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。

 1 package com.led.javabase;
 2 
 3 import java.io.Serializable;
 4 
 5 /**
 6  * person entity
 7  */
 8 public class Person implements Serializable{
 9     private String name;
10     private int age;
11     private String gender;
12     private transient String nationality;//this field will not take part in serialization
13 
14     public String getName() {
15         return name;
16     }
17 
18     public void setName(String name) {
19         this.name = name;
20     }
21 
22     public int getAge() {
23         return age;
24     }
25 
26     public void setAge(int age) {
27         this.age = age;
28     }
29 
30     public String getGender() {
31         return gender;
32     }
33 
34     public void setGender(String gender) {
35         this.gender = gender;
36     }
37 
38     public String getNationality() {
39         return nationality;
40     }
41 
42     public void setNationality(String nationality) {
43         this.nationality = nationality;
44     }
45 
46     public Person(String name, int age, String gender, String nationality) {
47         this.name = name;
48         this.age = age;
49         this.gender = gender;
50         this.nationality = nationality;
51     }
52 }

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：

 1 package com.led.javabase;
 2 
 3 import java.io.*;
 4 
 5 /**
 6  * java serialization test
 7  * @author Alan
 8  */
 9 public class SerializationTest1 {
10     public static void main(String[] args) {
11         Person person = new Person("Jack",11,"male","US");
12         try {
13             FileOutputStream fos = new FileOutputStream("Person.ser");
14             ObjectOutputStream oos = new ObjectOutputStream(fos);
15             oos.writeObject(person);
16             oos.close();
17             fos.close();
18             System.out.println("Serialization done!");
19         } catch (FileNotFoundException e) {
20             e.printStackTrace();
21         } catch (IOException e2) {
22             e2.printStackTrace();
23         }
24 
25     }
26 }

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。

 1 package com.led;
 2 
 3 import com.led.javabase.Person;
 4 
 5 import java.io.*;
 6 
 7 /**
 8  * @author Alan
 9  * @Description: De-serialization Object
10  * @date 2018/4/22 12:36
11  */
12 public class DeSerializtion {
13     public static void main(String[] args) {
14         Person o = null;
15         try {
16             FileInputStream fos = new FileInputStream("Person.ser");
17             ObjectInputStream ois = new ObjectInputStream(fos);
18             o = (Person) ois.readObject();
19             ois.close();
20             fos.close();
21         } catch (FileNotFoundException e) {
22             e.printStackTrace();
23             return;
24         } catch (IOException e2){
25             e2.printStackTrace();
26             return;
27         } catch (ClassNotFoundException e) {
28             e.printStackTrace();
29             return;
30         }
31         System.out.println("student's name: " + o.getName());
32         System.out.println("student's age: " + o.getAge());
33         System.out.println("student's gender: " + o.getGender());
34         System.out.println("student's nationality: " + o.getNationality());
35 
36     }
37 }

 

控制台输出：