Java URL to File Name getFileName(final CharSequence url)

Description

Returns the unqualified file name for the passed URL

License

Apache License

Parameter

Parameter	Description
url	The URL to the file name for

Return

The file name

Declaration

public static String getFileName(final CharSequence url) 

Method Source Code

//package com.java2s;
/*/*from   w w  w.j  a va2 s . com*/
 * Copyright 2015 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.File;

import java.net.URI;
import java.net.URL;

public class Main {
    /**
     * Returns the unqualified file name for the passed URL
     * @param url The URL to the file name for
     * @return The file name
     */
    public static String getFileName(final CharSequence url) {
        return getFileName(toURL(url));
    }

    /**
     * Returns the unqualified file name for the passed URL
     * @param url The URL to the file name for
     * @return The file name
     */
    public static String getFileName(final URL url) {
        if (url == null)
            throw new IllegalArgumentException("The passed URL was null");
        return new File(url.getFile()).getName();
    }

    /**
     * Returns the URL for the passed file
     * @param file the file to get the URL for
     * @return a URL for the passed file
     */
    public static URL toURL(File file) {
        try {
            return nvl(file, "Passed file was null").toURI().toURL();
        } catch (Exception e) {
            throw new RuntimeException("Failed to get URL for file [" + file + "]", e);
        }
    }

    /**
     * Creates a URL from the passed string 
     * @param urlStr A char sequence containing a URL representation
     * @return a URL
     */
    public static URL toURL(final CharSequence urlStr) {
        if (urlStr == null || urlStr.toString().trim().isEmpty())
            throw new IllegalArgumentException("The passed URL stringy was null or empty");
        try {
            if (isFile(urlStr))
                return toURL(new File(urlStr.toString()).getAbsoluteFile());
            return new URL(nvl(urlStr, "Passed string was null").toString());
        } catch (Exception e) {
            throw new RuntimeException("Failed to create URL from string [" + urlStr + "]", e);
        }
    }

    /**
     * Creates a URI from the passed string 
     * @param uriStr A char sequence containing a URI representation
     * @return a URI
     */
    public static URI toURI(CharSequence uriStr) {
        try {
            return new URI(nvl(uriStr, "Passed string was null").toString());
        } catch (Exception e) {
            throw new RuntimeException("Failed to create URL from string [" + uriStr + "]", e);
        }
    }

    /**
     * Tests the passed object for nullness. Throws an {@link IllegalArgumentException} if the object is null 
     * @param t  The object to test
     * @param message The message to associate with the exception, Ignored if null
     * @return the object passed in if not null
     */
    public static <T> T nvl(T t, String message) {
        if (t == null)
            throw new IllegalArgumentException(message != null ? message : "Null parameter");
        return t;
    }

    /**
     * Determines if the passed stringy represents an existing file name
     * @param urlStr The stringy to test
     * @return true if the passed stringy represents an existing file name, false otherwise
     */
    public static boolean isFile(final CharSequence urlStr) {
        if (urlStr == null || urlStr.toString().trim().isEmpty())
            throw new IllegalArgumentException("The passed URL stringy was null or empty");
        return new File(urlStr.toString().trim()).exists();
    }
}

Related

1. getFileFromUrl(String urlPath)
2. getFileFromURL(URL url)
3. getFileFromURL(URL url)
4. getFileFromUrl(URL url)
5. getFileFromURL(URL urlToDecode)
6. getFileName(final URL url)
7. getFilename(final URL url)
8. getFilename(final URL url, int maxLength)
9. getFileName(HttpURLConnection conn)