C#2008与.NET 3.5 高级程序设计读书笔记(21)-- 对象序列化
1.对象序列化
术语序列化(serialization)描述了持久化(可能还包括传输)一个对象状态到流(如文件流,内存流)的过程.
当试图通过.NET远程处理层,XML Web服务或WCF这样的远程处理技术将一个对象复制到远程计算机时,具有对类型序列化的能力很关键.
虽然使用.NET序列化保存对象非常简单,但幕后的调用过程却非常复杂.例如,当一个对象被持久化到流时,所有的相关数据(基类,包含的对象等)也会被自动序列化.
2.为序列化配置对象
只需为每个类加上[Serializable]特性,如果要排除某些域,只需在前面加上[NonSerialized]
如:
[Serializable]
public
class
Radio
{
public
bool
hasTweeters;
public
bool
hasSubWoofers;
public
double
[] stationPresets;
[NonSerialized]
public
string
radioID
=
"
XF-552RR6
"
;
}
字段的类型对序列化的影响,如下
代码
[Serializable]
public
class
Person
{
//
公共字段
public
bool
isAlive
=
true
;
//
私有字段
private
int
personAge
=
21
;
//
公共属性/私有数据
private
string
fname
=
string
.Empty;
public
string
FristName
{
get
{
return
fname; }
set
{ fname
=
value; }
}
}
如果由BinaryFormatter或SoapFormatter处理,isAlive,personAge,fname都保存到了所选的流中,然而,XmlSerializer不会保存personAge的值.如果需要使用XmlSerializer序列化,就需要把字段定为公共的.
3.选择何种序列化
当使用BinaryFormatter 类型时,不仅仅是将对象中的字段数据持久化,而且也持久化每个类型的完全限定名称和定义程序集的完整名称(名称,版本,公钥标记,区域),在跨越.NET应用程序边界传递对象时,BinaryFormatter 成为理想的选择.
如果希望持久化的对象图被任意操作系统(Windows,Mac OS,Unix),任何应用程序框架(.NET,J2EE,COM)或编程语言使用,SoapFormatter,XmlSerializer是理想的选择.
4.例子:
代码
[Serializable]
public
class
Car
{
public
Radio theRadio
=
new
Radio();
public
bool
isHatchBack;
}
[Serializable, XmlRoot(Namespace
=
"
http://www.intertech.com
"
)]
public
class
JamesBondCar : Car
{
[XmlAttribute]
public
bool
canFly;
[XmlAttribute]
public
bool
canSubmerge;
public
JamesBondCar(
bool
skyWorthy,
bool
seaWorthy)
{
canFly
=
skyWorthy;
canSubmerge
=
seaWorthy;
}
//
The XmlSerializer demands a default constructor!
public
JamesBondCar() { }
}
[Serializable]
public
class
Radio
{
public
bool
hasTweeters;
public
bool
hasSubWoofers;
public
double
[] stationPresets;
[NonSerialized]
public
string
radioID
=
"
XF-552RR6
"
;
}
class
Program
{
static
void
Main(
string
[] args)
{
Console.WriteLine(
"
***** Fun with Object Serialization *****\n
"
);
//
Make a JamesBondCar and set state.
JamesBondCar jbc
=
new
JamesBondCar();
jbc.canFly
=
true
;
jbc.canSubmerge
=
false
;
jbc.theRadio.stationPresets
=
new
double
[] {
89.3
,
105.1
,
97.1
};
jbc.theRadio.hasTweeters
=
true
;
//
Now save / Load the car to a specific file.
SaveAsBinaryFormat(jbc,
"
CarData.dat
"
);
LoadFromBinaryFile(
"
CarData.dat
"
);
SaveAsSoapFormat(jbc,
"
CarData.soap
"
);
SaveAsXmlFormat(jbc,
"
CarData.xml
"
);
SaveListOfCars();
SaveListOfCarsAsBinary();
Console.ReadLine();
}
#region
Save / Load as Binary Format
static
void
SaveAsBinaryFormat(
object
objGraph,
string
fileName)
{
//
Save object to a file named CarData.dat in binary.
BinaryFormatter binFormat
=
new
BinaryFormatter();
using
(Stream fStream
=
new
FileStream(fileName,
FileMode.Create, FileAccess.Write, FileShare.None))
{
binFormat.Serialize(fStream, objGraph);
}
Console.WriteLine(
"
=> Saved car in binary format!
"
);
}
static
void
LoadFromBinaryFile(
string
fileName)
{
BinaryFormatter binFormat
=
new
BinaryFormatter();
//
Read the JamesBondCar from the binary file.
using
(Stream fStream
=
File.OpenRead(fileName))
{
JamesBondCar carFromDisk
=
(JamesBondCar)binFormat.Deserialize(fStream);
Console.WriteLine(
"
Can this car fly? : {0}
"
, carFromDisk.canFly);
}
}
#endregion
#region
Save as SOAP Format
//
Be sure to import System.Runtime.Serialization.Formatters.Soap
//
and reference System.Runtime.Serialization.Formatters.Soap.dll.
static
void
SaveAsSoapFormat(
object
objGraph,
string
fileName)
{
//
Save object to a file named CarData.soap in SOAP format.
SoapFormatter soapFormat
=
new
SoapFormatter();
using
(Stream fStream
=
new
FileStream(fileName,
FileMode.Create, FileAccess.Write, FileShare.None))
{
soapFormat.Serialize(fStream, objGraph);
}
Console.WriteLine(
"
=> Saved car in SOAP format!
"
);
}
#endregion
#region
Save as XML Format
static
void
SaveAsXmlFormat(
object
objGraph,
string
fileName)
{
//
Save object to a file named CarData.xml in XML format.
XmlSerializer xmlFormat
=
new
XmlSerializer(
typeof
(JamesBondCar),
new
Type[] {
typeof
(Radio),
typeof
(Car) });
using
(Stream fStream
=
new
FileStream(fileName,
FileMode.Create, FileAccess.Write, FileShare.None))
{
xmlFormat.Serialize(fStream, objGraph);
}
Console.WriteLine(
"
=> Saved car in XML format!
"
);
}
#endregion
#region
Save collection of cars
static
void
SaveListOfCars()
{
//
Now persist a List<> of JamesBondCars.
List
<
JamesBondCar
>
myCars
=
new
List
<
JamesBondCar
>
();
myCars.Add(
new
JamesBondCar(
true
,
true
));
myCars.Add(
new
JamesBondCar(
true
,
false
));
myCars.Add(
new
JamesBondCar(
false
,
true
));
myCars.Add(
new
JamesBondCar(
false
,
false
));
using
(Stream fStream
=
new
FileStream(
"
CarCollection.xml
"
,
FileMode.Create, FileAccess.Write, FileShare.None))
{
XmlSerializer xmlFormat
=
new
XmlSerializer(
typeof
(List
<
JamesBondCar
>
),
new
Type[] {
typeof
(JamesBondCar),
typeof
(Car),
typeof
(Radio) });
xmlFormat.Serialize(fStream, myCars);
}
Console.WriteLine(
"
=> Saved list of cars!
"
);
}
static
void
SaveListOfCarsAsBinary()
{
//
Save ArrayList object (myCars) as binary.
List
<
JamesBondCar
>
myCars
=
new
List
<
JamesBondCar
>
();
BinaryFormatter binFormat
=
new
BinaryFormatter();
using
(Stream fStream
=
new
FileStream(
"
AllMyCars.dat
"
,
FileMode.Create, FileAccess.Write, FileShare.None))
{
binFormat.Serialize(fStream, myCars);
}
Console.WriteLine(
"
=> Saved list of cars in binary!
"
);
}
#endregion
}