Computer Science 202
Introduction to Programming
Fall 2012, The College of Saint Rose
HelloWorldFile BlueJ Project
Click here to download a BlueJ project for HelloWorldFile.
HelloWorldFile Source Code
The Java source code for HelloWorldFile is below. Click on a file name to download it.
/*
* Example HelloWorldFile: print a "Hello, World" message to a
* file.
*
* Jim Teresco, The College of Saint Rose, CSC 202, Fall 2012
*
* $Id: HelloWorldFile.java 1962 2012-10-29 22:11:21Z terescoj $
*/
// we need to use a few more items from the Java API when writing files
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
public class HelloWorldFile {
// we need to change up our main method signature just a bit --
// it is possible that an error condition could occur if we try
// to create a file and cannot do so. There are a number of
// mechanisms we can use to handle this in Java -- the simplest
// and the one we'll use for now is to add this extra clause
// to the end of our main method signature to say that it's OK
// for that error to occur and essentially that our program can
// just crash if that happens.
public static void main(String[] args) throws IOException {
// We create a PrintWriter on a File to be able to
// write text to that file. "hello.out" here is the name
// of the file we wish to create. It will be created in
// the same folder where our BlueJ project resides.
// Beware: if the file previously existed, it will be
// overwritten without warning!
PrintWriter output = new PrintWriter(new File("hello.out"));
// "output" can now be used like "System.out", except that
// the things we print end up in the file instead of in
// our terminal window.
output.println("Hello, File Output World!");
// when we finish with a file, we need to "close" it. This tells
// the operating system that it should make sure everything
// we put into the file has been written to the disk.
output.close();
}
}