Serialization (serialization)

Serialization is a mechanism provided by Microsoft for file I/O to objects, and the mechanism is well applied in frame/document (documents)/view mode. Many people are not very clear about what serialization is, how to make the object serializable, and how to use the serialization feature. This paper attempts to make a simple explanation of serialization. Because I use the serialization function is not much, the deficiencies please understand.

File reading and writing in MFC Framework/document/view structure

CFile is the base class for all file classes in the MFC class library. All of the file I/O features provided by MFC are related to this class. In many cases, people like to call Cfile::write/writehuge directly to write files, call Cfile::read/readhuge to read files. Such file I/O in fact and do not use MFC file I/O does not differ, even with the previous ANSI C file I/O is not much different, the difference is not only the API of the call.

When you start learning C + +, you must be familiar with cin/cout, which use the very clear << and >> operators for I/O, using the format://示例代码1
int i;
cin >> i;
//here do something to object i
cout << i;

With the benefit of I/O in this way, with operator overloading, you can read and write to a series of objects with a single statement without distinguishing the specific types of objects. MFC provides class CArchive, implements the overloads of operators << and >>, and wants file I/O in front of Cin and cout. In conjunction with the CFile class, not only does the file read and write to the simple type such as int/float, but also the file read and write to the serializable object (Serializable Objects, described later).

In general, the process of reading an object using CArchive is as follows:

//示例代码2
//定义文件对象和文件异常对象
CFile file;
CFileException fe;
//以读方式打开文件
if(!file.Open(filename,CFile::modeRead,&fe))
{
fe.ReportError();
return;
}

//构建CArchive 对象
CArchive ar(&file,CArchive::load);
ar >> obj1>>obj2>>obj3...>>objn;
ar.Flush();
//读完毕，关闭文件流
ar.Close();
file.Close();

The process of writing an object using CArchive is as follows://示例代码3
//定义文件对象和文件异常对象
CFile file;
CFileException fe;
//以读方式打开文件
if(!file.Open(filename,CFile::modeWrite|CFile::modeCreate,&fe))
{
fe.ReportError();
return;
}

//构建CArchive 对象
CArchive ar(&file,CArchive::load);
ar << obj1<<obj2<<obj3...<<objn;
ar.Flush();
//写完毕，关闭文件流
ar.Close();
file.Close();