java序列化和反序列化

什么是java序列化和反序列化？

　　序列化的原理是将一个对象转成字节流，使其能被写入到文件中，通过网络传输或者存储在数据库中。反序列化则与其相反。
简而言之，序列化就是将对象转成字节流，反序列化则是将字节流重新恢复成对象。
　　一个类只有实现了java.io.Serializable接口才有资格进行序列化。

定义Person类：

该类中将nationality声明为transient，所以该参数不会参与序列化操作。

package com.led.javabase;

import java.io.Serializable;

/**
 * person entity
 */
public class Person implements Serializable{
    private String name;
    private int age;
    private String gender;
    private transient String nationality;//this field will not take part in serialization

    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;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getNationality() {
        return nationality;
    }

    public void setNationality(String nationality) {
        this.nationality = nationality;
    }

    public Person(String name, int age, String gender, String nationality) {
        this.name = name;
        this.age = age;
        this.gender = gender;
        this.nationality = nationality;
    }
}

序列化实例：

下面的例子是将一个person实例序列化到Person.ser文件中，通过FileOutputStream和ObjectOutputStream来进行操作的：

package com.led.javabase;

import java.io.*;

/**
 * java serialization test
 * @author Alan
 */
public class SerializationTest1 {
    public static void main(String[] args) {
        Person person = new Person("Jack",11,"male","US");
        try {
            FileOutputStream fos = new FileOutputStream("Person.ser");
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            oos.writeObject(person);
            oos.close();
            fos.close();
            System.out.println("Serialization done!");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e2) {
            e2.printStackTrace();
        }

    }
}

控制台输出：

反序列化实例：

下面的例子通过使用FileInputStream和ObjectInputStream来进行反序列化，通过读取Person.ser文件，将字节流转成Person类的对象，

由于Person类的nationality参数声明为了transient，所以该参数不参与序列化化操作，导致反序列化该参数输出为null。

package com.led;

import com.led.javabase.Person;

import java.io.*;

/**
 * @author Alan
 * @Description: De-serialization Object
 * @date 2018/4/22 12:36
 */
public class DeSerializtion {
    public static void main(String[] args) {
        Person o = null;
        try {
            FileInputStream fos = new FileInputStream("Person.ser");
            ObjectInputStream ois = new ObjectInputStream(fos);
            o = (Person) ois.readObject();
            ois.close();
            fos.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return;
        } catch (IOException e2){
            e2.printStackTrace();
            return;
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
            return;
        }
        System.out.println("student's name: " + o.getName());
        System.out.println("student's age: " + o.getAge());
        System.out.println("student's gender: " + o.getGender());
        System.out.println("student's nationality: " + o.getNationality());

    }
}

 

控制台输出：