FileUtil.java

import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import org.apache.log4j.Logger;

public class FileUtil {
	private static final Logger logger = Logger.getLogger(FileUtil.class);

	public static void saveAs(byte[] bytes, String fileLocation) {
		try {
			FileOutputStream fos = new FileOutputStream(new File(fileLocation));
			fos.write(bytes);
			fos.close();
		}
		catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static byte[] download(String fileURL) {
		HttpURLConnection httpConn = null;
		try {
			ByteArrayOutputStream outputStream = null;

			byte[] bytes = null;
			URL url = new URL(fileURL);
			httpConn = (HttpURLConnection) url.openConnection();
			int responseCode = httpConn.getResponseCode();

			if (responseCode == HttpURLConnection.HTTP_OK) {
				String fileName = "";
				String disposition = httpConn.getHeaderField("Content-Disposition");
				String contentType = httpConn.getContentType();
				int contentLength = httpConn.getContentLength();

				if (disposition != null) {
					int index = disposition.indexOf("filename=");
					if (index > 0) {
						fileName = disposition.substring(index + 10, disposition.length() - 1);
					}
				}
				else {
					fileName = fileURL.substring(fileURL.lastIndexOf("/") + 1, fileURL.length());
				}

				logger.error("Content-Type = " + contentType);
				logger.error("Content-Disposition = " + disposition);
				logger.error("Content-Length = " + contentLength);
				logger.error("fileName = " + fileName);

				InputStream inputStream = httpConn.getInputStream();

				outputStream = new ByteArrayOutputStream();

				int bytesRead = -1;
				byte[] buffer = new byte[1024];
				while ((bytesRead = inputStream.read(buffer)) != -1) {
					outputStream.write(buffer, 0, bytesRead);
				}

				outputStream.close();
				inputStream.close();

				logger.error("File downloaded");
				bytes = outputStream.toByteArray();
			}
			else {
				InputStream stream = httpConn.getErrorStream();

				ByteArrayOutputStream buffer = new ByteArrayOutputStream();

				int nRead;
				byte[] data = new byte[1024];

				while ((nRead = stream.read(data, 0, data.length)) != -1) {
					buffer.write(data, 0, nRead);
				}

				buffer.flush();

				String response = new String(buffer.toByteArray());
				logger.error("No file to download. Server replied HTTP code: " + responseCode + "\n" + response);
			}
			return bytes;
		}
		catch (Exception e) {
			e.printStackTrace();
			return null;
		}
		finally {
			if (httpConn != null)
				httpConn.disconnect();
		}
	}

	public static File createTempDirFile(String fileName) {
		return new File(System.getProperty("java.io.tmpdir") + System.getProperty("file.separator") + fileName);
	}

	public static byte[] bytes(String fileName) throws IOException {
		return bytes(new File(fileName));
	}

	public static byte[] bytes(File file) throws IOException {
		int size = (int) file.length();
		byte[] fileContent = new byte[size];
		DataInputStream dis = new DataInputStream(new FileInputStream(file));
		int read = 0;
		int numRead = 0;
		while (read < fileContent.length && (numRead = dis.read(fileContent, read, fileContent.length - read)) >= 0) {
			read = read + numRead;
		}
		dis.close();
		return fileContent;
	}

	public static byte[] bytes(InputStream input) throws IOException {
		ByteArrayOutputStream output = new ByteArrayOutputStream();
		byte[] buffer = new byte[1024 * 4];
		int n = 0;
		while (-1 != (n = input.read(buffer))) {
			output.write(buffer, 0, n);
		}
		return output.toByteArray();
	}
}