Java URL to InputStream openStream(URL url)

Description

open Stream

License

Apache License

Declaration

public static InputStream openStream(URL url) throws IOException 

Method Source Code

//package com.java2s;
/*/*from w ww  .j  a v a2s .com*/
 * 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.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.JarURLConnection;

import java.net.URL;
import java.net.URLConnection;

public class Main {
    public static InputStream openStream(URL url) throws IOException {
        // Handle file:<relative path> which strictly speaking is not a valid file URL  
        File file = toFile(url);
        if (file != null) {
            return new FileInputStream(file);
        }
        URLConnection connection = url.openConnection();
        if (connection instanceof JarURLConnection) {
            // See http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5041014
            connection.setUseCaches(false);
        }
        InputStream is = connection.getInputStream();
        return is;
    }

    /**
     * Returns the File object representing  the given URL.
     *
     * @param url
     * @return
     */
    public static File toFile(URL url) {
        if (url == null || !url.getProtocol().equals("file")) {
            return null;
        } else {
            String filename = url.getFile().replace('/', File.separatorChar);
            int pos = 0;
            while ((pos = filename.indexOf('%', pos)) >= 0) {
                if (pos + 2 < filename.length()) {
                    String hexStr = filename.substring(pos + 1, pos + 3);
                    char ch = (char) Integer.parseInt(hexStr, 16);
                    filename = filename.substring(0, pos) + ch + filename.substring(pos + 3);
                }
            }
            return new File(filename);
        }
    }
}

Related

1. openFileOrURL(String fileNameOrUrl)
2. openFileOrURL(String name)
3. openInputStream(URL url)
4. openStream(String urlStr)
5. openStream(URL url)
6. openStream(URL url)
7. openStream(URL url)
8. openStream(URL url)
9. openStream(URL url)