如何使用java連接多個ftp服務器

Question

我是新來的ftp概念。我需要從一個FTP服務器將文件移動到另一個FTP服務器，用java程序 你可以給我一個想法如何做到這一點

Answer 1

這裏是你正在尋找一個很好的例子：http://commons.apache.org/proper/commons-net/examples/ftp/ServerToServerFTP.java

使用Apache通用淨。

以下是完整的代碼（來自鏈接）：

/* 
* 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 examples.ftp; 

import java.io.IOException; 
import java.io.PrintWriter; 
import java.net.InetAddress; 

import org.apache.commons.net.PrintCommandListener; 
import org.apache.commons.net.ProtocolCommandListener; 
import org.apache.commons.net.ftp.FTPClient; 
import org.apache.commons.net.ftp.FTPReply; 

/*** 
* This is an example program demonstrating how to use the FTPClient class. 
* This program arranges a server to server file transfer that transfers 
* a file from host1 to host2. Keep in mind, this program might only work 
* if host2 is the same as the host you run it on (for security reasons, 
* some ftp servers only allow PORT commands to be issued with a host 
* argument equal to the client host). 
* <p> 
* Usage: ftp <host1> <user1> <pass1> <file1> <host2> <user2> <pass2> <file2> 
* <p> 
***/ 
public final class ServerToServerFTP 
{ 

    public static void main(String[] args) 
    { 
     String server1, username1, password1, file1; 
     String server2, username2, password2, file2; 
     String [] parts; 
     int port1=0, port2=0; 
     FTPClient ftp1, ftp2; 
     ProtocolCommandListener listener; 

     if (args.length < 8) 
     { 
      System.err.println(
       "Usage: ftp <host1> <user1> <pass1> <file1> <host2> <user2> <pass2> <file2>" 
      ); 
      System.exit(1); 
     } 

     server1 = args[0]; 
     parts = server1.split(":"); 
     if (parts.length == 2) { 
      server1=parts[0]; 
      port1 = Integer.parseInt(parts[1]); 
     } 
     username1 = args[1]; 
     password1 = args[2]; 
     file1 = args[3]; 
     server2 = args[4]; 
     parts = server2.split(":"); 
     if (parts.length == 2) { 
      server2=parts[0]; 
      port2 = Integer.parseInt(parts[1]); 
     } 
     username2 = args[5]; 
     password2 = args[6]; 
     file2 = args[7]; 

     listener = new PrintCommandListener(new PrintWriter(System.out), true); 
     ftp1 = new FTPClient(); 
     ftp1.addProtocolCommandListener(listener); 
     ftp2 = new FTPClient(); 
     ftp2.addProtocolCommandListener(listener); 

     try 
     { 
      int reply; 
      if (port1 > 0) { 
       ftp1.connect(server1, port1); 
      } else { 
       ftp1.connect(server1); 
      } 
      System.out.println("Connected to " + server1 + "."); 

      reply = ftp1.getReplyCode(); 

      if (!FTPReply.isPositiveCompletion(reply)) 
      { 
       ftp1.disconnect(); 
       System.err.println("FTP server1 refused connection."); 
       System.exit(1); 
      } 
     } 
     catch (IOException e) 
     { 
      if (ftp1.isConnected()) 
      { 
       try 
       { 
        ftp1.disconnect(); 
       } 
       catch (IOException f) 
       { 
        // do nothing 
       } 
      } 
      System.err.println("Could not connect to server1."); 
      e.printStackTrace(); 
      System.exit(1); 
     } 

     try 
     { 
      int reply; 
      if (port2 > 0) { 
       ftp2.connect(server2, port2); 
      } else { 
       ftp2.connect(server2); 
      } 
      System.out.println("Connected to " + server2 + "."); 

      reply = ftp2.getReplyCode(); 

      if (!FTPReply.isPositiveCompletion(reply)) 
      { 
       ftp2.disconnect(); 
       System.err.println("FTP server2 refused connection."); 
       System.exit(1); 
      } 
     } 
     catch (IOException e) 
     { 
      if (ftp2.isConnected()) 
      { 
       try 
       { 
        ftp2.disconnect(); 
       } 
       catch (IOException f) 
       { 
        // do nothing 
       } 
      } 
      System.err.println("Could not connect to server2."); 
      e.printStackTrace(); 
      System.exit(1); 
     } 

__main: 
     try 
     { 
      if (!ftp1.login(username1, password1)) 
      { 
       System.err.println("Could not login to " + server1); 
       break __main; 
      } 

      if (!ftp2.login(username2, password2)) 
      { 
       System.err.println("Could not login to " + server2); 
       break __main; 
      } 

      // Let's just assume success for now. 
      ftp2.enterRemotePassiveMode(); 

      ftp1.enterRemoteActiveMode(InetAddress.getByName(ftp2.getPassiveHost()), 
             ftp2.getPassivePort()); 

      // Although you would think the store command should be sent to server2 
      // first, in reality, ftp servers like wu-ftpd start accepting data 
      // connections right after entering passive mode. Additionally, they 
      // don't even send the positive preliminary reply until after the 
      // transfer is completed (in the case of passive mode transfers). 
      // Therefore, calling store first would hang waiting for a preliminary 
      // reply. 
      if (ftp1.remoteRetrieve(file1) && ftp2.remoteStoreUnique(file2)) 
      { 
       //  if(ftp1.remoteRetrieve(file1) && ftp2.remoteStore(file2)) { 
       // We have to fetch the positive completion reply. 
       ftp1.completePendingCommand(); 
       ftp2.completePendingCommand(); 
      } 
      else 
      { 
       System.err.println(
        "Couldn't initiate transfer. Check that filenames are valid."); 
       break __main; 
      } 

     } 
     catch (IOException e) 
     { 
      e.printStackTrace(); 
      System.exit(1); 
     } 
     finally 
     { 
      try 
      { 
       if (ftp1.isConnected()) 
       { 
        ftp1.logout(); 
        ftp1.disconnect(); 
       } 
      } 
      catch (IOException e) 
      { 
       // do nothing 
      } 

      try 
      { 
       if (ftp2.isConnected()) 
       { 
        ftp2.logout(); 
        ftp2.disconnect(); 
       } 
      } 
      catch (IOException e) 
      { 
       // do nothing 
      } 
     } 
    } 
}