What is serialization in java

#Serialization: refers to the Java object data in the heap memory, which is stored in a disk file in some way, or passed to other network nodes (network transmission). This process is called serialization, which usually refers to the process of converting a data structure or object into binary.                                                                                                       (Recommended learning: java course )

Convert the object into binary for storage or network transmission.

The role of serialization

① When you want to save objects in memory to a file or database;

② When you want to use sockets When transmitting objects over the network;

③ When you want to transmit objects through RMI

Some application scenarios involve converting objects into binary, and serialization ensures that they can be read successfully Saved object.

Java serialization implementation

To achieve object serialization, the most direct operation is to implement the Serializable interface

Use objects in the IO stream Streams can implement serialization operations, save objects to files, and then read them out.

First create an object and implement the Serializable interface:

import java.io.Serializable;

public class User implements Serializable{
    private static final long serialVersionUID = 1L;
    private String name;
    private int age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "User [name=" + name + ", age=" + age + "]";
    }
}

Use the object stream to write a tool class for saving and reading objects:

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

public class SerializeUtil {
    // 保存对象，序列化
    public static void saveObject(Object object) throws Exception {
        ObjectOutputStream out = null;
        FileOutputStream fout = null;
        try {
            fout = new FileOutputStream("D:/1.txt");
            out = new ObjectOutputStream(fout);
            out.writeObject(object);
        } finally {
            fout.close();
            out.close();
        }
    }
    // 读取对象，反序列化
    public static Object readObject() throws Exception {
        ObjectInputStream in = null;
        FileInputStream fin = null;
        try {
            fin = new FileInputStream("D:/1.txt");
            in = new ObjectInputStream(fin);
            Object object = in.readObject();
            return object;
        } finally {
            fin.close();
            in.close();
        }
    }
}

Test:

public class Main {
    public static void main(String[] args) {
        User user = new User();
        user.setName("旭旭宝宝");
        user.setAge(33);
        // 保存
        try {
            SerializeUtil.saveObject(user);
        } catch (Exception e) {
            System.out.println("保存时异常：" + e.getMessage());
        }
        // 读取
        User userObject;
        try {
            userObject = (User) SerializeUtil.readObject();
            System.out.println(userObject);
        } catch (Exception e) {
            System.out.println("读取时异常：" + e.getMessage());
        }
    }
}

Test result:

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