOrEmpty(line)) 27      { 28       try 29       { 30        dataList.Add(js.Deserialize<T>(line)); 31       } 32       catch { } 33      } 34     } 35    } 36   } 37  38   public static void Add(T model) 39   { 40    lock (dataList) 41    { 42     dataList.Add(model); 43     SaveFile(); 44    } 45   } 46  47   public static void AddList(List<T> list) 48   { 49    lock (dataList) 50    { 51     dataList.AddRange(list); 52     SaveFile(); 53    } 54   } 55  56   public static void AddOrUpdate(T model, params string[] args) 57   { 58    lock (dataList) 59    { 60     List<FileDbInfo> infoList = FindKeyDbList(model); 61     T equalModel = CheckKeyEqual(model, infoList); 62     if (equalModel == null) 63     { 64      Add(model); 65     } 66     else 67     { 68      Update(equalModel, model, args); 69     } 70  71     SaveFile(); 72    } 73   } 74  75   public static T QueryInfo(T model, params string[] args) 76   { 77    lock (dataList) 78    { 79     List<FileDbInfo> infoList = FindArgsDbList(model, args); 80     T equalModel = CheckKeyEqual(model, infoList, args); 81  82     return equalModel; 83    } 84   } 85  86   public static List<T> QueryList(int page, int pageSize, T model, params string[] args) 87   { 88    lock (dataList) 89    { 90     List<FileDbInfo> infoList = FindArgsDbList(model, args); 91     List<T> equalList = CheckArgsEqualList(model, infoList, args); 92  93     return equalList.Skip(pageSize * (page - 1)).Take(pageSize).ToList(); 94    } 95   } 96  97   private static void Update(T oldModel, T newModel, string[] args) 98   { 99    List<string> keyList = ReadKeyName();100    foreach (PropertyInfo pInfo in newModel.GetType().GetProperties())101    {102     if (args.Length > 0)103     {104      if (!args.ToList().Contains(pInfo.Name))105      {106       Object new_value = pInfo.GetValue(newModel, null);107       pInfo.SetValue(oldModel, new_value, null);108      }109     }110     else111     {112      if (!keyList.Contains(pInfo.Name))113      {114       Object new_value = pInfo.GetValue(newModel, null);115       pInfo.SetValue(oldModel, new_value, null);116      }117     }118    }119   }120 121   private static T CheckKeyEqual(T model, List<FileDbInfo> infoList, string[] args = null)122   {123    foreach (var item in dataList)124    {125     bool is_equal = true;126     foreach (var info in infoList)127     {128      if (args == null || (args != null && args.ToList().Contains(info.key)))129      {130       if (ReadString(model, info.key) != ReadString(item, info.key))131       {132        is_equal = false;133        break;134       }135      }136     }137 138     if (is_equal)139     {140      return item;141     }142    }143 144    return null;145   }146 147   private static List<T> CheckArgsEqualList(T model, List<FileDbInfo> infoList, string[] args = null)148   {149    List<T> result = new List<T>();150    foreach (var item in dataList)151    {152     bool is_equal = true;153     foreach (var info in infoList)154     {155      if (args == null || (args != null && args.ToList().Contains(info.key)))156      {157       if (ReadString(model, info.key) != ReadString(item, info.key))158       {159        is_equal = false;160        break;161       }162      }163     }164 165     if (is_equal)166     {167      result.Add(item);168     }169    }170 171    return result;172   }173 174   private static List<FileDbInfo> FindKeyDbList(T model, params string[] args)175   {176    List<string> keyList = ReadKeyName();177    var infoList = new List<FileDbInfo>();178    foreach (var key in keyList)179    {180     if (args == null || (args != null && args.ToList().Contains(key)))181     {182      infoList.Add(new FileDbInfo(key, ReadString(model, key)));183     }184    }185 186    return infoList;187   }188 189   private static List<FileDbInfo> FindArgsDbList(T model, params string[] args)190   {191    List<string> keyList = ReadArgsName();192    var infoList = new List<FileDbInfo>();193    foreach (var key in keyList)194    {195     if (args == null || (args != null && args.ToList().Contains(key)))196     {197      infoList.Add(new FileDbInfo(key, ReadString(model, key)));198     }199    }200 201    return infoList;202   }203 204   private static List<string> ReadKeyName()205   {206    List<string> keyList = new List<string>();207    foreach (var pInfo in typeof(T).GetProperties())208    {209     foreach (var attr in pInfo.GetCustomAttributes(false))210     {211      if (attr.GetType() == typeof(KeyAttribute))212      {213       keyList.Add(pInfo.Name);214      }215     }216    }217 218    if (keyList.Count == 0)219    {220     throw new Exception("未定义主键,通过设置注解来添加主键[Key],目前只支持int和string");221    }222 223    return keyList;224   }225 226   private static List<string> ReadArgsName()227   {228    List<string> keyList = new List<string>();229    foreach (var pInfo in typeof(T).GetProperties())230    {231     keyList.Add(pInfo.Name);232    }233 234    return keyList;235   }236 237   private static string ReadString(T model, string key_name)238   {239    PropertyInfo propertyInfo = model.GetType().GetProperty(key_name);240    object obj = propertyInfo.GetValue(model, null);241    if (propertyInfo.PropertyType == typeof(int))242    {243     return obj.ToString();244    }245    else if (propertyInfo.PropertyType == typeof(string))246    {247     return obj.ToString();248    }249    else250    {251     return obj.ToString();252    }253   }254 255   private static void SaveFile()256   {257    StringBuilder content = new StringBuilder();258    foreach (var item in dataList)259    {260     content.AppendLine(js.Serialize(item));261    }262 263    File.WriteAllText(savePath, content.ToString(), new UTF8Encoding(false));264   }265  }266 267  public class FileDbInfo268  {269   public FileDbInfo(string key, string str_value)270   {271    this.key = key;272    this.str_value = str_value;273   }274 275   public string key { get; set; }276 277   public string str_value { get; set; }278  }279 280  public class KeyAttribute : Attribute { }281 }

　　使用方式。

public class UserInfo2 {  [Key]  public string name { get; set; }  public string pwd { get; set; }  public int age { get; set; }  public string info { get; set; } }

　　　　　　　　// 新增数据
　　　　　　　FileDbHelper<UserInfo2>.AddOrUpdate(new UserInfo2() { name = "test1", pwd = "12341", age = 10 });   FileDbHelper<UserInfo2>.AddOrUpdate(new UserInfo2() { name = "test2", pwd = "12342", age = 10 });   FileDbHelper<UserInfo2>.AddOrUpdate(new UserInfo2() { name = "test3", pwd = "12343", age = 11 });   FileDbHelper<UserInfo2>.AddOrUpdate(new UserInfo2() { name = "test4", pwd = "12344", age = 12 });   FileDbHelper<UserInfo2>.AddOrUpdate(new UserInfo2() { name = "test5", pwd = "12345", age = 10 });
　　　　　　 // 查询集合，条件查询   var list = FileDbHelper<UserInfo2>.QueryList(1, 10, new UserInfo2() { age = 10 }, "age");
  // 单个对象，条件查询   var model = FileDbHelper<UserInfo2>.QueryInfo(new UserInfo2() { age = 12 }, "age");
 // 修改所有值   model.info = "hehe";   FileDbHelper<UserInfo2>.AddOrUpdate(model);
// 修改指定的值   FileDbHelper<UserInfo2>.AddOrUpdate(new UserInfo2() { name = "test1", age = 12 }, "age");   var model2 = FileDbHelper<UserInfo2>.QueryInfo(model);

总结：伟大出自平凡。

原文转载：http://www.shaoqun.com/a/478851.html

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前言　　　　看了大家都在造轮子，我也要写一个站点自用了，没有数据库怎么办，又不想用Sqlite，所以自己造吧。大不了就是都文件到内存，然后内存到文件。　　正文　　　　对于这种操作，无非就是反射一下属性，然后通过对象和属性进行更新。当然EF也有这样的功能，不过对Model而言太臃肿了，这里就不用了。　　上代码　　　　1///<summary>2///文件系统数据库3///主键Attrib
斑马物联：https://www.ikjzd.com/w/1316
克雷格：https://www.ikjzd.com/w/194
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