Java connection ftp server and for file uploads and downloads

① create client 

 FTPClient  ftpClient= new FTPClient();

② client connections landing ftp server

ftpClient.connect (hostname, port); // ftp server connection

ftpClient.login (username, password); // Log in ftp server

③ determine whether the successful landing

int replyCode = ftpClient.getReplyCode (); // replyCode represents the status code is returned.

FTPReply.isPositiveCompletion (replyCode) // status determination status code, if true, indicates that the connection is successful.

④ after the connection operation

A, ftpClient upload files

 ftpClient.setFileType (ftpClient.BINARY_FILE_TYPE) // output in binary form

ftpClient.makeDirectory (pathname) after // ftp download file save path

ftpClient.changeWorkingDirectory (pathname) // Switch to the file path

ftpClient.storeFile (fileName, inputStream) // start the download, inputStream represents the data source.

Two: ftpClient download file

ftpClient.changeWorkingDirectory (pathname); // into the working directory

ftpClient.retrieveFile (file.getName (), os); // need to download the file name names, os is BufferReader data origins.

Three: ftpClient delete files

ftpClient.changeWorkingDirectory(pathname)；

ftpClient.dele (filename); // delete the corresponding files

⑤ close the connection

ftpClient.loginout ();

ftpClient.disconnected();