Java ClassLoader Load getStreamForString(String source)

Description

Allows client to get an InputStream for a given URL (any string with a ':') or Path specified as a String.

License

Open Source License

Parameter

Parameter	Description
source	-- String either URL string, or path

Exception

Parameter	Description
IOException	-- Underlying Exception from attempt to open any InputStream
MalformedURLException	-- when the source is interpreted as a URL, but is Malformed
FileNotFoundException	-- when the file is not found as specified, or in the CLASSPATH.

Return

InputStream

Declaration

public static InputStream getStreamForString(String source)
        throws IOException, MalformedURLException, FileNotFoundException 

Method Source Code

//package com.java2s;
/*/*from   ww w  . j av a2 s .c o  m*/
Copyright (C) 2003 EBI, GRL
    
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
    
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.
    
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
 */

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;

public class Main {
    /**
     * Allows client to get an InputStream for a given URL (any string with a ':') or Path specified as a String.
     * If the source is a Path request, and a FileNotFoundException or IOException is encountered for the original source,
     * a second attempt is made to find and open the file from the CLASSPATH.  If this second attempt fails with
     * an IOException, the original FileNotFoundException is thrown.  If the source is a URL request, and any URL
     * related Exception is encountered, a second attempt will be made to open the path portion of the URL from the CLASSPATH.
     * If any exception is encountered, the original URL related Exception will be thrown.
     * @param source -- String either URL string, or path
     * @return InputStream
     * @throws IOException -- Underlying Exception from attempt to open any InputStream
     * @throws MalformedURLException -- when the source is interpreted as a URL, but is Malformed
     * @throws FileNotFoundException --  when the file is not found as specified, or in the CLASSPATH.
     */
    public static InputStream getStreamForString(String source)
            throws IOException, MalformedURLException, FileNotFoundException {
        InputStream ret = null;

        try {
            if (source.indexOf(":") > 1) {
                //URL
                URL url = new URL(source);
                ret = url.openStream();
            } else {
                //file path
                FileInputStream f = new FileInputStream(source);
                ret = f;
            }
        } catch (MalformedURLException e) {

            try {
                ret = getStreamFromClassPath(source);
            } catch (IOException e1) {
                // throw the original MalformedURLException
                throw e;
            }
        } catch (FileNotFoundException e) {
            //try finding the file path in the classpath

            try {
                ret = getStreamFromClassPath(source);
            } catch (IOException e1) {
                // throw the original FileNotFoundException
                throw e;
            }
        } catch (IOException e) {
            try {
                ret = getStreamFromClassPath(source);
            } catch (IOException e1) {
                // throw the original IOException
                throw e;
            }
        }

        if (ret == null)
            throw new IOException("Could not create an InputStream from the specified source " + source + "\n");

        return ret;
    }

    private static InputStream getStreamFromClassPath(String source) throws IOException {
        URL retURL = getURLFromClassPath(source);
        if (retURL == null)
            return null;

        return retURL.openStream();
    }

    private static URL getURLFromClassPath(String source) {
        //remove the protocal: from a URL string, if present
        if (source.indexOf(":") >= 0)
            source = source.substring(source.indexOf(":"));

        return ClassLoader.getSystemResource(source);
    }
}

Related

1. getRootPath()
2. getSimpleName(String fqcn)
3. getSourcesPath()
4. getSSTable(String version, int generation)
5. getStream(final File file)
6. getSystemPath(String inPath)
7. getTestDir(final String name)
8. getTestJson()
9. getTomcatBinaryDistribution()