- Java ftp client download file example how to#
- Java ftp client download file example code#
Java ftp client download file example how to#
* A program demonstrates how to upload files from local computer to a remote Here is the program’s source code: import java.io.BufferedOutputStream In the following sample program, using both methods is implemented for transferring a file from the FTP server to local computer.
Java ftp client download file example code#
Java FTP File Download Sample program code Check return value of completePendingCommand() to verify success.ģ.Close the opened OutputStream the InputStream.Call completePendingCommand() method to complete transaction.
Repeatedly a byte array from the InputStream and write these bytes into the OutputStream, until the InputStream is empty. Retrieve an InputStream returned by the method retrieveFileStream(). If using the second method ( retrieveFileStream):. Check return value of retrieveFile() to verify success. Pass the remote file path and the OutputStream as arguments of the method retrieveFile(). If using the first method ( retrieveFile):. Create a new OutputStream for writing the file to disk. Construct path of the remote file to be downloaded. Set file type to be transferred to binary. Enter local passive mode for data connection. The proper steps to download a file Here are the steps to properly implement code for downloading a remote file from a FTP server using Apache Commons Net API which is discussed so far: It is recommended to set file type to FTP.BINARY_FILE_TYPE, rather than FTP.ASCII_FILE_TYPE.Ģ. boolean setFileType(int fileType) : this method sets file type to be transferred, either as ASCII text file or binary file. 
There might be some connection issues if this method is not invoked.
void enterLocalPassiveMode(): this method switches data connection mode from server-to-client (default mode) to client-to-server which can pass through firewall. In addition, the following two methods must be invoked before calling the retrieveFile() and retrieveFileStream() methods: Therefore, make sure to handle these exceptions when calling the methods. Both the methods throw an IOException exception (or one of its descendants, FTPConnectionClosedException and CopyStreamException). In addition, we have to call the completePendingCommand()to finalize the download. how many percentages of the file have been transferred. This method is useful when we want to measure progress of the download, i.e. The second method requires more code to be written, as we have to create a new OutputStream for writing file’s content while reading its byte arrays from the returned InputStream. The first method provides the simplest way for downloading a remote file, as just passing an OutputStream of the file will be written on disk. Which method is used suitable for you? Here are few tips: We must close the InputStream explicitly. The method completePendingCommand() must be called afterward to finalize file transfer and check its return value to verify if the download is actually done successfully. 
But there are two important points when using this method: This method gives us more control on how to read and write the data.
InputStream retrieveFileStream(String remote): This method does not use an OutputStream, instead it returns an InputStreamwhich we can use to read bytes from the remote file. We should close OutputStream the after the method returns. This method is suitable in case we don’t care how the file is written to disk, just let the system use the given OutputStream to write the file. 
The method returns true if operation completed successfully, or false otherwise. boolean retrieveFile(String remote, OutputStream local): This method retrieves a remote file whose path is specified by the parameter remote, and writes it to the OutputStream specified by the parameter local.Apache Commons Net API for downloading files by FTP protocol The .ftp.FTPClient class provides two methods for downloading files from a FTP server: Apache Commons Net API for downloading files by FTP protocolġ.In this article, you will learn how to properly implement Java code to get files downloaded from a server via FTP protocol. With the help of Apache Commons Net API, it is easy to write Java code for downloading a file from a remote FTP server to local computer.
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