filecopyutils.java

Java/J2EE application framework based on [Expert One-on-One J2EE Design and Development] by Rod John

/*
 * Copyright 2002-2004 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */ 

package org.springframework.util;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Simple utility methods for file and stream copying.
 * All copy methods use a block size of 4096 bytes,
 * and close all affected streams when done.
 *
 * <p>Mainly for use within the framework,
 * but also useful for application code.
 *
 * @author Juergen Hoeller
 * @since 06.10.2003
 */
public abstract class FileCopyUtils {

	private static final Log logger = LogFactory.getLog(FileCopyUtils.class);

	public static final int BUFFER_SIZE = 4096;


	//---------------------------------------------------------------------
	// Copy methods for java.io.File
	//---------------------------------------------------------------------

	/**
	 * Copy the contents of the given input File to the given output File.
	 * @param in the file to copy from
	 * @param out the file to copy to
	 * @throws IOException in case of I/O errors
	 */
	public static void copy(File in, File out) throws IOException {
		copy(new BufferedInputStream(new FileInputStream(in)),
		    new BufferedOutputStream(new FileOutputStream(out)));
	}

	/**
	 * Copy the contents of the given byte array to the given output File.
	 * @param in the byte array to copy from
	 * @param out the file to copy to
	 * @throws IOException in case of I/O errors
	 */
	public static void copy(byte[] in, File out) throws IOException {
		ByteArrayInputStream inStream = new ByteArrayInputStream(in);
		OutputStream outStream = new BufferedOutputStream(new FileOutputStream(out));
		copy(inStream, outStream);
	}

	/**
	 * Copy the contents of the given input File into a new byte array.
	 * @param in the file to copy from
	 * @return the new byte array that has been copied to
	 * @throws IOException in case of I/O errors
	 */
	public static byte[] copyToByteArray(File in) throws IOException {
		return copyToByteArray(new BufferedInputStream(new FileInputStream(in)));
	}


	//---------------------------------------------------------------------
	// Copy methods for java.io.InputStream / java.io.OutputStream
	//---------------------------------------------------------------------

	/**
	 * Copy the contents of the given InputStream to the given OutputStream.
	 * Closes both streams when done.
	 * @param in the stream to copy from
	 * @param out the stream to copy to
	 * @throws IOException in case of I/O errors
	 */
	public static void copy(InputStream in, OutputStream out) throws IOException {
		try {
			byte[] buffer = new byte[BUFFER_SIZE];
			int nrOfBytes = -1;
			while ((nrOfBytes = in.read(buffer)) != -1) {
				out.write(buffer, 0, nrOfBytes);
			}
			out.flush();
		}
		finally {
			try {
				in.close();
			}
			catch (IOException ex) {
				logger.warn("Could not close InputStream", ex);
			}
			try {
				out.close();
			}
			catch (IOException ex) {
				logger.warn("Could not close OutputStream", ex);
			}
		}
	}

	/**
	 * Copy the contents of the given byte array to the given OutputStream.
	 * Closes the stream when done.
	 * @param in the byte array to copy from
	 * @param out the OutputStream to copy to
	 * @throws IOException in case of I/O errors
	 */
	public static void copy(byte[] in, OutputStream out) throws IOException {
		try {
			out.write(in);
		}
		finally {
			try {
				out.close();
			}
			catch (IOException ex) {
				logger.warn("Could not close OutputStream", ex);
			}
		}
	}

	/**
	 * Copy the contents of the given InputStream into a new byte array.
	 * Closes the stream when done.
	 * @param in the stream to copy from
	 * @return the new byte array that has been copied to
	 * @throws IOException in case of I/O errors
	 */
	public static byte[] copyToByteArray(InputStream in) throws IOException {
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		copy(in, out);
		return out.toByteArray();
	}


	//---------------------------------------------------------------------
	// Copy methods for java.io.Reader / java.io.Writer
	//---------------------------------------------------------------------

	/**
	 * Copy the contents of the given Reader to the given Writer.
	 * Closes both when done.
	 * @param in the Reader to copy from
	 * @param out the Writer to copy to
	 * @throws IOException in case of I/O errors
	 */
	public static void copy(Reader in, Writer out) throws IOException {
		try {
			char[] buffer = new char[BUFFER_SIZE];
			int nrOfBytes = -1;
			while ((nrOfBytes = in.read(buffer)) != -1) {
				out.write(buffer, 0, nrOfBytes);
			}
			out.flush();
		}
		finally {
			try {
				in.close();
			}
			catch (IOException ex) {
				logger.warn("Could not close Reader", ex);
			}
			try {
				out.close();
			}
			catch (IOException ex) {
				logger.warn("Could not close Writer", ex);
			}
		}
	}

	/**
	 * Copy the contents of the given String to the given output Writer.
	 * Closes the write when done.
	 * @param in the String to copy from
	 * @param out the Writer to copy to
	 * @throws IOException in case of I/O errors
	 */
	public static void copy(String in, Writer out) throws IOException {
		try {
			out.write(in);
		}
		finally {
			try {
				out.close();
			}
			catch (IOException ex) {
				logger.warn("Could not close Writer", ex);
			}
		}
	}

	/**
	 * Copy the contents of the given Reader into a String.
	 * Closes the reader when done.
	 * @param in the reader to copy from
	 * @return the String that has been copied to
	 * @throws IOException in case of I/O errors
	 */
	public static String copyToString(Reader in) throws IOException {
		StringWriter out = new StringWriter();
		copy(in, out);
		return out.toString();
	}

}