Java FTPClient implements file upload and download

In the JAVA program, you often need to deal with FTP, such as uploading and downloading files to the FTP server. This article briefly describes how to make use of FTPClient in jakarta commons (in the commons-net package) to upload and download files.
The jar packages used are:  
commons-net-1.4.1.jar  
jakarta-oro.jar  
1. Upload files

  File upload source code  
    /** 
   * Description:  to FTP Server upload file  
   * @Version1.0 
   * @param url FTP The server hostname 
   * @param port FTP Server port  
   * @param username FTP Login account  
   * @param password FTP The login password  
   * @param path FTP Server save directory  
   * @param filename  Uploaded to the FTP The file name on the server  
   * @param input  The input stream  
   * @return  Successfully returns true Otherwise return false 
   */ 
  public static boolean uploadFile( 
    String url,//FTP The server hostname 
    int port,//FTP Server port  
    String username, // FTP Login account  
    String password, //FTP The login password  
    String path, //FTP Server save directory  
    String filename, // Uploaded to the FTP The file name on the server  
    InputStream input //  The input stream  
    ) { 
   boolean success = false; 
   FTPClient ftp = new FTPClient(); 
   try { 
    int reply; 
    ftp.connect(url, port);// The connection FTP The server   
    // If the default port is used, it can be used ftp.connect(url) The way of direct connection FTP The server   
    ftp.login(username, password);// The login   
    reply = ftp.getReplyCode(); 
    if (!FTPReply.isPositiveCompletion(reply)) { 
     ftp.disconnect(); 
     return success; 
    } 
    ftp.changeWorkingDirectory(path); 
    ftp.storeFile(filename, input);    
     
    input.close(); 
    ftp.logout(); 
    success = true; 
   } catch (IOException e) { 
    e.printStackTrace(); 
   } finally { 
    if (ftp.isConnected()) { 
     try { 
      ftp.disconnect(); 
     } catch (IOException ioe) { 
     } 
    } 
   } 
   return success; 
  } 

Here are the test cases for file upload:

 /** 
  *  Upload the local file to FTP On the server  
  * 
  */ 
 public void testUpLoadFromDisk(){ 
  try { 
   FileInputStream in=new FileInputStream(new File("D:/test.txt")); 
   boolean flag = uploadFile("127.0.0.1", 21, "administrator", "zyuc2011", "test", "test.txt", in); 
   System.out.println(flag); 
  } catch (FileNotFoundException e) { 
   e.printStackTrace(); 
  }  
 } 
 /** 
  *  in FTP Generate on the server 1 File and will 1 Two strings are written to the file  
  * 
  */ 
 public void testUpLoadFromString(){ 
  try { 
   String str = " This is the string to write! "; 
   InputStream input = new ByteArrayInputStream(str.getBytes("utf-8")); 
   boolean flag = uploadFile("127.0.0.1", 21, "administrator", "zyuc2011", "test", "test.txt", input); 
   System.out.println(flag); 
  } catch (UnsupportedEncodingException e) { 
   e.printStackTrace(); 
  } 
 } 

2. File download
File download the source code    

 /** 
  * Description:  from FTP Server download file  
  * @Version1.0 
  * @param url FTP The server hostname 
  * @param port FTP Server port  
  * @param username FTP Login account  
  * @param password FTP The login password  
  * @param remotePath FTP The relative path on the server  
  * @param fileName  The file name to download  
  * @param localPath  Save to the local path after downloading  
  * @return 
  */ 
 public static boolean downFile( 
   String url, //FTP The server hostname 
   int port,//FTP Server port  
   String username, //FTP Login account  
   String password, //FTP The login password  
   String remotePath,//FTP The relative path on the server  
   String fileName,// The file name to download  
   String localPath// Save to the local path after downloading  
   ) { 
  boolean success = false; 
  FTPClient ftp = new FTPClient(); 
  try { 
   int reply; 
   ftp.connect(url, port); 
   // If the default port is used, it can be used ftp.connect(url) The way of direct connection FTP The server   
   ftp.login(username, password);// The login   
   reply = ftp.getReplyCode(); 
   if (!FTPReply.isPositiveCompletion(reply)) { 
    ftp.disconnect(); 
    return success; 
   } 
   ftp.changeWorkingDirectory(remotePath);// Transferred to the FTP Server directory   
   FTPFile[] fs = ftp.listFiles(); 
   for(FTPFile ff:fs){ 
    if(ff.getName().equals(fileName)){ 
     File localFile = new File(localPath+"/"+ff.getName()); 
     OutputStream is = new FileOutputStream(localFile);  
     ftp.retrieveFile(ff.getName(), is); 
     is.close(); 
    } 
   } 
    
   ftp.logout(); 
   success = true; 
  } catch (IOException e) { 
   e.printStackTrace(); 
  } finally { 
   if (ftp.isConnected()) { 
    try { 
     ftp.disconnect(); 
    } catch (IOException ioe) { 
    } 
   } 
  } 
  return success; 
 } 

Here are the test cases for file download:

 /** 
  *  will FTP The file on the server is downloaded locally  
  * 
  */ 
 public void testDownFile(){ 
  try { 
   boolean flag = downFile("127.0.0.1", 21, "administrator", "zyuc2011", "test", "test.txt", "D:/"); 
   System.out.println(flag); 
  } catch (Exception e) { 
   e.printStackTrace(); 
  }   
 } 

The above is the entire content of this article, I hope to help you with your study.