File reading/writing/parsing utilities.

FileUtils.java

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * Utilities for working with files.
 * 
 * @author Thomas Owens
 */
public class FileUtils {
  /**
	 * Get a byte array that contains the file. Due to the limitations on the
	 * maximum size of an array, if the file is greater than 2147483647 bytes,
	 * or 2.147GB.
	 * 
	 * @param file
	 *            the file to convert into a byte[]
	 * @return the bytes of the file
	 * @throws IllegalArgumentException
	 *             the argument is null, the file does not exist, or the file is
	 *             too large to be read into a byte array (> 2147483647 bytes)
	 * @throws IOException
	 *             the file could not be read
	 */
	public static byte[] getFileBytes(File file) throws IOException {
		if (file == null || !file.exists()) {
			throw new IllegalArgumentException("Specified file must exist.");
		}

		long fileLength = file.length();

		// Arrays can not be larger than Integer.MAX_VALUE.
		if (fileLength > Integer.MAX_VALUE) {
			throw new IllegalArgumentException(
					"File is too large to read into a byte array");
		}

		InputStream is = new FileInputStream(file);
		byte[] fileBytes = new byte[(int) fileLength];

		int offset = 0;
		int bytesRead = 0;

		while (offset < fileBytes.length
				&& (bytesRead = is.read(fileBytes, offset, fileBytes.length
						- offset)) > 0) {
			offset += bytesRead;
		}

		if (offset < fileBytes.length) {
			is.close();
			throw new IOException("File not completely read");
		}
		
		is.close();

		return fileBytes;
	}
}