Can we write a Hashtable to a file?

Question

I have a Hashtable<string,string>, in my program I want to record the values of the Hashtable to process later.

My question is: can we write object Hastable to a file? If so, how can we later load that file?

Answer 1

Yes, using binary serialization (ObjectOutputStream):

FileOutputStream fos = new FileOutputStream("t.tmp");
ObjectOutputStream oos = new ObjectOutputStream(fos);

oos.writeObject(yourHashTable);
oos.close();

Then you can read it using ObjectInputStream

The objects that you put inside the Hashtable (or better - HashMap) have to implement Serializable

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If you want to store the Hashtable in a human-readable format, you can use java.beans.XMLEncoder:

FileOutputStream fos = new FileOutputStream("tmp.xml");
XMLEncoder e = new XMLEncoder(fos);
e.writeObject(yourHashTable);
e.close();