Save objects to a file in Java

Description

The following code shows how to save objects to a file.

Example


//from  w  w w.jav a2  s .  c  o m
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Date;

public class Main {
  public static void main(String[] arguments) {
    Message mess = new Message();
    String author = "London";
    String recipient = "G, B";
    String[] letter = { "Merry Christmas." };
    Date now = new Date();
    mess.writeMessage(author, recipient, now, letter);
    try {
      FileOutputStream fo = new FileOutputStream("Message.obj");
      ObjectOutputStream oo = new ObjectOutputStream(fo);
      oo.writeObject(mess);
      oo.close();
      System.out.println("Object created successfully.");
    } catch (IOException e) {
      System.out.println("Error - " + e.toString());
    }
  }
}

class Message implements Serializable {
  int lineCount;

  String from, to;

  Date when;

  String[] text;

  void writeMessage(String inFrom, String inTo, Date inWhen, String[] inText) {

    text = new String[inText.length];
    for (int i = 0; i < inText.length; i++)
      text[i] = inText[i];
    lineCount = inText.length;
    to = inTo;
    from = inFrom;
    when = inWhen;
  }
}

The code above generates the following result.





















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