8. Serialization and deserialization technology
Serialization and deserialization are the processes of converting an object’s state in memory into a format that can be stored or transmitted, and converting stored or transmitted data back into an object.
Serialization converts an object into a sequence of bytes or other form of data so that it can be stored in a file, database, or transmitted over a network. During the serialization process, the object’s data is encoded into a byte stream or other representation according to certain rules and formats. This saves the state of the object so that it can be restored at a later point in time or transferred to other systems.
Deserialization is the process of restoring a sequence of bytes or other forms of data to an object according to the rules and formats used in the serialization process. During deserialization, data is read from a byte stream or other representation and decoded into a memory representation of an object in a prescribed format for use in a program.
Through serialization and deserialization, the following functions can be achieved:
- Persistent storage of objects: After serializing the object into a byte sequence, it can be saved to disk or database, so that the state of the object can be persisted.
- Inter-process communication: Through serialization and deserialization, objects can be transferred between different processes, so that different components in a distributed system can exchange data with each other.
- Remote calls: Serialization and deserialization can be used for remote procedure calls (RPC), where objects are serialized and deserialized between the client and the server to implement method calls across the network.
Common serialization and deserialization technologies include JSON, XML, Protocol Buffers, MessagePack, etc., which provide different rules and formats for object serialization and deserialization operations.
8.1 C language serialization and deserialization
In C language, you can use the following techniques for serialization and deserialization:
1. Structure assignment: Copy the data in the structure to the byte sequence one by one, and then restore it to the structure one by one by reading. This method is simple and straightforward, but requires the definition and order of the structures to be consistent.
2. Customized byte stream: Serialization and deserialization through pointer and byte operations. Data can be read and written through pointers, and data can be stored or read into a byte sequence one by one in the form of bytes. During deserialization, bytes are read sequentially and converted to the corresponding data type.
3. Standard library functions: The standard library of C language provides some functions to assist in serialization and deserialization operations, such as `fread` and `fwrite` functions. These functions can directly read or write a specified size of data to a file or buffer. You can use these functions to serialize and deserialize structures or other data.
4. Third-party libraries: There are also some third-party libraries that provide higher-level serialization and deserialization functions, such as Google’s Protocol Buffers library, msgpack-c library, etc. These libraries provide richer functions and more efficient serialization strategies, making it easy to serialize and deserialize complex data structures.
No matter what technology is used, the serialization and deserialization processes need to ensure the correctness, integrity and compatibility of the data. It is also necessary to pay attention to the handling of byte order, as well as issues such as cross-platform and version compatibility, to ensure that serialized data can be deserialized correctly in different environments.
8.2 Other uses of serialization and deserialization
Serialization and deserialization are
The process of converting objects into byte sequences for storage or transmission, and converting byte sequences into objects. This technique is commonly used in distributed systems, persistent storage, and network communications. Here are several common serialization and deserialization techniques:
1. JSON (JavaScript Object Notation): JSON is a lightweight data exchange format commonly used in web applications. Objects can be serialized to strings via JSON and then restored back to objects via deserialization. Most programming languages provide JSON serialization and deserialization libraries.
2. XML (eXtensible Markup Language): XML is a commonly used markup language that can represent complex document structures and data. XML serialization can convert objects into text in XML format, and then re-convert the XML text into objects through deserialization. Many programming languages have built-in XML serialization and deserialization libraries.
3. Protocol Buffers: Protocol Buffers is a binary serialization format developed by Google. It uses a simple interface description language to define the data structure, and then generates the corresponding serialization and deserialization code through the compiler. Protocol Buffers support serialization and deserialization in multiple programming languages.
4. MessagePack: MessagePack is an efficient binary serialization format that has a smaller size and faster speed. MessagePack can serialize objects into binary format for storage or network transmission, and then restore the binary data to objects through deserialization.
5. Java Serialization: Java serialization is a Java-specific mechanism for converting Java objects into sequences of bytes. It can save objects to a file or transfer them over the network. The Java serialization mechanism is built into the Java language and can implement the `java.io.Serializable` interface on objects to support serialization and deserialization.
These are just some of the serialization and deserialization technologies, there are many other technologies to choose from, suitable for different application scenarios and programming languages. Choosing the appropriate serialization and deserialization technology depends on specific needs and requirements and requires consideration of factors such as performance, readability, compatibility, and security.
8.3 C language code explanation
When it comes to code demonstrations, please provide the specific object types and data you want to serialize and deserialize, as well as the programming language you want to use. This way I can provide you with more specific code examples to demonstrate the serialization and deserialization process. The following is a simple example of using structures for serialization and deserialization in C language:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// Define an example structure
typedef struct {
int id;
char name[20];
float score;
} Student;
// serialization function
void serialize(Student* student, char* buffer) {
memcpy(buffer, student, sizeof(Student));
}
//Deserialization function
void deserialize(char* buffer, Student* student) {
memcpy(student, buffer, sizeof(Student));
}
int main() {
//Create a sample object
Student originalStudent = { 12345, "Alice", 89.5 };
// Serialization process
char serializedData[sizeof(Student)];
serialize( & amp;originalStudent, serializedData);
//Print the serialized data
printf("Serialized Data: ");
for (int i = 0; i < sizeof(Student); i + + ) {
printf(" X ", serializedData[i]);
}
printf("\
");
//Deserialization process
Student deserializedStudent;
deserialize(serializedData, & amp;deserializedStudent);
//Print deserialized object information
printf("Deserialized Student:\
");
printf("ID: %d\
", deserializedStudent.id);
printf("Name: %s\
", deserializedStudent.name);
printf("Score: %.1f\
", deserializedStudent.score);
return 0;
}
In the above example, we defined a structure called `Student`, which contains the student’s ID, name and score. The `serialize` function converts a `Student` object into a byte sequence, and the `memcpy` function copies the structure to the buffer by bytes. The `deserialize` function copies the byte sequence back to the memory space occupied by the `Student` object.
In the `main` function, we create a sample `Student` object and demonstrate serialization and deserialization. First, we serialize the original `Student` object into a sequence of bytes and print out the serialized data. Then, we deserialize the byte sequence into a new Student object and print out the deserialized object information.
Output example: //FFFFFFB3 42 The 64-bit computer output seems to be FFFFFFB3
Serialized Data: C9 00 00 00 41 6C 69 63 65 00 00 00 00 00 00 00 00 00 00 00 94 42 Deserialized Student:
ID: 12345
Name: Alice
Score: 89.5
This example shows how to serialize and deserialize objects through structures. In actual applications, you may need to process more complex data structures, use different technologies to implement serialization and deserialization, or call corresponding serialization library functions, depending on the actual needs and the characteristics of the programming language used.
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