8.1 文件
8.1.1 不同视角下的文件
应用程序级,人类可阅读级,机器级
8.1.2 位,字节和字节数组
8.2 流
8.2.1 关于流的类比
8.2.2 使用流进行文件复制
1.一次性复制
2.循环分批复制
当打开或创建文件时,流指针默认位于文件头,当调用read或write方法后,流指针会自动向后移动相应的字节。因此在代码中无需设置,每次调用read或write时,读取的都是未处理的字节。
8.2.3 流的类型体系
1.基础流
从流中读取数据:canread;read;readbyte
向流中写入数据:canwrite;write;writebyte
移动流指针:canseek;seek;position;close;dispose;flush;
超时处理:cantimeout;readtimeout;writetimeout;
流长度:length;setlength
2.装饰器流
1)包含stream流基类的引用
2)没有后备存储概念
bufferedstream;deflatestream;gzipstream
3.包装器类
1)streamreader和streamwriter
2)binaryreader和binarywriter
4.帮助类
file静态类:open;openwrite;openread;readalltext;readallbytes;writeallbytes;writealllines;copy
fileinfo;path;directory;dicrectoryinfo
8.3 序列化
8.3.1 基本操作
IFormatter:serialize;deserialize
binaryformatter和soapformatter
默认情况下类型都是不可序列化的,需要明确指出[Serializable]特性(133)
序列化不光需要该类型是标记为Serializable,类型中的属性和字段也需要是可序列化的。如不需要序列化,用[NonSerialized]特性标记,该特性只能加在字段上,不能加在属性上(134)
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Collections; using System.IO; using System.Data.SqlClient; using System.Runtime.Serialization; using System.Runtime.Serialization.Formatters.Binary; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { Product product = new Product(188) { Price = 4998.5F, Name = "Lumia 920" }; IFormatter formatter = new BinaryFormatter(); Stream fs = File.OpenWrite(@"C:\Users\Administrator\Desktop\product.obj"); formatter.Serialize(fs, product); fs.Dispose(); Console.WriteLine(product); //IFormatter formatter = new BinaryFormatter(); //Stream fs = File.OpenRead(@"C:\Users\Administrator\Desktop\product.obj"); //Product product = (Product)formatter.Deserialize(fs); //fs.Dispose(); //Console.WriteLine(product); Console.Read(); } [Serializable] public class Product:IDeserializationCallback { private int id; public string Name { get; set; } public double Price { get; set; } [NonSerialized] private SqlConnection conn; public Product(int id) { this.id = id; conn = new SqlConnection(@"Data Source=.;Initial Catalog=DB;User ID=sa;Password=123"); } public override string ToString() { return string.Format("id:{0},name:{1},price:{2},conn:{3}", this.id, this.Name, this.Price, this.conn == null ? "NULL" : "OBJECT"); } public void OnDeserialization(object sender) { conn = new SqlConnection(@"Data Source=.;Initial Catalog=DB;User ID=sa;Password=123"); } } } }
8.3.2 事件响应
[OnSerializing]
[OnSerialized]
[OnDeserializing]
[OnDeserialized]
四个特性对应四个事件方法
8.3.3 自定义序列化过程