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Transfer raw binary with apache commons-net FTPClient?

Asked 2010-06-30T00:41:26.320
27

UPDATE: Solved

I was calling FTPClient.setFileType() before I logged in, causing the FTP server to use the default mode (ASCII) no matter what I set it to. The client, on the other hand, was behaving as though the file type had been properly set. BINARY mode is now working exactly as desired, transporting the file byte-for-byte in all cases. All I had to do was a little traffic sniffing in wireshark and then mimicing the FTP commands using netcat to see what was going on. Why didn't I think of that two days ago!? Thanks, everyone for your help!

I have an xml file, utf-16 encoded, which I am downloading from an FTP site using apache's commons-net-2.0 java library's FTPClient. It offers support for two transfer modes: ASCII_FILE_TYPE and BINARY_FILE_TYPE, the difference being that ASCII will replace line separators with the appropriate local line separator ('\r\n' or just '\n' -- in hex, 0x0d0a or just 0x0a). My problem is this: I have a test file, utf-16 encoded, that contains the following:

<?xml version='1.0' encoding='utf-16'?>
<data>
    <blah>blah</blah>
</data>

Here's the hex:
0000000: 003c 003f 0078 006d 006c 0020 0076 0065 .<.?.x.m.l. .v.e
0000010: 0072 0073 0069 006f 006e 003d 0027 0031 .r.s.i.o.n.=.'.1
0000020: 002e 0030 0027 0020 0065 006e 0063 006f ...0.'. .e.n.c.o
0000030: 0064 0069 006e 0067 003d 0027 0075 0074 .d.i.n.g.=.'.u.t
0000040: 0066 002d 0031 0036 0027 003f 003e 000a .f.-.1.6.'.?.>..
0000050: 003c 0064 0061 0074 0061 003e 000a 0009 .<.d.a.t.a.>....
0000060: 003c 0062 006c 0061 006

java ftp binary-data apache-commons-net
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I found that Apache retrieveFile(...) sometimes did not work with File Sizes exceeding a certain limit. To overcome that I would used retrieveFileStream() instead. Prior to download I have set the Correct FileType and set the Mode to PassiveMode

So the code will look like

    ....
    ftpClientConnection.setFileType(FTP.BINARY_FILE_TYPE);
    ftpClientConnection.enterLocalPassiveMode();
    ftpClientConnection.setAutodetectUTF8(true);

    //Create an InputStream to the File Data and use FileOutputStream to write it
    InputStream inputStream = ftpClientConnection.retrieveFileStream(ftpFile.getName());
    FileOutputStream fileOutputStream = new FileOutputStream(directoryName + "/" + ftpFile.getName());
    //Using org.apache.commons.io.IOUtils
    IOUtils.copy(inputStream, fileOutputStream);
    fileOutputStream.flush();
    IOUtils.closeQuietly(fileOutputStream);
    IOUtils.closeQuietly(inputStream);
    boolean commandOK = ftpClientConnection.completePendingCommand();
    ....
answered 2013-05-15T12:57:38.833

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