序列化、反序列化对象常用的两种方式
目录
序列化和反序列化对象常用的两种方式
序列化是使用指定的格式将一个或多个对象转换为字节序列的过程。反序列化则是相反的过程。
我们这里记录2个常用的序列化和反序列化方法。
1、序列化为XML
2、系列化为JSON
一、序列化和反序列化XML
1.1、序列化XML
创建一个WPF程序。
新建一个类文件命名为Person，同时我们引用以下名称空间，创建Person的类中的属性，
使用[XmlAtribute("fname")]属性，会把按当前类属性从子节点变为当前节点的属性，文件大小就变小了。可以尝试一下去掉和不去掉之后产生的XML是否一样。
using System; //DateTime
using System.Collections.Generic; //List<T>,HashSet<T>
using System.Xml.Serialization; //XmlSerializer
namespace SerializationAndDeserialization
{
public class Person
{
public Person()
{
}
public Person(decimal initialSalary)
{
Salary = initialSalary;
}
[XmlAttribute("fname")]
public string FirstName { get; set; }
[XmlAttribute("lname")]
public string LastName { get; set; }
[XmlAttribute("dob")]
public DateTime DateOfBirth { get; set; }
public HashSet<Person> Children { get; set; }
protected decimal Salary { get; set; }
}
}
在MainWindow.cs文件中我们在构造函数中实例化Person。序列化到文件中，然后再反序列化回来。同时我们观察使用XmlAttribute和不使用XmlAttribute有什么差别、观察属性定义为public类型和protected类型再序列化和反序列化过程中有什么不同。
using System;
using System.Collections.Generic;
using System.Xml.Serialization;
using System.IO;
using System.Windows;
using static System.Console;
using static System.Environment;
using static System.IO.Path;
namespace SerializationAndDeserialization
{
/// <summary>
/// MainWindow.xaml 的交互逻辑
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
var people = new List<Person>()
{
new Person(30000M){ FirstName="Alice",LastName="Smith",DateOfBirth=new DateTime(1974,3,14)},
new Person(40000M){ FirstName="Bob",LastName="Jone",DateOfBirth=new DateTime(1969,11,23)},
new Person(20000M){ FirstName="Charlie",LastName="Cox",DateOfBirth=new DateTime(1984,5,4),Children=new HashSet<Person>{ new Person(0M)
{ FirstName="Sally",LastName="Cox",DateOfBirth=new DateTime(2000,7,12)} } }
};
var xs = new XmlSerializer(typeof(List<Person>));
string path = Combine(CurrentDirectory, "pepple.xaml");
using (FileStream stream = File.Create(path))
{
xs.Serialize(stream, people);
}
WriteLine("Witeten {0:N0} bytes of XML to {1}", arg0: new FileInfo(path).Length, arg1: path);
WriteLine();
WriteLine(File.ReadAllText(path));
//系列化文件中不包含Salary，因为是Protected类型。
//引用System.Xml.Serialization后使用[XmlAtribute("fname")]添加特性。文件结构就改变了，同时文件变小了。
}
}
}
左边是不使用再类属性上添加 [XmlAttribute("")]的方法生成的xml文件。右侧是使用 [XmlAttribute("")]属性。右侧文件小了很多。
1.2、反序列化XML
我们现在反序列化这个XML文件。
我们添加代码后完整代码如下：
using System;
using System.Collections.Generic;
using System.Xml.Serialization;
using System.IO;
using System.Windows;
using static System.Console;
using static System.Environment;
using static System.IO.Path;
namespace SerializationAndDeserialization
{
/// <summary>
/// MainWindow.xaml 的交互逻辑
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
var people = new List<Person>()
{
new Person(30000M){ FirstName="Alice",LastName="Smith",DateOfBirth=new DateTime(1974,3,14)},
new Person(40000M){ FirstName="Bob",LastName="Jone",DateOfBirth=new DateTime(1969,11,23)},
new Person(20000M){ FirstName="Charlie",LastName="Cox",DateOfBirth=new DateTime(1984,5,4),Children=new HashSet<Person>{ new Person(0M)
{ FirstName="Sally",LastName="Cox",DateOfBirth=new DateTime(2000,7,12)} } }
};
var xs = new XmlSerializer(typeof(List<Person>));
string path = Combine(CurrentDirectory, "pepple.xaml");
using (FileStream stream = File.Create(path))
{
xs.Serialize(stream, people);
}
WriteLine("Witeten {0:N0} bytes of XML to {1}", arg0: new FileInfo(path).Length, arg1: path);
WriteLine();
WriteLine(File.ReadAllText(path));
//系列化文件中不包含Salary，因为是Protected类型。
//引用System.Xml.Serialization后使用[XmlAtribute("fname")]添加特性。文件结构就改变了，同时文件变小了。
//反序列化
using (FileStream xmlLoad = File.Open(path, FileMode.Open))
{
var loadedPeople = (List<Person>)xs.Deserialize(xmlLoad);
foreach (var item in loadedPeople)
{
WriteLine($"{item.LastName} has {item.Children.Count} children.");
}
}
}
}
}
点击运行，我们观察VS的输出中这三行Log。我们的反序列化就完成了。
Smith has 0 children.
Jone has 0 children.
Cox has 1 children.
二、序列化和反序列化JSON
使用JSON序列化格式的最流行的.NET库之一是Newtonsoft.Json，又名Json.NET。
我们再项目右键点击弹出菜单中选择管理NuGet包，点击浏览输入Newtonsoft.Json。选中找到的Newtonsoft.Json，点击安装。
2.1、尝试序列化信息为JSON，并存放到文本文件中。
我们再后面添加如下代码
using System;
using System.Collections.Generic;
using System.Xml.Serialization;
using System.IO;
using System.Windows;
using static System.Console;
using static System.Environment;
using static System.IO.Path;
namespace SerializationAndDeserialization
{
/// <summary>
/// MainWindow.xaml 的交互逻辑
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
var people = new List<Person>()
{
new Person(30000M){ FirstName="Alice",LastName="Smith",DateOfBirth=new DateTime(1974,3,14)},
new Person(40000M){ FirstName="Bob",LastName="Jone",DateOfBirth=new DateTime(1969,11,23)},
new Person(20000M){ FirstName="Charlie",LastName="Cox",DateOfBirth=new DateTime(1984,5,4),Children=new HashSet<Person>{ new Person(0M)
{ FirstName="Sally",LastName="Cox",DateOfBirth=new DateTime(2000,7,12)} } }
};
var xs = new XmlSerializer(typeof(List<Person>));
string path = Combine(CurrentDirectory, "pepple.xaml");
using (FileStream stream = File.Create(path))
{
xs.Serialize(stream, people);
}
WriteLine("Witeten {0:N0} bytes of XML to {1}", arg0: new FileInfo(path).Length, arg1: path);
WriteLine();
WriteLine(File.ReadAllText(path));
//系列化文件中不包含Salary，因为是Protected类型。
//引用System.Xml.Serialization后使用[XmlAtribute("fname")]添加特性。文件结构就改变了，同时文件变小了。
//反序列化
using (FileStream xmlLoad = File.Open(path, FileMode.Open))
{
var loadedPeople = (List<Person>)xs.Deserialize(xmlLoad);
foreach (var item in loadedPeople)
{
WriteLine($"{item.LastName} has {item.Children.Count} children.");
}
}
//序列化JSON
string jsonPath = Combine(CurrentDirectory, "prople.json");
using (StreamWriter jsonStream = File.CreateText(jsonPath))
{
var jss = new Newtonsoft.Json.JsonSerializer();
jss.Serialize(jsonStream, people);
}
WriteLine();
WriteLine($"Written {new FileInfo(jsonPath).Length} bytes of JSON to :{jsonPath}");
WriteLine(File.ReadAllText(jsonPath));
}
}
}
调试运行输出找到Log关键行如下。
Written 365 bytes of JSON to :E:C#NotesWPF技巧SerializationAndDeserializationSerializationAndDeserializationinDebugprople.json
[{"FirstName":"Alice","LastName":"Smith","DateOfBirth":"1974-03-14T00:00:00","Children":null},{"FirstName":"Bob","LastName":"Jone","DateOfBirth":"1969-11-23T00:00:00","Children":null},{"FirstName":"Charlie","LastName":"Cox","DateOfBirth":"1984-05-04T00:00:00","Children":[{"FirstName":"Sally","LastName":"Cox","DateOfBirth":"2000-07-12T00:00:00","Children":null}]}]
2.2反序列化JSON文件为对象
反序列化的过程，我们使用File读取文件内容，然后使用JsonConvert.DeserializeObject 来反序列化到对象。具体代码如下：
using System;
using System.Collections.Generic;
using System.Xml.Serialization;
using System.IO;
using System.Windows;
using static System.Console;
using static System.Environment;
using static System.IO.Path;
using Newtonsoft.Json;
using System.Runtime.Serialization.Formatters.Binary;
using System.Diagnostics;
namespace SerializationAndDeserialization
{
/// <summary>
/// MainWindow.xaml 的交互逻辑
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
var people = new List<Person>()
{
new Person(30000M){ FirstName="Alice",LastName="Smith",DateOfBirth=new DateTime(1974,3,14)},
new Person(40000M){ FirstName="Bob",LastName="Jone",DateOfBirth=new DateTime(1969,11,23)},
new Person(20000M){ FirstName="Charlie",LastName="Cox",DateOfBirth=new DateTime(1984,5,4),Children=new HashSet<Person>{ new Person(0M)
{ FirstName="Sally",LastName="Cox",DateOfBirth=new DateTime(2000,7,12)} } }
};
//序列化XML
var xs = new XmlSerializer(typeof(List<Person>));
string path = Combine(CurrentDirectory, "pepple.xaml");
using (FileStream stream = File.Create(path))
{
xs.Serialize(stream, people);
}
WriteLine("Witeten {0:N0} bytes of XML to {1}", arg0: new FileInfo(path).Length, arg1: path);
WriteLine();
WriteLine(File.ReadAllText(path));
//系列化文件中不包含Salary，因为是Protected类型。
//引用System.Xml.Serialization后使用[XmlAtribute("fname")]添加特性。文件结构就改变了，同时文件变小了。
//反序列化XML
using (FileStream xmlLoad = File.Open(path, FileMode.Open))
{
var loadedPeople = (List<Person>)xs.Deserialize(xmlLoad);
foreach (var item in loadedPeople)
{
WriteLine($"{item.LastName} has {item.Children.Count} children.");
}
}
//序列化JSON
string jsonPath = Combine(CurrentDirectory, "prople.json");
using (StreamWriter jsonStream = File.CreateText(jsonPath))
{
var jss = new Newtonsoft.Json.JsonSerializer();
jss.Serialize(jsonStream, people);
}
WriteLine();
WriteLine($"Written {new FileInfo(jsonPath).Length} bytes of JSON to :{jsonPath}");
//反序列化JSON
var jsonStr = File.ReadAllText(jsonPath);
WriteLine(File.ReadAllText(jsonPath));
var persons = JsonConvert.DeserializeObject<List<Person>>(jsonStr);
foreach (var item in persons)
{
Debug.WriteLine(item.ToString());
}
}
}
}
再Person中重写ToString()方法用于再反序列化结束后打印输出内容。
using System; //DateTime
using System.Collections.Generic; //List<T>,HashSet<T>
using System.Xml.Serialization; //XmlSerializer
namespace SerializationAndDeserialization
{
public class Person
{
public Person()
{
}
public Person(decimal initialSalary)
{
Salary = initialSalary;
}
[XmlAttribute("fname")]
public string FirstName { get; set; }
[XmlAttribute("lname")]
public string LastName { get; set; }
[XmlAttribute("dob")]
public DateTime DateOfBirth { get; set; }
public HashSet<Person> Children { get; set; }
protected decimal Salary { get; set; }
public override string ToString()
{
return $"FirstName:{FirstName},LastName:{LastName},DateOfBirth:{DateOfBirth}";
}
}
}
整体代码如上，序列化xml和反序列化xml，序列化json和反序列化json都再上面。适用于NET Core之前的版本。Net Core之后的有System.Text.Json对象。