C#，来一个用文本存对象的轮子

　　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                 else
111                 {
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             else
250             {
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 FileDbInfo
268     {
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。

posted @ 2020-10-03 21:33  Supper_litt  阅读(426)  评论(0)  编辑  收藏  举报