Java中serializable序列化

1. 序列化

transient不会被序列化。
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
public class SerializableTest1{
    public static void main(String[] args) throws Exception{
        Person p1 = new Person(20, "zhangsan", 4.55);
        Person p2 = new Person(50, "lisi", 4.67);
        Person p3 = new Person(10, "wangwu", 17.78);
        FileOutputStream fos = new FileOutputStream("person.txt");
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        oos.writeObject(p1);
        oos.writeObject(p2);
        oos.writeObject(p3);
        oos.close();
        System.out.println("--------------------");
        FileInputStream fis = new FileInputStream("person.txt");
        ObjectInputStream ois = new ObjectInputStream(fis);

        Person p = null;
        for (int i = 0; i < 3; i++){
            p = (Person) ois.readObject();
            System.out.println(p.age + "," + p.name + "," + p.height);
        }
        ois.close();
    }
}
class Person implements Serializable{
    int age;
    String name;
    double height;
    public Person(int age, String name, double height){
        this.age = age;
        this.name = name;
        this.height = height;
    }
}

2. 反序列化

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
public class SerializableTest2 {
    public static void main(String[] args) throws Exception {
        Person2 p1 = new Person2(20, "zhangsan", 4.55);
        Person2 p2 = new Person2(50, "lisi", 4.67);
        Person2 p3 = new Person2(10, "wangwu", 17.78);
        FileOutputStream fos = new FileOutputStream("Person2.txt");
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        oos.writeObject(p1);
        oos.writeObject(p2);
        oos.writeObject(p3);
        oos.close();
        System.out.println("--------------------");
        FileInputStream fis = new FileInputStream("Person2.txt");
        ObjectInputStream ois = new ObjectInputStream(fis);
        Person2 p = null;
        for (int i = 0; i < 3; i++){
            p = (Person2) ois.readObject();
            System.out.println(p.age + "," + p.name + "," + p.height);
        }
        ois.close();
    }
}
class Person2 implements Serializable{
    int age;
    String name;
    double height;
    public Person2(int age, String name, double height){
        this.age = age;
        this.name = name;
        this.height = height;
    }
    private void writeObject(java.io.ObjectOutputStream out) throws IOException{
        out.writeInt(age);
        out.writeUTF(name);
        System.out.println("write object");
    }
    private void readObject(java.io.ObjectInputStream in) throws IOException,ClassNotFoundException{
        age = in.readInt();
        name = in.readUTF();
        System.out.println("read object");
    }
}

3. 方法总结

当我们在一个待序列化/反序列化的类中实现了以上两个private方法（方法声明要与上面的保持完全的一致），那么就允许我们以更加底层、更加细粒度的方式控制序列化/反序列化的过程。
private void writeObject(java.io.ObjectOutputStream out) throws IOException{
    out.writeInt(age);
    out.writeUTF(name);
    System.out.println("write object");
}
private void readObject(java.io.ObjectInputStream in) throws IOException,ClassNotFoundException{
    age = in.readInt();
    name = in.readUTF();
    System.out.println("read object");
}