Javaオブジェクトの圧縮、解凍

import java.io.FileOutputStream;
import java.io.File;
import java.io.ObjectOutputStream;
import java.io.IOException;
import java.util.zip.GZIPOutputStream;

public class ZipObject {
    public static void main(String[] args) {
    	User Jlee = new User();
    	Jlee.setId(new Long(1));
    	Jlee.setUsername("JLee");
    	Jlee.setPassword("111");

        User user = new User();
        user.setId(new Long(2));
        user.setUsername(" ");
        user.setPassword("123");

        System.out.println(" ...");
        
        try {
            FileOutputStream fos = new FileOutputStream(new File("user.dat"));
            GZIPOutputStream gos = new GZIPOutputStream(fos);
            ObjectOutputStream oos = new ObjectOutputStream(gos);

            // Java 
            oos.writeInt(2) ;
            // Java 
            oos.writeObject(Jlee);
            oos.writeObject(user);

            oos.flush();
            oos.close();

            gos.close();
            fos.close();
            
            System.out.println(" ");
        } catch (IOException e) {
        	System.out.println(" ");
            e.printStackTrace();
        }
    }
}

import java.io.FileInputStream;
import java.io.File;
import java.io.ObjectInputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;


public class UnzipObject {
    public static void main(String[] args) {

        try {
            FileInputStream fis = new FileInputStream(new File("user.dat"));
            GZIPInputStream gis = new GZIPInputStream(fis);
            ObjectInputStream ois = new ObjectInputStream(gis);

            System.out.println(" ...");
            
            // Java 
            int count = ois.readInt() ;
            for(int i=0;i<count;i++){
            	// 
            	User Jlee = (User) ois.readObject();
            	System.out.println(Jlee);
            }

            ois.close();
            gis.close();
            fis.close();
            
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

    }
}

import java.io.Serializable;

public class User implements Serializable {        

	private static final long serialVersionUID = 5968179219405462308L;
	
	private Long id;
    private String username;
    private String password;

    public User() {
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("id=").append(id);
        sb.append("; username=").append(username);
        sb.append("; password=").append(password);
        return sb.toString();
    }
}