java对象序列化

对象序列化是指将java对象转化成二进制流的过程。反之则是反序列化的过程。java中对象通过实现Serializable借口来实现序列化。序列化需要注意以下几点：

1.静态属性无法进行序列化（静态属性是属于类而非对象）。

2.如果A对象属性包含B对象的引用，则序列化A对象时B对象也会被序列化。

3.若被序列化的对象中包含非序列化的属性，序列化是会报 java.io.NotSerializableException 错误，未被序列化的类要加关键字 transient 修饰。

package com.example.demo;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.Serializable;

public class TestSerilizable{

   public static void main(String[] args) throws IOException {
       OutputStream fos = new FileOutputStream("D:\\a.txt");
       ObjectOutputStream oos = new ObjectOutputStream(fos);
       Person p = new Person();
       Cat cat = new Cat("katty",p);
       oos.writeObject(cat);
       oos.close();
   }
   
}
class Person{
   
   private String name;

   public Person() {
       // TODO Auto-generated constructor stub
   }
   
   public Person(String name) {
       this.name=name;
   }
   
   public String getName() {
       return name;
   }

   public void setName(String name) {
       this.name = name;
   }
   
}

class Cat implements Serializable{
   /**
    * 
    */
   private static final long serialVersionUID = 1L;

   private String name;

   private  Person p;
   
   public Cat() {
       // TODO Auto-generated constructor stub
   }
   
   public Cat(String name,Person p) {
       this.name=name;
       this.p=p;
   }

   public String getName() {
       return name;
   }

   public void setName(String name) {
       this.name = name;
   }

   public Person getP() {
       return p;
   }

   public void setP(Person p) {
       this.p = p;
   }
   
   
}

控制台报如下错误：

 Exception in thread "main" java.io.NotSerializableException: com.example.demo.Person
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1184)
    at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548)
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509)
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)
    at com.example.demo.TestSerilizable.main(TestSerilizable.java:16)

p属性加上 transient 修饰：

class Cat implements Serializable{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    private String name;

    private transient Person p;
    
    public Cat() {
        // TODO Auto-generated constructor stub
    }
    
    public Cat(String name,Person p) {
        this.name=name;
        this.p=p;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Person getP() {
        return p;
    }

    public void setP(Person p) {
        this.p = p;
    }
    
    
}

程序正常运行。所以序列化的时候一定要注意哦。