FileCopyUtils.java Source code

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Here is the source code for FileCopyUtils.java

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/*
 * Copyright 2002-2005 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.
 */

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;

/**
 * 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 {

    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
     * @return the number of bytes copied
     * @throws IOException in case of I/O errors
     */
    public static int copy(File in, File out) throws IOException {

        return 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
     * @return the number of bytes copied
     * @throws IOException in case of I/O errors
     */
    public static int copy(InputStream in, OutputStream out) throws IOException {

        try {
            int byteCount = 0;
            byte[] buffer = new byte[BUFFER_SIZE];
            int bytesRead = -1;
            while ((bytesRead = in.read(buffer)) != -1) {
                out.write(buffer, 0, bytesRead);
                byteCount += bytesRead;
            }
            out.flush();
            return byteCount;
        } finally {
            try {
                in.close();
                out.close();
            } catch (IOException ex) {
                System.out.println("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) {
                System.out.println("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(BUFFER_SIZE);
        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
     * @return the number of characters copied
     * @throws IOException in case of I/O errors
     */
    public static int copy(Reader in, Writer out) throws IOException {

        try {
            int byteCount = 0;
            char[] buffer = new char[BUFFER_SIZE];
            int bytesRead = -1;
            while ((bytesRead = in.read(buffer)) != -1) {
                out.write(buffer, 0, bytesRead);
                byteCount += bytesRead;
            }
            out.flush();
            return byteCount;
        } finally {
            try {
                in.close();
            } catch (IOException ex) {
                System.out.println("Could not close Reader" + ex);
            }
            try {
                out.close();
            } catch (IOException ex) {
                System.out.println("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) {
                System.out.println("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();
    }

}