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Storing classes in files

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Join Date: Apr 2008

Posts: 160

Reputation: dmanw100 is on a distinguished road

Solved Threads: 12

dmanw100

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Junior Poster

Storing classes in files

May 23rd, 2009

Hello,
I am trying to do something very simple but my dial up connection is making it hard to research so I'd like some help! I'm trying to store instances of classes I created in a file. Something along these lines:

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
class apple
{
	int flavor;
	String color;
	apple(int a, String b)
	{
		flavor = a;
		color = b;
	}
}
 
//.....
 
	apple RedDelicious = new apple(10, "red");
	writeFile.write(RedDelicious);
class apple
{
	int flavor;
	String color;
	apple(int a, String b)
	{
		flavor = a;
		color = b;
	}
}

//.....

	apple RedDelicious = new apple(10, "red");
	writeFile.write(RedDelicious);

I know that there is some way to do this through serialization and I've also heard that something along the lines of FileOutputStream/FileInputStream will allow me to write/read the classes but I would appreciate a little guidance on their use in this context. I'm sorry to bother you guys but my dial up is hindering the research process! Thanks!

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Join Date: Oct 2008

Posts: 2,612

Reputation: adatapost has much to be proud of

Solved Threads: 463

adatapost

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Posting Maven

Re: Storing classes in files

May 24th, 2009

Your class must implements a java.io.Serializable Interface and one more thing is that you have to use java.io.ObjectInputStream and java.io.ObjectOutputStream class to read and write objects respectively.

 Help with Code Tags 
 Java Syntax (Toggle Plain Text) 
class apple implements java.io.Serializable
{
	int flavor;
	String color;
	apple(int a, String b)
	{
		flavor = a;
		color = b;
	}
}
 
//.....
 
	apple RedDelicious = new apple(10, "red");
                java.io.ObjectOutputStream os=new java.io.ObjectOutputStream(new java.io.FileOutputStream("data.txt"));
 
	os.writeObject(RedDelicious);
                os.flush();
class apple implements java.io.Serializable
{
	int flavor;
	String color;
	apple(int a, String b)
	{
		flavor = a;
		color = b;
	}
}

//.....
               
	apple RedDelicious = new apple(10, "red");
                java.io.ObjectOutputStream os=new java.io.ObjectOutputStream(new java.io.FileOutputStream("data.txt"));

	os.writeObject(RedDelicious);
                os.flush();