— Scott McNealy, Sun Microsystems Chairman, President and ceo

serialization 
and
file I/O
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Writing a String to a Text File
Saving objects, through serialization, is the easiest way to save and 
restore data between runnings of a Java program. But sometimes you 
need to save data to a plain old text fi le. Imagine your Java program 
has to write data to a simple text fi le that some other (perhaps non-
Java) program needs to read. You might, for example, have a servlet 
(Java code running within your web server) that takes form data the 
user typed into a browser, and writes it to a text fi le that somebody else 
loads into a spreadsheet for analysis. 
Writing text data (a String, actually) is similar to writing an object, 
except you write a String instead of an object, and you use a 
FileWriter instead of a FileOutputStream (and you don’t chain it to an 
ObjectOutputStream).
50,Elf,bow, sword,dust
200,Troll,bare hands,big ax
120,Magician,spells,invisibility
What the game character data 
might look like if you wrote it 
out as a human-readable text file.
To write a serialized object:
objectOutputStream.writeObject(someObject);
To write a String:
fi leWriter.write(“My fi rst String to save”);
import java.io.*;
class WriteAFile {
public static void main (String[] args) {
try {
FileWriter writer = new FileWriter(“Foo.txt”);
writer.write(“hello foo!”);
writer.close();
} catch(IOException ex) {
ex.printStackTrace();
}
} 
}
We need the java.io package for FileWriter 
ALL the I/O stuff 
must be in a try/catch. 
Everything can throw an 
IOException!!
If the file “Foo.txt” does not 
exist, FileWriter will create it.
The write() method takes 
a String
Close it when you’re done!

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