泛型缓存(Generic)

在 2019-10-21 2019-10-21 发表的泛型当中我们说过一个很重要的点就是不同的泛型类,进入的时候其实在后台的时候创建了不同的类,所以进入的类其实是不同的由此我们可以想想出一种方法来做缓存

 1 namespace YZMDAL
 2 {
 3     public class SQLBuilder<T> where T: BaseModel
 4     {
 5         private static string FindOne = null;
 6         private static string insertSql = null;
 7         private static string updatedb = null; 
 8         private static string Deletesql = null; 
 9         /// <summary>
10         /// 无参构造器
11         /// </summary>
12         static SQLBuilder()
13         {
14             {
15                 Type type = typeof(T);//获取类型
16                 string columnString = string.Join(",", type.GetProperties().Select(x => $"`{x.GetColumnMappingName()}`"));
17                 FindOne = $@"select {columnString} from  `{type.GetMappingName()}` where Id=@id";//type.GetMappingName()特性的语法糖
18             }
19             {
20                 Type type = typeof(T);//获取类型
21                 string columnString = string.Join(",", type.GetProperties().FilterKey().Select(x => $"`{x.GetColumnMappingName()}`"));//出去主键Id
22                 //遍历属性值
23                 string  ValuesString = string.Join(",", type.GetProperties().FilterKey().Select(x => $"@{x.GetColumnMappingName()}"));
24                 insertSql = $@"Insert into `{type.Name}`({columnString}) values({ValuesString})";
25             }
26             {
27                 Type type = typeof(T);
28                 //string Columnsql = string.Join(",", type.GetProperties().FilterKey().Select(x => $"{x.Name}=$'{x.GetValue(t)??DBNull.Value }'"));//为防止sql注入
29                 string Columnsql = string.Join(",", type.GetProperties().FilterKey().Select(x => $"`{x.Name}`=@{x.Name}"));//防止sql注入并使用sqlparament
30                 updatedb = $"UPDATE  `{type.Name}` SET {Columnsql} where Id=@Id ";
31             }
32             {
33                 //delete 方法
34                 Type type = typeof(T);
35                 //string Columnsql = string.Join(",", type.GetProperties().FilterKey().Select(x => $"{x.Name}=$'{x.GetValue(t)??DBNull.Value }'"));//为防止sql注入
36                 string Columnsql = string.Join(",", type.GetProperties().FilterKey().Select(x => $"{x.Name}=@{x.Name}"));//防止sql注入并使用sqlparament
37                 Deletesql = $" delete  from `{type.Name}`  where  Id = @Id ";
38             }
39         }
40 
41         /// <summary>
42         /// 对外提供的接口
43         /// </summary>
44         /// <param name="sqlType"></param>
45         /// <returns></returns>
46         public static string GetSql (sqlType sqlType)
47         {
48             switch (sqlType)
49             {
50                 case sqlType.FindOne:
51                     return FindOne;
52                 case sqlType.insertSql:
53                     return insertSql;
54                 case sqlType.updatedb:
55                     return updatedb;
56                 case sqlType.Delete:
57                     return Deletesql;
58                 default:
59                     throw new Exception("我也不知道该写啥");
60             }
61         }
62         /// <summary>
63         /// 枚举传参
64         /// </summary>
65         public enum sqlType
66         {
67             FindOne  ,
68             insertSql,
69             updatedb,
70             Delete
71         }
72 
73     }
74 }

例如以上代码:当不同的类型进入类的时候其实是进入了无数个复写的类所有的静态方法都是不一样的所缓存的内容也是不一样的而且Static的生命周期是和进程一致的只要进程不中断,当前的static都是不会被回收的由此我我们们可以将不长改动的数据进行缓存

而不用每次进行数据拼接

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