Description
Converts each of an array of
URL to a
File.
License
Apache License
Parameter
| Parameter | Description |
|---|
| urls | the file URLs to convert, <code>null</code> returns empty array |
Exception
| Parameter | Description |
|---|
| IllegalArgumentException | if any file is incorrectly encoded |
Return
a non-
null array of Files matching the input, with a
null item if there was a
null at that index in the input array
Declaration
public static File[] toFiles(URL[] urls)
Method Source Code
//package com.java2s;
/*//from w w w . ja v a 2s . c o m
* 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.
*/
import java.io.*;
import java.net.URL;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
public class Main {
/**
* An empty array of type <code>File</code>.
*/
public static final File[] EMPTY_FILE_ARRAY = new File[0];
/**
* The UTF-8 character set, used to decode octets in URLs.
*/
private static final Charset UTF8 = Charset.forName("UTF-8");
/**
* Converts each of an array of <code>URL</code> to a <code>File</code>.
* <p>
* Returns an array of the same size as the input.
* If the input is <code>null</code>, an empty array is returned.
* If the input contains <code>null</code>, the output array contains <code>null</code> at the same
* index.
* <p>
* This method will decode the URL.
* Syntax such as <code>file:///my%20docs/file.txt</code> will be
* correctly decoded to <code>/my docs/file.txt</code>.
*
* @param urls the file URLs to convert, <code>null</code> returns empty array
* @return a non-<code>null</code> array of Files matching the input, with a <code>null</code> item
* if there was a <code>null</code> at that index in the input array
* @throws IllegalArgumentException if any file is not a URL file
* @throws IllegalArgumentException if any file is incorrectly encoded
* @since Commons IO 1.1
*/
public static File[] toFiles(URL[] urls) {
if (urls == null || urls.length == 0) {
return EMPTY_FILE_ARRAY;
}
File[] files = new File[urls.length];
for (int i = 0; i < urls.length; i++) {
URL url = urls[i];
if (url != null) {
if (url.getProtocol().equals("file") == false) {
throw new IllegalArgumentException("URL could not be converted to a File: " + url);
}
files[i] = toFile(url);
}
}
return files;
}
/**
* Convert from a <code>URL</code> to a <code>File</code>.
* <p>
* From version 1.1 this method will decode the URL.
* Syntax such as <code>file:///my%20docs/file.txt</code> will be
* correctly decoded to <code>/my docs/file.txt</code>. Starting with version
* 1.5, this method uses UTF-8 to decode percent-encoded octets to characters.
* Additionally, malformed percent-encoded octets are handled leniently by
* passing them through literally.
*
* @param url the file URL to convert, <code>null</code> returns <code>null</code>
* @return the equivalent <code>File</code> object, or <code>null</code>
* if the URL's protocol is not <code>file</code>
*/
public static File toFile(URL url) {
if (url == null || !"file".equalsIgnoreCase(url.getProtocol())) {
return null;
} else {
String filename = url.getFile().replace('/', File.separatorChar);
filename = decodeUrl(filename);
return new File(filename);
}
}
/**
* Decodes the specified URL as per RFC 3986, i.e. transforms
* percent-encoded octets to characters by decoding with the UTF-8 character
* set. This function is primarily intended for usage with
* {@link java.net.URL} which unfortunately does not enforce proper URLs. As
* such, this method will leniently accept invalid characters or malformed
* percent-encoded octets and simply pass them literally through to the
* result string. Except for rare edge cases, this will make unencoded URLs
* pass through unaltered.
*
* @param url The URL to decode, may be <code>null</code>.
* @return The decoded URL or <code>null</code> if the input was
* <code>null</code>.
*/
static String decodeUrl(String url) {
String decoded = url;
if (url != null && url.indexOf('%') >= 0) {
int n = url.length();
StringBuffer buffer = new StringBuffer();
ByteBuffer bytes = ByteBuffer.allocate(n);
for (int i = 0; i < n;) {
if (url.charAt(i) == '%') {
try {
do {
byte octet = (byte) Integer.parseInt(url.substring(i + 1, i + 3), 16);
bytes.put(octet);
i += 3;
} while (i < n && url.charAt(i) == '%');
continue;
} catch (RuntimeException e) {
// malformed percent-encoded octet, fall through and
// append characters literally
} finally {
if (bytes.position() > 0) {
bytes.flip();
buffer.append(UTF8.decode(bytes).toString());
bytes.clear();
}
}
}
buffer.append(url.charAt(i++));
}
decoded = buffer.toString();
}
return decoded;
}
}
Related
- toChars(byte[] bytes)
- toDirectBuffer(String s)
- toDoubleArray(byte[] data)
- toFile(URL url)
- toFile(URL url)
- toFloat(byte[] bytes)
- toFloat(final byte[] b)
- toFloatArray(int[] intArray)
- toFloatBytes(List datas)