com.feilong.lib.net.io.Util Maven / Gradle / Ivy
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/*
* 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 com.feilong.lib.net.io;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
/***
* The Util class cannot be instantiated and stores short static convenience
* methods that are often quite useful.
*
*
* @see CopyStreamException
* @see CopyStreamListener
* @see CopyStreamAdapter
***/
public final class Util{
/**
* The default buffer size ({@value}) used by
* {@link #copyStream copyStream }
* and by the copyReader/copyStream methods if a zero or negative buffer size is supplied.
*/
public static final int DEFAULT_COPY_BUFFER_SIZE = 1024;
// Cannot be instantiated
private Util(){
}
/***
* Copies the contents of an InputStream to an OutputStream using a
* copy buffer of a given size and notifies the provided
* CopyStreamListener of the progress of the copy operation by calling
* its bytesTransferred(long, int) method after each write to the
* destination. If you wish to notify more than one listener you should
* use a CopyStreamAdapter as the listener and register the additional
* listeners with the CopyStreamAdapter.
*
* The contents of the InputStream are
* read until the end of the stream is reached, but neither the
* source nor the destination are closed. You must do this yourself
* outside of the method call. The number of bytes read/written is
* returned.
*
* @param source
* The source InputStream.
* @param dest
* The destination OutputStream.
* @param bufferSize
* The number of bytes to buffer during the copy.
* A zero or negative value means to use {@link #DEFAULT_COPY_BUFFER_SIZE}.
* @param streamSize
* The number of bytes in the stream being copied.
* Should be set to CopyStreamEvent.UNKNOWN_STREAM_SIZE if unknown.
* Not currently used (though it is passed to {@link CopyStreamListener#bytesTransferred(long, int, long)}
* @param listener
* The CopyStreamListener to notify of progress. If
* this parameter is null, notification is not attempted.
* @param flush
* Whether to flush the output stream after every
* write. This is necessary for interactive sessions that rely on
* buffered streams. If you don't flush, the data will stay in
* the stream buffer.
* @return number of bytes read/written
* @throws CopyStreamException
* If an error occurs while reading from the
* source or writing to the destination. The CopyStreamException
* will contain the number of bytes confirmed to have been
* transferred before an
* IOException occurred, and it will also contain the IOException
* that caused the error. These values can be retrieved with
* the CopyStreamException getTotalBytesTransferred() and
* getIOException() methods.
***/
public static long copyStream(
InputStream source,
OutputStream dest,
int bufferSize,
long streamSize,
CopyStreamListener listener,
boolean flush) throws CopyStreamException{
int numBytes;
long total = 0;
byte[] buffer = new byte[bufferSize > 0 ? bufferSize : DEFAULT_COPY_BUFFER_SIZE];
try{
while ((numBytes = source.read(buffer)) != -1){
// Technically, some read(byte[]) methods may return 0 and we cannot
// accept that as an indication of EOF.
if (numBytes == 0){
int singleByte = source.read();
if (singleByte < 0){
break;
}
dest.write(singleByte);
if (flush){
dest.flush();
}
++total;
if (listener != null){
listener.bytesTransferred(total, 1, streamSize);
}
continue;
}
dest.write(buffer, 0, numBytes);
if (flush){
dest.flush();
}
total += numBytes;
if (listener != null){
listener.bytesTransferred(total, numBytes, streamSize);
}
}
}catch (IOException e){
throw new CopyStreamException("IOException caught while copying.", total, e);
}
return total;
}
/**
* Closes the object quietly, catching rather than throwing IOException.
* Intended for use from finally blocks.
*
* @param closeable
* the object to close, may be {@code null}
* @since 3.0
*/
public static void closeQuietly(Closeable closeable){
if (closeable != null){
try{
closeable.close();
}catch (IOException e){
// Ignored
}
}
}
/**
* Closes the socket quietly, catching rather than throwing IOException.
* Intended for use from finally blocks.
*
* @param socket
* the socket to close, may be {@code null}
* @since 3.0
*/
public static void closeQuietly(Socket socket){
if (socket != null){
try{
socket.close();
}catch (IOException e){
// Ignored
}
}
}
}