Description
Copies bytes from the URL
source to a file
destination.
License
Apache License
Parameter
| Parameter | Description |
|---|
| source | the <code>URL</code> to copy bytes from, must not be <code>null</code> |
| destination | the non-directory <code>File</code> to write bytes to (possibly overwriting), must not be <code>null</code> |
Exception
| Parameter | Description |
|---|
| IOException | if an IO error occurs during copying |
Declaration
static void copyURLToFile(URL source, File destination) throws IOException
Method Source Code
//package com.java2s;
/**/*from w w w. j av a2 s . c o m*/
* Licensed to Jasig under one or more contributor license
* agreements. See the NOTICE file distributed with this work
* for additional information regarding copyright ownership.
* Jasig 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.
*/
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
public class Main {
/**
* The default buffer size to use.
*/
private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;
/**
* Copies bytes from the URL <code>source</code> to a file
* <code>destination</code>. The directories up to <code>destination</code>
* will be created if they don't already exist. <code>destination</code>
* will be overwritten if it already exists.
*
* @param source the <code>URL</code> to copy bytes from, must not be <code>null</code>
* @param destination the non-directory <code>File</code> to write bytes to
* (possibly overwriting), must not be <code>null</code>
* @throws IOException if <code>source</code> URL cannot be opened
* @throws IOException if <code>destination</code> is a directory
* @throws IOException if <code>destination</code> cannot be written
* @throws IOException if <code>destination</code> needs creating but can't be
* @throws IOException if an IO error occurs during copying
*/
static void copyURLToFile(URL source, File destination) throws IOException {
InputStream input = source.openStream();
try {
FileOutputStream output = openOutputStream(destination);
try {
copy(input, output);
} finally {
closeQuietly(output);
}
} finally {
closeQuietly(input);
}
}
/**
* Opens a {@link FileOutputStream} for the specified file, checking and
* creating the parent directory if it does not exist.
* <p>
* At the end of the method either the stream will be successfully opened,
* or an exception will have been thrown.
* <p>
* The parent directory will be created if it does not exist.
* The file will be created if it does not exist.
* An exception is thrown if the file object exists but is a directory.
* An exception is thrown if the file exists but cannot be written to.
* An exception is thrown if the parent directory cannot be created.
*
* @param file the file to open for output, must not be <code>null</code>
* @return a new {@link FileOutputStream} for the specified file
* @throws IOException if the file object is a directory
* @throws IOException if the file cannot be written to
* @throws IOException if a parent directory needs creating but that fails
* @since Commons IO 1.3
*/
static FileOutputStream openOutputStream(File file) throws IOException {
if (file.exists()) {
if (file.isDirectory()) {
throw new IOException("File '" + file + "' exists but is a directory");
}
if (file.canWrite() == false) {
throw new IOException("File '" + file + "' cannot be written to");
}
} else {
File parent = file.getParentFile();
if (parent != null && parent.exists() == false) {
if (parent.mkdirs() == false) {
throw new IOException("File '" + file + "' could not be created");
}
}
}
return new FileOutputStream(file);
}
/**
* Copy bytes from an <code>InputStream</code> to an
* <code>OutputStream</code>.
* <p>
* This method buffers the input internally, so there is no need to use a
* <code>BufferedInputStream</code>.
* <p>
* Large streams (over 2GB) will return a bytes copied value of
* <code>-1</code> after the copy has completed since the correct
* number of bytes cannot be returned as an int. For large streams
* use the <code>copyLarge(InputStream, OutputStream)</code> method.
*
* @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 NullPointerException if the input or output is null
* @throws IOException if an I/O error occurs
* @throws ArithmeticException if the byte count is too large
* @since Commons IO 1.1
*/
static int copy(InputStream input, OutputStream output) throws IOException {
long count = copyLarge(input, output);
if (count > Integer.MAX_VALUE) {
return -1;
}
return (int) count;
}
/**
* Unconditionally close an <code>OutputStream</code>.
* <p>
* Equivalent to {@link OutputStream#close()}, except any exceptions will be ignored.
* This is typically used in finally blocks.
*
* @param output the OutputStream to close, may be null or already closed
*/
static void closeQuietly(OutputStream output) {
try {
if (output != null) {
output.close();
}
} catch (IOException ioe) {
// ignore
}
}
/**
* Unconditionally close an <code>InputStream</code>.
* <p>
* Equivalent to {@link InputStream#close()}, except any exceptions will be ignored.
* This is typically used in finally blocks.
*
* @param input the InputStream to close, may be null or already closed
*/
static void closeQuietly(InputStream input) {
try {
if (input != null) {
input.close();
}
} catch (IOException ioe) {
// ignore
}
}
/**
* Copy bytes from a large (over 2GB) <code>InputStream</code> to an
* <code>OutputStream</code>.
* <p>
* This method buffers the input internally, so there is no need to use a
* <code>BufferedInputStream</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 NullPointerException if the input or output is null
* @throws IOException if an I/O error occurs
* @since Commons IO 1.3
*/
static long copyLarge(InputStream input, OutputStream output) throws IOException {
byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
long count = 0;
int n = 0;
while (-1 != (n = input.read(buffer))) {
output.write(buffer, 0, n);
count += n;
}
return count;
}
}
Related
- copyRemoteFile(URL url, File localFile)
- copyResource(URL from, File to)
- copyResource(URL resource, File destination)
- copyUrlBinaryFile(String fileName, String sourceUrlPath, String destPath)
- copyURLToFile(final URL source, final File destination)