com.krawler.runtime.utils.URLClassLoaderUtil.java Source code

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Here is the source code for com.krawler.runtime.utils.URLClassLoaderUtil.java

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/*
 * Copyright (C) 2012  Krawler Information Systems Pvt Ltd
 * All rights reserved.
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

package com.krawler.runtime.utils;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;

import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 *
 * @author shayanthan.k
 *
 */
public class URLClassLoaderUtil extends URLClassLoader {

    public URLClassLoaderUtil(URL[] urls) {
        super(urls);
    }

    private static Log log = LogFactory.getLog(URLClassLoaderUtil.class);

    private static final Class[] parameters = new Class[] { URL.class };

    public void addFile(String path) throws Exception {
        String urlPath = "jar:file://" + path + "!/";
        try {
            this.addJarURL(new URL(urlPath));

        } catch (Exception e) {
            throw e;
        }
    }

    public void addFile(File f) throws Exception {
        this.addJarURL(f.toURL());
    }

    public void addJarURL(URL u) throws Exception {
        try {

            URLClassLoader sysLoader = (URLClassLoader) ClassLoader.getSystemClassLoader();
            URL urls[] = sysLoader.getURLs();
            for (int i = 0; i < urls.length; i++) {
                if (StringUtils.equalsIgnoreCase(urls[i].toString(), u.toString())) {
                    if (log.isDebugEnabled()) {
                        log.debug("URL " + u + " is already in the CLASSPATH");
                    }
                    return;
                }
            }
            Class sysclass = URLClassLoader.class;
            Method method = sysclass.getDeclaredMethod("addURL", parameters);
            method.setAccessible(true);
            method.invoke(sysLoader, new Object[] { u });
        } catch (Exception e) {
            e.printStackTrace();
            throw new Exception("Error, could not add URL to system classloader" + e.getMessage());
        }

    }

    public static void main(String[] args) {
        try {
            URLClassLoaderUtil urlcu = new URLClassLoaderUtil(
                    new URL[] { new URL("file:///home/krawler/KrawlerJsonLib.jar") });
            urlcu.addFile("/home/krawler/KrawlerJsonLib.jar");
            Class c = Class.forName("com.krawler.utils.json.base.JSONObject");
            System.out.print(c.getCanonicalName());

        } catch (Exception ex) {
            Logger.getLogger(URLClassLoaderUtil.class.getName()).log(Level.SEVERE, null, ex);
        }

    }
}