Java Serialization of Java Objects and Primitives

一、Introduction

　　1. What is Java Serialization?

　　　　Java Serialization is the process of converting the state information of Java^TM objects into a form(byte stream) that can be stored or transmitted.

　　　　Java Serialization is used to store and retrieve Java^TM objects, which is essential to building the most applications.

　　2. Why we need Java Serialization?

　　　　objects persistence、transmission and extensible mechanism　　

二、Simples

public class SerializationTest {

  public static void main(String[] args) {
    try {
      // FileOutputSteam is used to receive bytes
      FileOutputStream fos = new FileOutputStream("tmp");
      // ObjectOutput serializes Array, enum constants, Class Object, String
      ObjectOutput objectOutput = new ObjectOutputStream(fos);
      // DataOutputStream serializes primitive data, such as int, char, byte, boolean
      DataOutputStream dos = new DataOutputStream(fos);

      objectOutput.writeObject("hello serialization");
      objectOutput.flush();

      dos.writeBoolean(true);
      dos.flush();

      // Reading an object from a stream
      FileInputStream fis = new FileInputStream("tmp");
      ObjectInputStream ois = new ObjectInputStream(fis);
      DataInputStream dis = new DataInputStream(fis);

      String s = (String)ois.readObject();
      boolean b = dis.readBoolean();

      System.out.println(s); // hello serialization
      System.out.println(b); // true
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}