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Java example source code file (FtpURL.java)

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

Learn more about this Java project at its project page.

Java - Java tags/keywords

bufferedreader, connection, cwd, error, exception, ftpserver, ioexception, mar, net, network, pasv, port, printwriter, runtimeexception, socket, string

The FtpURL.java Java example source code

/*
 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import java.io.*;
import java.net.*;

/*
 * @test
 * @bug 4398880
 * @summary FTP URL processing modified to conform to RFC 1738
 */

public class FtpURL {
    /**
     * A class that simulates, on a separate, an FTP server.
     */

    private class FtpServer extends Thread {
        private ServerSocket    server;
        private int port;
        private boolean done = false;
        private boolean portEnabled = true;
        private boolean pasvEnabled = true;
        private String username;
        private String password;
        private String cwd;
        private String filename;
        private String type;
        private boolean list = false;

        /**
         * This Inner class will handle ONE client at a time.
         * That's where 99% of the protocol handling is done.
         */

        private class FtpServerHandler {
            BufferedReader in;
            PrintWriter out;
            Socket client;
            private final int ERROR = 0;
            private final int USER = 1;
            private final int PASS = 2;
            private final int CWD = 3;
            private final int CDUP = 4;
            private final int PWD = 5;
            private final int TYPE = 6;
            private final int NOOP = 7;
            private final int RETR = 8;
            private final int PASV = 9;
            private final int PORT = 10;
            private final int LIST = 11;
            private final int REIN = 12;
            private final int QUIT = 13;
            private final int STOR = 14;
            private final int NLST = 15;
            private final int RNFR = 16;
            private final int RNTO = 17;
            String[] cmds = { "USER", "PASS", "CWD", "CDUP", "PWD", "TYPE",
                              "NOOP", "RETR", "PASV", "PORT", "LIST", "REIN",
                              "QUIT", "STOR", "NLST", "RNFR", "RNTO" };
            private String arg = null;
            private ServerSocket pasv = null;
            private int data_port = 0;
            private InetAddress data_addr = null;

            /**
             * Parses a line to match it with one of the supported FTP commands.
             * Returns the command number.
             */

            private int parseCmd(String cmd) {
                if (cmd == null || cmd.length() < 3)
                    return ERROR;
                int blank = cmd.indexOf(' ');
                if (blank < 0)
                    blank = cmd.length();
                if (blank < 3)
                    return ERROR;
                String s = cmd.substring(0, blank);
                if (cmd.length() > blank+1)
                    arg = cmd.substring(blank+1, cmd.length());
                else
                    arg = null;
                for (int i = 0; i < cmds.length; i++) {
                    if (s.equalsIgnoreCase(cmds[i]))
                        return i+1;
                }
                return ERROR;
            }

            public FtpServerHandler(Socket cl) {
                client = cl;
            }

            protected boolean isPasvSet() {
                if (pasv != null && !pasvEnabled) {
                    try {
                        pasv.close();
                    } catch (IOException ex) {
                    }
                    pasv = null;
                }
                if (pasvEnabled && pasv != null)
                    return true;
                return false;
            }

            /**
             * Open the data socket with the client. This can be the
             * result of a "PASV" or "PORT" command.
             */

            protected OutputStream getOutDataStream() {
                try {
                    if (isPasvSet()) {
                        Socket s = pasv.accept();
                        return s.getOutputStream();
                    }
                    if (data_addr != null) {
                        Socket s = new Socket(data_addr, data_port);
                        data_addr = null;
                        data_port = 0;
                        return s.getOutputStream();
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
                return null;
            }

            protected InputStream getInDataStream() {
                try {
                    if (isPasvSet()) {
                        Socket s = pasv.accept();
                        return s.getInputStream();
                    }
                    if (data_addr != null) {
                        Socket s = new Socket(data_addr, data_port);
                        data_addr = null;
                        data_port = 0;
                        return s.getInputStream();
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
                return null;
            }

            /**
             * Handles the protocol exchange with the client.
             */

            public void run() {
                boolean done = false;
                String str;
                int res;
                boolean logged = false;
                boolean waitpass = false;

                try {
                    in = new BufferedReader(new InputStreamReader(client.getInputStream()));
                    out = new PrintWriter(client.getOutputStream(), true);
                    out.println("220 tatooine FTP server (SunOS 5.8) ready.");
                } catch (Exception ex) {
                    return;
                }
                synchronized (FtpServer.this) {
                  while (!done) {
                    try {
                        str = in.readLine();
                        res = parseCmd(str);
                        if ((res > PASS && res != QUIT) && !logged) {
                            out.println("530 Not logged in.");
                            continue;
                        }
                        switch (res) {
                        case ERROR:
                            out.println("500 '" + str + "': command not understood.");
                            break;
                        case USER:
                            if (!logged && !waitpass) {
                                username = str.substring(5);
                                password = null;
                                cwd = null;
                                if ("user2".equals(username)) {
                                    out.println("230 Guest login ok, access restrictions apply.");
                                    logged = true;
                                } else {
                                    out.println("331 Password required for " + arg);
                                    waitpass = true;
                                }
                            } else {
                                out.println("503 Bad sequence of commands.");
                            }
                            break;
                        case PASS:
                            if (!logged && waitpass) {
                                out.println("230 Guest login ok, access restrictions apply.");
                                password = str.substring(5);
                                logged = true;
                                waitpass = false;
                            } else
                                out.println("503 Bad sequence of commands.");
                            break;
                        case QUIT:
                            out.println("221 Goodbye.");
                            out.flush();
                            out.close();
                            if (pasv != null)
                                pasv.close();
                            done = true;
                            break;
                        case TYPE:
                            out.println("200 Type set to " + arg + ".");
                            type = arg;
                            break;
                        case CWD:
                            out.println("250 CWD command successful.");
                            if (cwd == null)
                                cwd = str.substring(4);
                            else
                                cwd = cwd + "/" + str.substring(4);
                            break;
                        case CDUP:
                            out.println("250 CWD command successful.");
                            break;
                        case PWD:
                            out.println("257 \"" + cwd + "\" is current directory");
                            break;
                        case PASV:
                            if (!pasvEnabled) {
                                out.println("500 PASV is disabled, use PORT instead.");
                                continue;
                            }
                            try {
                                if (pasv == null)
                                    pasv = new ServerSocket(0);
                                int port = pasv.getLocalPort();
                                out.println("227 Entering Passive Mode (127,0,0,1," +
                                            (port >> 8) + "," + (port & 0xff) +")");
                            } catch (IOException ssex) {
                                out.println("425 Can't build data connection: Connection refused.");
                            }
                            break;
                        case PORT:
                            if (!portEnabled) {
                                out.println("500 PORT is disabled, use PASV instead");
                                continue;
                            }
                            StringBuffer host;
                            int i=0, j=4;
                            while (j>0) {
                                i = arg.indexOf(',', i+1);
                                if (i < 0)
                                    break;
                                j--;
                            }
                            if (j != 0) {
                                out.println("500 '" + arg + "': command not understood.");
                                continue;
                            }
                            try {
                                host = new StringBuffer(arg.substring(0,i));
                                for (j=0; j < host.length(); j++)
                                    if (host.charAt(j) == ',')
                                        host.setCharAt(j, '.');
                                String ports = arg.substring(i+1);
                                i = ports.indexOf(',');
                                data_port = Integer.parseInt(ports.substring(0,i)) << 8;
                                data_port += (Integer.parseInt(ports.substring(i+1)));
                                data_addr = InetAddress.getByName(host.toString());
                                out.println("200 Command okay.");
                            } catch (Exception ex3) {
                                data_port = 0;
                                data_addr = null;
                                out.println("500 '" + arg + "': command not understood.");
                            }
                            break;
                        case RETR:
                            {
                                filename = str.substring(5);
                                OutputStream dout = getOutDataStream();
                                if (dout != null) {
                                    out.println("200 Command okay.");
                                    PrintWriter pout = new PrintWriter(new BufferedOutputStream(dout));
                                    pout.println("Hello World!");
                                    pout.flush();
                                    pout.close();
                                    list = false;
                                } else
                                    out.println("425 Can't build data connection: Connection refused.");
                            }
                            break;
                        case NLST:
                            filename = arg;
                        case LIST:
                            {
                                OutputStream dout = getOutDataStream();
                                if (dout != null) {
                                    out.println("200 Command okay.");
                                    PrintWriter pout = new PrintWriter(new BufferedOutputStream(dout));
                                    pout.println("total 130");
                                    pout.println("drwxrwxrwt   7 sys      sys          577 May 12 03:30 .");
                                    pout.println("drwxr-xr-x  39 root     root        1024 Mar 27 12:55 ..");
                                    pout.println("drwxrwxr-x   2 root     root         176 Apr 10 12:02 .X11-pipe");
                                    pout.println("drwxrwxr-x   2 root     root         176 Apr 10 12:02 .X11-unix");
                                    pout.println("drwxrwxrwx   2 root     root         179 Mar 30 15:09 .pcmcia");
                                    pout.println("drwxrwxrwx   2 jladen   staff        117 Mar 30 18:18 .removable");
                                    pout.println("drwxrwxrwt   2 root     root         327 Mar 30 15:08 .rpc_door");
                                    pout.println("-rw-r--r--   1 root     other         21 May  5 16:59 hello2.txt");
                                    pout.println("-rw-rw-r--   1 root     sys         5968 Mar 30 15:08 ps_data");
                                    pout.flush();
                                    pout.close();
                                    list = true;
                                    try {
                                        FtpServer.this.wait ();
                                    } catch (Exception e) {}
                                } else
                                    out.println("425 Can't build data connection: Connection refused.");
                            }
                            break;
                        case STOR:
                            {
                                InputStream is = getInDataStream();
                                if (is != null) {
                                    out.println("200 Command okay.");
                                    BufferedInputStream din = new BufferedInputStream(is);
                                    int val;
                                    do {
                                        val = din.read();
                                    } while (val != -1);
                                    din.close();
                                } else
                                    out.println("425 Can't build data connection: Connection refused.");
                            }
                            break;
                        }
                    } catch (IOException ioe) {
                        ioe.printStackTrace();
                        try {
                            out.close();
                        } catch (Exception ex2) {
                        }
                        done = true;
                    }
                  }
                }
            }
        }

        public FtpServer(int port) {
            this.port = port;
            try {
              server = new ServerSocket(port);
            } catch (IOException e) {
            }
        }

        public FtpServer() {
            this(21);
        }

        public int getPort() {
            if (server != null)
                return server.getLocalPort();
            return 0;
        }

        /**
         * A way to tell the server that it can stop.
         */
        synchronized public void terminate() {
            done = true;
        }

        synchronized public void setPortEnabled(boolean ok) {
            portEnabled = ok;
        }

        synchronized public void setPasvEnabled(boolean ok) {
            pasvEnabled = ok;
        }

        String getUsername() {
            return username;
        }

        String getPassword() {
            return password;
        }

        String pwd() {
            return cwd;
        }

        String getFilename() {
            return filename;
        }

        String getType() {
            return type;
        }

        synchronized boolean getList() {
            notify ();
            return list;
        }

        /*
         * All we got to do here is create a ServerSocket and wait for connections.
         * When a connection happens, we just have to create a thread that will
         * handle it.
         */
        public void run() {
            try {
                Socket client;
                for (int i=0; i<2; i++) {
                    client = server.accept();
                    (new FtpServerHandler(client)).run();
                }
            } catch(Exception e) {
            } finally {
                try { server.close(); } catch (IOException unused) {}
            }
        }
    }
    public static void main(String[] args) throws Exception {
        FtpURL test = new FtpURL();
    }

    public FtpURL() throws Exception {
        FtpServer server = new FtpServer(0);
        BufferedReader in = null;
        try {
            server.start();
            int port = server.getPort();

            // Now let's check the URL handler

            URL url = new URL("ftp://user:password@localhost:" + port + "/%2Fetc/motd;type=a");
            URLConnection con = url.openConnection();
            in = new BufferedReader(new InputStreamReader(con.getInputStream()));
            String s;
            do {
                s = in.readLine();
            } while (s != null);
            if (!("user".equals(server.getUsername())))
                throw new RuntimeException("Inccorect username received");
            if (!("password".equals(server.getPassword())))
                throw new RuntimeException("Inccorect password received");
            if (!("/etc".equals(server.pwd())))
                throw new RuntimeException("Inccorect directory received");
            if (!("motd".equals(server.getFilename())))
                throw new RuntimeException("Inccorect username received");
            if (!("A".equals(server.getType())))
                throw new RuntimeException("Incorrect type received");

            in.close();
            // We're done!

            // Second URL test
            port = server.getPort();

            // Now let's check the URL handler

            url = new URL("ftp://user2:@localhost:" + port + "/%2Fusr/bin;type=d");
            con = url.openConnection();
            in = new BufferedReader(new InputStreamReader(con.getInputStream()));
            do {
                s = in.readLine();
            } while (s != null);
            if (!server.getList())
                throw new RuntimeException(";type=d didn't generate a NLST");
            if (server.getPassword() != null)
                throw new RuntimeException("password should be null!");
            if (! "bin".equals(server.getFilename()))
                throw new RuntimeException("Incorrect filename received");
            if (! "/usr".equals(server.pwd()))
                throw new RuntimeException("Incorrect pwd received");
            // We're done!

        } catch (Exception e) {
            throw new RuntimeException("FTP support error: " + e.getMessage());
        } finally {
            try { in.close(); } catch (IOException unused) {}
            server.terminate();
            server.server.close();
        }
    }
}

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