Java 7 for Absolute Beginners

CHAPTER 8 ■ WRITING AND READING FILES

between the original and the reversed content. Listing 8-17 shows the code with the additional and

changed lines highlighted.

Listing 8-17. Appending rather than replacing

package com.apress.java7forabsolutebeginners.examples;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

public class WriteFile {

public static void main(String[] args) {

// Specify the file

String fileName = "C:" + File.separator + "test"

+ File.separator + "Hamlet.txt";

File hamletFile = new File(fileName);

// Set up a byte array to hold the file's content

byte[] content = new byte[0];

try {

// Create an input stream for the file

FileInputStream hamletInputStream = new FileInputStream(hamletFile);

// Figure out how much content the file has

int bytesAvailable = hamletInputStream.available();

// Set the content array to the length of the content

content = new byte[bytesAvailable];

// Load the file's content into our byte array

hamletInputStream.read(content);

// Close the stream

hamletInputStream.close();

} catch (FileNotFoundException fnfe) {

System.out.println("Couldn't find a file called " + fileName);

} catch (IOException ioe) {

System.out.println("Couldn't read from a file called " + fileName);

}

// Reverse the contents of our array, just so we'll

// know we did something to the file's content

reverseByteArray(content);

try {

// Create a stream for our output

FileOutputStream hamletOutputStream

= new FileOutputStream(hamletFile, true);

// Write a newline character to separate the

// original content from the new content.

hamletOutputStream.write('\n');

// Write our output to the file output stream

// (and thus to our file)

hamletOutputStream.write(content);