333 lines
13 KiB
Java
333 lines
13 KiB
Java
/*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership.
|
|
* The ASF licenses this file to You 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.apache.commons.io;
|
|
|
|
import java.io.ByteArrayInputStream;
|
|
import java.io.IOException;
|
|
import java.io.InputStream;
|
|
import java.io.InputStreamReader;
|
|
import java.io.OutputStream;
|
|
import java.io.OutputStreamWriter;
|
|
import java.io.Reader;
|
|
import java.io.StringReader;
|
|
import java.io.Writer;
|
|
|
|
/**
|
|
* This class provides static utility methods for buffered
|
|
* copying between sources (<code>InputStream</code>, <code>Reader</code>,
|
|
* <code>String</code> and <code>byte[]</code>) and destinations
|
|
* (<code>OutputStream</code>, <code>Writer</code>, <code>String</code> and
|
|
* <code>byte[]</code>).
|
|
* <p>
|
|
* Unless otherwise noted, these <code>copy</code> methods do <em>not</em>
|
|
* flush or close the streams. Often doing so would require making non-portable
|
|
* assumptions about the streams' origin and further use. This means that both
|
|
* streams' <code>close()</code> methods must be called after copying. if one
|
|
* omits this step, then the stream resources (sockets, file descriptors) are
|
|
* released when the associated Stream is garbage-collected. It is not a good
|
|
* idea to rely on this mechanism. For a good overview of the distinction
|
|
* between "memory management" and "resource management", see
|
|
* <a href="http://www.unixreview.com/articles/1998/9804/9804ja/ja.htm">this
|
|
* UnixReview article</a>.
|
|
* <p>
|
|
* For byte-to-char methods, a <code>copy</code> variant allows the encoding
|
|
* to be selected (otherwise the platform default is used). We would like to
|
|
* encourage you to always specify the encoding because relying on the platform
|
|
* default can lead to unexpected results.
|
|
* <p
|
|
* We don't provide special variants for the <code>copy</code> methods that
|
|
* let you specify the buffer size because in modern VMs the impact on speed
|
|
* seems to be minimal. We're using a default buffer size of 4 KB.
|
|
* <p>
|
|
* The <code>copy</code> methods use an internal buffer when copying. It is
|
|
* therefore advisable <em>not</em> to deliberately wrap the stream arguments
|
|
* to the <code>copy</code> methods in <code>Buffered*</code> streams. For
|
|
* example, don't do the following:
|
|
* <pre>
|
|
* copy( new BufferedInputStream( in ), new BufferedOutputStream( out ) );
|
|
* </pre>
|
|
* The rationale is as follows:
|
|
* <p>
|
|
* Imagine that an InputStream's read() is a very expensive operation, which
|
|
* would usually suggest wrapping in a BufferedInputStream. The
|
|
* BufferedInputStream works by issuing infrequent
|
|
* {@link java.io.InputStream#read(byte[] b, int off, int len)} requests on the
|
|
* underlying InputStream, to fill an internal buffer, from which further
|
|
* <code>read</code> requests can inexpensively get their data (until the buffer
|
|
* runs out).
|
|
* <p>
|
|
* However, the <code>copy</code> methods do the same thing, keeping an
|
|
* internal buffer, populated by
|
|
* {@link InputStream#read(byte[] b, int off, int len)} requests. Having two
|
|
* buffers (or three if the destination stream is also buffered) is pointless,
|
|
* and the unnecessary buffer management hurts performance slightly (about 3%,
|
|
* according to some simple experiments).
|
|
* <p>
|
|
* Behold, intrepid explorers; a map of this class:
|
|
* <pre>
|
|
* Method Input Output Dependency
|
|
* ------ ----- ------ -------
|
|
* 1 copy InputStream OutputStream (primitive)
|
|
* 2 copy Reader Writer (primitive)
|
|
*
|
|
* 3 copy InputStream Writer 2
|
|
*
|
|
* 4 copy Reader OutputStream 2
|
|
*
|
|
* 5 copy String OutputStream 2
|
|
* 6 copy String Writer (trivial)
|
|
*
|
|
* 7 copy byte[] Writer 3
|
|
* 8 copy byte[] OutputStream (trivial)
|
|
* </pre>
|
|
* <p>
|
|
* Note that only the first two methods shuffle bytes; the rest use these
|
|
* two, or (if possible) copy using native Java copy methods. As there are
|
|
* method variants to specify the encoding, each row may
|
|
* correspond to up to 2 methods.
|
|
* <p>
|
|
* Origin of code: Excalibur.
|
|
*
|
|
* @author Peter Donald
|
|
* @author Jeff Turner
|
|
* @author Matthew Hawthorne
|
|
* @version $Id: CopyUtils.java 437680 2006-08-28 11:57:00Z scolebourne $
|
|
* @deprecated Use IOUtils. Will be removed in 2.0.
|
|
* Methods renamed to IOUtils.write() or IOUtils.copy().
|
|
* Null handling behaviour changed in IOUtils (null data does not
|
|
* throw NullPointerException).
|
|
*/
|
|
public class CopyUtils {
|
|
|
|
/**
|
|
* The default size of the buffer.
|
|
*/
|
|
private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;
|
|
|
|
/**
|
|
* Instances should NOT be constructed in standard programming.
|
|
*/
|
|
public CopyUtils() { }
|
|
|
|
// ----------------------------------------------------------------
|
|
// byte[] -> OutputStream
|
|
// ----------------------------------------------------------------
|
|
|
|
/**
|
|
* Copy bytes from a <code>byte[]</code> to an <code>OutputStream</code>.
|
|
* @param input the byte array to read from
|
|
* @param output the <code>OutputStream</code> to write to
|
|
* @throws IOException In case of an I/O problem
|
|
*/
|
|
public static void copy(byte[] input, OutputStream output)
|
|
throws IOException {
|
|
output.write(input);
|
|
}
|
|
|
|
// ----------------------------------------------------------------
|
|
// byte[] -> Writer
|
|
// ----------------------------------------------------------------
|
|
|
|
/**
|
|
* Copy and convert bytes from a <code>byte[]</code> to chars on a
|
|
* <code>Writer</code>.
|
|
* The platform's default encoding is used for the byte-to-char conversion.
|
|
* @param input the byte array to read from
|
|
* @param output the <code>Writer</code> to write to
|
|
* @throws IOException In case of an I/O problem
|
|
*/
|
|
public static void copy(byte[] input, Writer output)
|
|
throws IOException {
|
|
ByteArrayInputStream in = new ByteArrayInputStream(input);
|
|
copy(in, output);
|
|
}
|
|
|
|
|
|
/**
|
|
* Copy and convert bytes from a <code>byte[]</code> to chars on a
|
|
* <code>Writer</code>, using the specified encoding.
|
|
* @param input the byte array to read from
|
|
* @param output the <code>Writer</code> to write to
|
|
* @param encoding The name of a supported character encoding. See the
|
|
* <a href="http://www.iana.org/assignments/character-sets">IANA
|
|
* Charset Registry</a> for a list of valid encoding types.
|
|
* @throws IOException In case of an I/O problem
|
|
*/
|
|
public static void copy(
|
|
byte[] input,
|
|
Writer output,
|
|
String encoding)
|
|
throws IOException {
|
|
ByteArrayInputStream in = new ByteArrayInputStream(input);
|
|
copy(in, output, encoding);
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------
|
|
// Core copy methods
|
|
// ----------------------------------------------------------------
|
|
|
|
/**
|
|
* Copy bytes from an <code>InputStream</code> to an
|
|
* <code>OutputStream</code>.
|
|
* @param input the <code>InputStream</code> to read from
|
|
* @param output the <code>OutputStream</code> to write to
|
|
* @return the number of bytes copied
|
|
* @throws IOException In case of an I/O problem
|
|
*/
|
|
public static int copy(
|
|
InputStream input,
|
|
OutputStream output)
|
|
throws IOException {
|
|
byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
|
|
int count = 0;
|
|
int n = 0;
|
|
while (-1 != (n = input.read(buffer))) {
|
|
output.write(buffer, 0, n);
|
|
count += n;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
// ----------------------------------------------------------------
|
|
// Reader -> Writer
|
|
// ----------------------------------------------------------------
|
|
|
|
/**
|
|
* Copy chars from a <code>Reader</code> to a <code>Writer</code>.
|
|
* @param input the <code>Reader</code> to read from
|
|
* @param output the <code>Writer</code> to write to
|
|
* @return the number of characters copied
|
|
* @throws IOException In case of an I/O problem
|
|
*/
|
|
public static int copy(
|
|
Reader input,
|
|
Writer output)
|
|
throws IOException {
|
|
char[] buffer = new char[DEFAULT_BUFFER_SIZE];
|
|
int count = 0;
|
|
int n = 0;
|
|
while (-1 != (n = input.read(buffer))) {
|
|
output.write(buffer, 0, n);
|
|
count += n;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
// ----------------------------------------------------------------
|
|
// InputStream -> Writer
|
|
// ----------------------------------------------------------------
|
|
|
|
/**
|
|
* Copy and convert bytes from an <code>InputStream</code> to chars on a
|
|
* <code>Writer</code>.
|
|
* The platform's default encoding is used for the byte-to-char conversion.
|
|
* @param input the <code>InputStream</code> to read from
|
|
* @param output the <code>Writer</code> to write to
|
|
* @throws IOException In case of an I/O problem
|
|
*/
|
|
public static void copy(
|
|
InputStream input,
|
|
Writer output)
|
|
throws IOException {
|
|
InputStreamReader in = new InputStreamReader(input);
|
|
copy(in, output);
|
|
}
|
|
|
|
/**
|
|
* Copy and convert bytes from an <code>InputStream</code> to chars on a
|
|
* <code>Writer</code>, using the specified encoding.
|
|
* @param input the <code>InputStream</code> to read from
|
|
* @param output the <code>Writer</code> to write to
|
|
* @param encoding The name of a supported character encoding. See the
|
|
* <a href="http://www.iana.org/assignments/character-sets">IANA
|
|
* Charset Registry</a> for a list of valid encoding types.
|
|
* @throws IOException In case of an I/O problem
|
|
*/
|
|
public static void copy(
|
|
InputStream input,
|
|
Writer output,
|
|
String encoding)
|
|
throws IOException {
|
|
InputStreamReader in = new InputStreamReader(input, encoding);
|
|
copy(in, output);
|
|
}
|
|
|
|
|
|
// ----------------------------------------------------------------
|
|
// Reader -> OutputStream
|
|
// ----------------------------------------------------------------
|
|
|
|
/**
|
|
* Serialize chars from a <code>Reader</code> to bytes on an
|
|
* <code>OutputStream</code>, and flush the <code>OutputStream</code>.
|
|
* @param input the <code>Reader</code> to read from
|
|
* @param output the <code>OutputStream</code> to write to
|
|
* @throws IOException In case of an I/O problem
|
|
*/
|
|
public static void copy(
|
|
Reader input,
|
|
OutputStream output)
|
|
throws IOException {
|
|
OutputStreamWriter out = new OutputStreamWriter(output);
|
|
copy(input, out);
|
|
// XXX Unless anyone is planning on rewriting OutputStreamWriter, we
|
|
// have to flush here.
|
|
out.flush();
|
|
}
|
|
|
|
// ----------------------------------------------------------------
|
|
// String -> OutputStream
|
|
// ----------------------------------------------------------------
|
|
|
|
/**
|
|
* Serialize chars from a <code>String</code> to bytes on an
|
|
* <code>OutputStream</code>, and
|
|
* flush the <code>OutputStream</code>.
|
|
* @param input the <code>String</code> to read from
|
|
* @param output the <code>OutputStream</code> to write to
|
|
* @throws IOException In case of an I/O problem
|
|
*/
|
|
public static void copy(
|
|
String input,
|
|
OutputStream output)
|
|
throws IOException {
|
|
StringReader in = new StringReader(input);
|
|
OutputStreamWriter out = new OutputStreamWriter(output);
|
|
copy(in, out);
|
|
// XXX Unless anyone is planning on rewriting OutputStreamWriter, we
|
|
// have to flush here.
|
|
out.flush();
|
|
}
|
|
|
|
// ----------------------------------------------------------------
|
|
// String -> Writer
|
|
// ----------------------------------------------------------------
|
|
|
|
/**
|
|
* Copy chars from a <code>String</code> to a <code>Writer</code>.
|
|
* @param input the <code>String</code> to read from
|
|
* @param output the <code>Writer</code> to write to
|
|
* @throws IOException In case of an I/O problem
|
|
*/
|
|
public static void copy(String input, Writer output)
|
|
throws IOException {
|
|
output.write(input);
|
|
}
|
|
|
|
}
|