一、 使用序列化类
序列化一个类,并通过网络传输需要三步:
1、将要序列化的类创建成一个library对象。
2、编写一个发送程序来创建要序列化类的实例,并发送。
3、编写一个接收程序从流中读取数据,并重新创建原来的序列化类。
① 编写要序列化的类
每个要通过网络传输数据的类必须在原代码文件里使用[Serializable]标签。这表明,类中所有的数据在传输时都将要被序列化。下面展示了如何创建一个可以序列化的类。
using System;
[Serializable] public class SerialEmployee { public int EmployeeID public string LastName;
public string FirstName;
public int YearsService;
public double Salary;
public SerialEmployee() { EmployeeID = 0;
LastName = null; FirstName = null;
YearsService = 0; Salary = 0.0; } }
为了使用该类来传输数据,必须现创建一个library文件: csc /t:library SerialEmployee.cs
② 编写一个传输程序
创建数据类以后,可以创建一个程序来传输数据。可以使用BinaryFormatter和SoapFormatter类来序列化数据。
BinaryFormatter将数据序列化为二进制流。通常在实际数据中,增加一些信息,例如类名和版本号信息。
也可以使用SoapFormatter类使用XML格式来传输数据。使用XML的好处就是可以在任何系统和程序间传递数据。
第一必须创建一个流的实例来传递数据。可以是任何类型的流,包括FileStream,MemoryStream,NetworkStream。然后,可以创建一个序列化类,使用Serialize()方法来通过流对象传递数据:
Stream str = new FileStream( "testfile.bin", FileMode.Create, FileAccess.ReadWrite); IFormatter formatter = new BinaryFormatter(); formatter.Serialize(str, data); Iformatter类创建了一个用来序列化的类的实例(BinaryFormatter或者SoapFormatter),使用Serialize()类来将数据序列化
using System;
using System.IO;
using System.Runtime.Serialization; using System.Runtime.Serialization.Formatters.Soap; class SoapTest { public static void Main() { SerialEmployee emp1 = new SerialEmployee();
SerialEmployee emp2 = new SerialEmployee();
emp1.EmployeeID = 1;
emp1.LastName = "Blum";
emp1.FirstName = "Katie Jane";
emp1.YearsService = 12;
emp1.Salary = 35000.50;
emp2.EmployeeID = 2;
emp2.LastName = "Blum";
emp2.FirstName = "Jessica";
emp2.YearsService = 9;
emp2.Salary = 23700.30;
Stream str = new FileStream("soaptest.xml", FileMode.Create, FileAccess.ReadWrite); IFormatter formatter = new SoapFormatter();
formatter.Serialize(str, emp1);
formatter.Serialize(str, emp2); str.Close(); } }
SoapFormatter类包含在System.Runtime.Serialization.Formatters.Soap命名空间,BinaryFormatter类包含在System.Runtime.Serialization.Formatters.Binary命名空间,Iformatter接口包含在System.Runtime.Serialization命名空间。
编译代码:CSC /r:SerialEmployee.dll SoapTest.cs
运行SoapTest.exe程序后,可以查看产生的soaptest.xml文件
1 Blum Katie Jane 12 35000.5 2 Blum Jessica 9 23700.3
查看soaptest.xml文件,我们可以发现在序列化类中SOAP是如何定义每个数据元素。一个值得注意的重要XML数据特点如下:
"http://schemas.microsoft.com/clr/assem/SerialEmployee%2C%20Version%3D0.Â0.0.0.%2C%20Culture%3Dneutral%2C%20PublicKeyToken%3Dnull">
这里,XML中定义的数据使用了序列化数据类的实际类名。如果接收程序使用了另一个不同的类名,会和从流中读取的XML数据不匹配。类不匹配,读取将会失败。
下面的代码展示了如何序列化数据,将数据传送到远程系统。
using System;
using System.Net;
using System.Net.Sockets;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;
class BinaryDataSender { public static void Main() { SerialEmployee emp1 = new SerialEmployee();
SerialEmployee emp2 = new SerialEmployee();
emp1.EmployeeID = 1;
emp1.LastName = "Blum";
emp1.FirstName = "Katie Jane";
emp1.YearsService = 12;
emp1.Salary = 35000.50;
emp2.EmployeeID = 2;
emp2.LastName = "Blum";
emp2.FirstName = "Jessica";
emp2.YearsService = 9;
emp2.Salary = 23700.30;
TcpClient client = new TcpClient("127.0.0.1", 9050);
IFormatter formatter = new BinaryFormatter();
NetworkStream strm = client.GetStream();
formatter.Serialize(strm, emp1);
formatter.Serialize(strm, emp2);
strm.Close();
client.Close(); } }
因为BinaryFormatter和SoapFormatter类需要一个Stream对象来传递序列化的数据,所以要使用一个TCP Socket对象或者一个TcpClient对象来传递数据,不能直接使用UDP。
③编写一个接收程序
using System;
using System.Net;
using System.Net.Sockets;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;
class BinaryDataRcvr { public static void Main() { TcpListener server = new TcpListener(9050);
server.Start();
TcpClient client = server.AcceptTcpClient();
NetworkStream strm = client.GetStream();
IFormatter formatter = new BinaryFormatter();
SerialEmployee emp1 = (SerialEmployee)formatter.Deserialize(strm); Console.WriteLine("emp1.EmployeeID = {0}", emp1.EmployeeID); Console.WriteLine("emp1.LastName = {0}", emp1.LastName); Console.WriteLine("emp1.FirstName = {0}", emp1.FirstName); Console.WriteLine("emp1.YearsService = {0}", emp1.YearsService); Console.WriteLine("emp1.Salary = {0}\n", emp1.Salary); SerialEmployee emp2 = (SerialEmployee)formatter.Deserialize(strm); Console.WriteLine("emp2.EmployeeID = {0}", emp2.EmployeeID); Console.WriteLine("emp2.LastName = {0}", emp2.LastName); Console.WriteLine("emp2.FirstName = {0}", emp2.FirstName); Console.WriteLine("emp2.YearsService = {0}", emp2.YearsService); Console.WriteLine("emp2.Salary = {0}", emp2.Salary); strm.Close(); server.Stop(); } } Winxp系统:c:\Windows c:\Windows\system32
二、 程序改进
在前面的程序中有一个假设:发送者的所有数据都被接收者接收。如果数据丢失,调用Deserialize()方法会发生错误。一个简单的解决方法是将序列化数据放到MemoryStream对象中。MemoryStream对象将所有的序列化数据保存在内存中,可以很容易得到序列化数据的大小。当传递数据时,将数据大小和数据一起传递。
using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Soap;
class BetterDataSender { public void SendData (NetworkStream strm, SerialEmployee emp) { IFormatter formatter = new SoapFormatter(); MemoryStream memstrm = new MemoryStream();
formatter.Serialize(memstrm, emp);
byte[] data = memstrm.GetBuffer();
int memsize = (int)memstrm.Length;
byte[] size = BitConverter.GetBytes(memsize);
strm.Write(size, 0, 4); strm.Write(data, 0, memsize); strm.Flush();
memstrm.Close(); } public BetterDataSender() { SerialEmployee emp1 = new SerialEmployee();
SerialEmployee emp2 = new SerialEmployee();
emp1.EmployeeID = 1; emp1.LastName = "Blum";
emp1.FirstName = "Katie Jane";
emp1.YearsService = 12;
emp1.Salary = 35000.50;
emp2.EmployeeID = 2;
emp2.LastName = "Blum";
emp2.FirstName = "Jessica";
emp2.YearsService = 9;
emp2.Salary = 23700.30;
TcpClient client = new TcpClient("127.0.0.1", 9050);
NetworkStream strm = client.GetStream();
SendData(strm, emp1);
SendData(strm, emp2);
strm.Close(); client.Close(); } public static void Main() { BetterDataSender bds = new BetterDataSender(); } } 接收数据程序如下:
using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Soap;
class BetterDataRcvr { private SerialEmployee RecvData (NetworkStream strm) { MemoryStream memstrm = new MemoryStream();
byte[] data = new byte[4]; int recv = strm.Read(data, 0, 4);
int size = BitConverter.ToInt32(data, 0);
int offset = 0;
while(size > 0) { data = new byte[1024];
recv = strm.Read(data, 0, size);
memstrm.Write(data, offset, recv);
offset += recv; size -= recv; } IFormatter formatter = new SoapFormatter(); memstrm.Position = 0;
SerialEmployee emp = (SerialEmployee)formatter.Deserialize(memstrm);
memstrm.Close();
return emp; } public BetterDataRcvr() { TcpListener server = new TcpListener(9050);
server.Start();
TcpClient client = server.AcceptTcpClient();
NetworkStream strm = client.GetStream();
SerialEmployee emp1 = RecvData(strm);
Console.WriteLine("emp1.EmployeeID = {0}", emp1.EmployeeID); Console.WriteLine("emp1.LastName = {0}", emp1.LastName); Console.WriteLine("emp1.FirstName = {0}", emp1.FirstName); Console.WriteLine("emp1.YearsService = {0}", emp1.YearsService); Console.WriteLine("emp1.Salary = {0}\n", emp1.Salary); SerialEmployee emp2 = RecvData(strm); Console.WriteLine("emp2.EmployeeID = {0}", emp2.EmployeeID); Console.WriteLine("emp2.LastName = {0}", emp2.LastName); Console.WriteLine("emp2.FirstName = {0}", emp2.FirstName); Console.WriteLine("emp2.YearsService = {0}", emp2.YearsService); Console.WriteLine("emp2.Salary = {0}", emp2.Salary); strm.Close(); server.Stop(); } public static void Main() { BetterDataRcvr bdr = new BetterDataRcvr(); } }
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