Java中对象的序列化和反序列化

1)对象序列化，就是将Object转换成byte序列，反之叫对象的反序列化 
2)序列化流(ObjectOutputStream),是过滤流----writeObject

   反序列化流(ObjectInputStream)---readObject

3)序列化接口(Serializable)
   对象必须实现序列化接口 ，才能进行序列化，否则将出现异常
   这个接口，没有任何方法，只是一个标准
4) transient关键字
    //自己完成序列化操作
    private void writeObject(java.io.ObjectOutputStream s)
       throws java.io.IOException
    //自己完成反序列化操作
    private void readObject(java.io.ObjectInputStream s)
       throws java.io.IOException, ClassNotFoundException

例子：

package com.imooc.io;import java.io.Serializable;public class Student implements Serializable{private String stuno;private String stuname;//该元素不会进行jvm默认的序列化,但可以通过writeObject，readObject自己完成这个元素的序列化private transient int stuage;  public Student(String stuno, String stuname, int stuage) {super();this.stuno = stuno;this.stuname = stuname;this.stuage = stuage;}@Overridepublic String toString() {return "Student [stuno=" + stuno + ", stuname=" + stuname + ", stuage="+ stuage + "]";} private void writeObject(java.io.ObjectOutputStream s)        throws java.io.IOException{ s.defaultWriteObject();//把jvm能默认序列化的元素进行序列化操作 s.writeInt(stuage);//自己完成stuage的序列化 } private void readObject(java.io.ObjectInputStream s)        throws java.io.IOException, ClassNotFoundException{  s.defaultReadObject();//把jvm能默认反序列化的元素进行反序列化操作  this.stuage = s.readInt();//自己完成stuage的反序列化操作}}

public static void main(String[] args) throws Exception{String file = "demo/obj.dat";//1.对象的序列化/*ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(file));Student stu = new Student("10001", "张三", 20);oos.writeObject(stu);oos.flush();oos.close();*/ObjectInputStream ois = new ObjectInputStream(new FileInputStream(file));Student stu = (Student)ois.readObject();System.out.println(stu);ois.close();}

5)序列化中 子类和父类构造函数的调用问题

对子类对象进行反序列化操作时，如果其父类没有实现序列化接口那么其父类的构造函数会被调用

例子：

public class Demo{public static void main(String[] args) throws Exception{/*ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("demo/obj1.dat"));Foo2 foo2 = new Foo2();oos.writeObject(foo2);oos.flush();oos.close();*///反序列化是否递归调用父类的构造函数/*ObjectInputStream ois = new ObjectInputStream(new FileInputStream("demo/obj1.dat"));Foo2 foo2 = (Foo2)ois.readObject();System.out.println(foo2);ois.close();*//*ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("demo/obj1.dat"));Bar2 bar2 = new Bar2();oos.writeObject(bar2);oos.flush();oos.close();*/ObjectInputStream ois = new ObjectInputStream(new FileInputStream("demo/obj1.dat"));Bar2 bar2 = (Bar2)ois.readObject();System.out.println(bar2);ois.close();}}/* *   一个类实现了序列化接口，那么其子类都可以进行序列化 */class Foo implements Serializable{public Foo(){System.out.println("foo...");}}class Foo1 extends Foo{public Foo1(){System.out.println("foo1...");}}class Foo2 extends Foo1{public Foo2(){System.out.println("foo2...");}}class Bar{public Bar(){System.out.println("bar");}}class Bar1 extends Bar{public Bar1(){System.out.println("bar1..");}}class Bar2 extends Bar1 implements Serializable{public Bar2(){System.out.println("bar2...");}}