Utility methods for file and stream copying
/*
* 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();
}
}
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