• ObjectInputStream (byte stream) and ObjectOutputStream (byte stream)
• In addition to saving the basic data type, there are also custom objects, which are read by Object and need to be coerced to use.
• Serialization: Output stream,
• Deserialization: Input stream
• Consistent with data flow, it must be written before read, read and write in the same order.
• Serialized objects must implement the java.io.Serializable interface

• Transit: This data does not need serialization, data transparency (output shows null),private transient String name;

  // Read after writing. The number of read is consistent with that of write.

  public class n {
  
  public static void main(String[]args) throws IOException, ClassNotFoundException
  {

  Write byte array
  // Write out serialization
  ByteArrayOutputStream os=new ByteArrayOutputStream();
  ObjectOutputStream oos=new ObjectOutputStream(new BufferedOutputStream(os));
  ha ff=new ha("hh",222);

  oos.writeUTF("Ha-ha");
  oos.writeChar('q');
  oos.writeBoolean(false);
  
  oos.writeObject(ff);
  oos.flush();
  byte[] datas=os.toByteArray();
  oos.close();
  //Read deserialization
  ObjectInputStream ois =new ObjectInputStream(new BufferedInputStream(new ByteArrayInputStream(datas)));
  String s=ois.readUTF();
  char ch=ois.readChar();
  boolean flag=ois.readBoolean(); 
  Object str=ois.readObject();  //Object requires mandatory transformation
  
  //Restore (determine which class it is, and then force conversion):
  if (str instanceof String ) //String classes are converted directly into strings
  {
      String s1=(String)str;
      System.out.println(s1);
  }
  if(str instanceof Data)
  {
      Date d=(Date)str;
      System.out.println(d);
  }
  if(str instanceof ha)
  {
      ha fr=(ha)str;
      System.out.println(fr.getName()+fr.getSalary());
  }
  ois.close();
  }
  
  //javabean for encapsulating data   
  class ha implements java.io.Serializable  {
  
  private transient String name;  //This data does not need serialization and is transparent.
  private double salary;
  
  public ha()
      {
  
  }
  
  public ha(String name,double salary)
  {
  this.name=name;
  this.salary=salary;
  }
  
  public String getName() {
  return name;
  }
  
  public void setName(String name) {
  this.name = name;
  }
  
  public double getSalary() {
  return salary;
  }
  
  public void setSalary(double salary) {
  this.salary = salary;
  }
  
  }

Write to the file:

      ObjectOutputStream oos=new ObjectOutputStream(new  BufferedOutputStream(new FileOutputStream("D:/d/s")));
        ha ff=new ha("hh",222);
        oos.writeUTF("what");
        oos.writeObject(ff);
        oos.flush();
        oos.close();

    //When used, deserialize objects

    ObjectInputStream  ois=new ObjectInputStream(new BufferedInputStream(new FileInputStream("D:/d/s")));
    String s=ois.readUTF();
    Object it=ois.readObject();

    if(it instanceof ha)
    {
        ha q=(ha)it;
        System.out.println(q.getName()+q.getSalary());
    }
    ois.close();

    //javabean for encapsulating data
class ha implements java.io.Serializable  {

private transient String name;  //This data does not need serialization and is transparent.
private double salary;

public ha()
{

}

public ha(String name,double salary)
{
    this.name=name;
    this.salary=salary;
}

public String getName() {
    return name;
}

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

public double getSalary() {
    return salary;
}

public void setSalary(double salary) {
    this.salary = salary;
}

}