Commons Net example source code file (DownloadListings.java)

This example Commons Net source code file (DownloadListings.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Net tags/keywords

bufferedreader, downloadlistings, exception, exception, file, file, fileoutputstream, ftpclient, io, net, network, outputstream, printcommandlistener, printcommandlistener, printwriter, string, string

The Commons Net DownloadListings.java source code

/*
 * 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.
 *
 */

package org.apache.commons.net.ftp.parser;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.Reader;
import java.net.Socket;

import org.apache.commons.net.PrintCommandListener;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPCommand;
import org.apache.commons.net.io.Util;

/**
 * Sample class to download LIST and MLSD listings from list of ftp sites.
 */
public class DownloadListings extends FTPClient {
    
    // Also used by MLDSComparison
    static final String DOWNLOAD_DIR = "target/ftptest";

    private PrintCommandListener listener;
    private PrintWriter out;

    private boolean open(String host, int port) throws Exception{
        System.out.println("Connecting to "+host);
        out = new PrintWriter(new FileWriter(new File(DOWNLOAD_DIR, host+"_info.txt")));
        listener = new PrintCommandListener(out);
        addProtocolCommandListener(listener);
        setConnectTimeout(30000);
        try {
            connect(host, port);
        } catch (Exception e) {
            System.out.println(e);
            return false;
        }
        enterLocalPassiveMode(); // this is reset by connect
        System.out.println("Logging in to "+host);
        return login("anonymous", "user@localhost");
    }

    private void info() throws IOException {
        syst();
        help();
        feat();
        removeProtocolCommandListener(listener);
    }

    private void download(String path, int command, File filename) throws Exception {
        Socket socket;
        if ((socket = _openDataConnection_(command, getListArguments(path))) == null) {
            System.out.println(getReplyString());
            return;
        }
        InputStream inputStream = socket.getInputStream();
        OutputStream outputStream = new FileOutputStream(filename);
        Util.copyStream(inputStream, outputStream );
        inputStream.close();
        socket.close();
        outputStream.close();

        if (!completePendingCommand())
        {
            System.out.println(getReplyString());
        }
    }

    public static void main(String[] args) throws Exception {
        String host;// = "ftp.funet.fi";
        int port = 21;
        String path;// = "/";

        new File(DOWNLOAD_DIR).mkdirs();
        DownloadListings self = new DownloadListings();
        OutputStream os = new FileOutputStream(new File(DOWNLOAD_DIR, "session.log"));
        self.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(os), true));

        Reader is = new FileReader("mirrors.list");
        BufferedReader rdr = new BufferedReader(is);
        String line;
        while((line=rdr.readLine()) != null){
            if (line.startsWith("ftp")){
                String []parts = line.split("\\s+");
                String target = parts[2];
                host = target.substring("ftp://".length());
                int slash = host.indexOf('/');
                path = host.substring(slash);
                host = host.substring(0,slash);
                System.out.println(host+ " "+path);
                if (self.open(host, port)) {
                    try {
                        self.info();
                        self.download(path, FTPCommand.LIST, new File(DOWNLOAD_DIR, host+"_list.txt"));
                        self.download(path, FTPCommand.MLSD, new File(DOWNLOAD_DIR, host+"_mlsd.txt"));
                    } catch (Exception e) {
                        e.printStackTrace();
                    } finally {
                        self.disconnect();
                    }
                    self.removeProtocolCommandListener(self.listener);
                    self.out.close();
                }
            }
        }
        os.close();
    }
}