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This article describes how to use the Bluetooth File Transfer profile (FTP) with Java on a
desktop computer. More precisely it shows the code needed to browse a mobile
phone folders, create new folders to get or store a new file one the mobile
phone. In order this to be achieved a Bluetooth stack needs to be installed that
is compatible with JSR 82 and it has support for OBEX. In my case I have used
avetana Bluetooth Stuck. Avetana is a Bluetooth stuck that is compatible with
JSR 82 and it has support for OBEX, moreover it offers a free version for Linux.
The code has been tested on a Nokia 6230i mobile phone.
File Transfer is based on OBEX profile. Both specifications can be
found in bluetooth.org (free registration is required). The CONNECT, PUT, GET,
SETPATH and DISCONNECT methods are being used with the appropriate headers.
In all cases initially a connection to the remote device must be established, a
ClientSession class has to be created and its connect method should be used by
setting the TARGET field of its header to the UUID of the Folder Browsing UUID
which is always F9EC7BC4-953C-11D2-984E-525400DC9E09. Then for each case -
browse a folder, read a file, write a file - different actions should be taken
In order to browse the folders that exist in our mobile phone, the following
steps should be followed:
- Connect to the phone
- Go the folder whose contents we want to browse by using SETPATH
- Retrieve the contents of the folder by using the GET method by setting
the TYPE field of the header to "x-obex/folder-listing". The result will be
an XML file
The following code demonstrates how to browse the contents of a folder in a
mobile phone memory:
try{
String btURL = "btgoep://0013FD94B84F:10;authenticate=false;encrypt=false;master=false";
//The above is the url of the OBEX File Transfer service
where:
//0013FD94B84F = the Bluetooth address of the device
//10 = the channel of the service
String folder = "Nikos";
//The above is the name of the folder which we want to browse
//if set to "" it shows the contents of the root folder
ClientSession conn = (ClientSession) Connector.open(btURL);
//Target Header must be set to the Folder Browsing UUID:
//F9EC7BC4-953C-11D2-984E-525400DC9E09.
byte[] FBUiid = {(byte)0xF9,(byte)0xEC,(byte)0x7B,(byte)0xC4,(byte)0x95,(byte)0x3C,(byte)0x11,(byte)0xD2,
(byte)0x98,(byte)0x4E,(byte)0x52,(byte)0x54,(byte)0x00,(byte)0xDC,(byte)0x9E,(byte)0x09};
//Connect
HeaderSet header = conn.createHeaderSet();
header.setHeader(HeaderSet.TARGET, FBUiid);
HeaderSet response = conn.connect(header);
//Go the desired folder
header = conn.createHeaderSet();
header.setHeader(HeaderSet.NAME, folder);
HeaderSet result = conn.setPath(header, false, false);//if
the third option is set to true
//the folder if not exist it is created
header.setHeader(HeaderSet.NAME, "test");
//open the folder
result = conn.setPath(header, false, true);
//Retreive the contents of the folder
header = conn.createHeaderSet();
header.setHeader(HeaderSet.TYPE, "x-obex/folder-listing");
Operation op = conn.get(header);
BufferedReader br = new BufferedReader(new InputStreamReader(op.openInputStream()));
String line;
String xmlString = "";
while ((line = br.readLine()) != null) {
xmlString = xmlString + line + "\n";
}
br.close();
op.close();
conn.disconnect(conn.createHeaderSet());
conn.close();
System.out.println("Obex XML String:\n" + xmlString);
}catch(Exception e){
System.out.println("Exception " + e.toString());
}
The result will be similar to the below string
<?xml version="1.0"?>
<!DOCTYPE folder-listing SYSTEM "obex-folder-listing.dtd"
[ <!ATTLIST folder mem-type CDATA #IMPLIED> ]>
<folder-listing version="1.0">
<parent-folder />
<file name="A.jpg" size="53530"
modified="20070101T124332" user-perm="RWD"/>
<folder name="test" created="20070331T180602"
user-perm="RWD" mem-type="MMC"/>
<file name="video1.3gp" size="693052"
modified="20070330T211802" user-perm="RWD"/>
<file name="17.jpg" size="35557"
modified="20070218T183626" user-perm="RWD"/>
<file name="video2.3gp" size="709196"
modified="20070330T212214" user-perm="RWD"/>
<file name="video3.3gp" size="694920"
modified="20070330T212600" user-perm="RWD"/>
</folder-listing>
In order to read a file stored in our mobile phone and store it in our
local disk, the following steps should be followed:
- Connect to the phone
- Go the folder where the file located by using SETPATH
- Retrieve the file by using the GET method by setting the NAME filed of
the header to the file name
try{
String btURL = "btgoep://0013FD94B84F:10;authenticate=false;encrypt=false;master=false";
//The above is the url of the OBEX File Transfer service
where:
//0013FD94B84F = the Bluetooth address of the device
//10 = the channel of the service
String folder = "Nikos";
//The above is the name of the folder in which the file is
located
//If the file is loated in the root folder "" is used
String file = "17.jpg"; //The name of the file we want to get
ClientSession conn = (ClientSession) Connector.open(btURL);
//Target Header must be set to the Folder Browsing UUID:
//F9EC7BC4-953C-11D2-984E-525400DC9E09.
byte[] FBUiid = {(byte)0xF9,(byte)0xEC,(byte)0x7B,(byte)0xC4,(byte)0x95,(byte)0x3C,(byte)0x11,(byte)0xD2,
(byte)0x98,(byte)0x4E,(byte)0x52,(byte)0x54,(byte)0x00,(byte)0xDC,(byte)0x9E,(byte)0x09};
//Connect
HeaderSet header = conn.createHeaderSet();
header.setHeader(HeaderSet.TARGET, FBUiid);
HeaderSet response = conn.connect(header);
//Go the desired folder
header = conn.createHeaderSet();
header.setHeader(HeaderSet.NAME, folder);
//open the folder
HeaderSet result = conn.setPath(header, false, false);//if
the third option is set to true
//the folder if not exist it is created
//Retreive the file
header = conn.createHeaderSet();
header.setHeader(HeaderSet.NAME, file);
Operation op = conn.get(header);
InputStream is = op.openInputStream();
File f = new File(file);
FileOutputStream fos = new FileOutputStream (f);
byte b[] = new byte[1000];
int len;
while (is.available() > 0 && (len = is.read(b)) > 0) {
fos.write (b, 0, len);
}
fos.close();
is.close();
System.out.println ("File stored in: " + f.getAbsolutePath());
conn.disconnect(conn.createHeaderSet());
conn.close();
}catch(Exception e){
System.out.println("Exception " + e.toString());
}
In order to store file stored in our local disk to our mobile phone, the following steps should be followed:
- Connect to the phone
- Go the folder where we want to store the file
- Store the file by using the PUT method by setting the NAME filed of the
header to the file name
try{
String btURL = "btgoep://0013FD94B84F:10;authenticate=false;encrypt=false;master=false";
//The above is the url of the OBEX File Transfer service
where:
//0013FD94B84F = the Bluetooth address of the device
//10 = the channel of the service
String folder = "Nikos";
//The above is the name of the folder in which the file will
be stored
//if we want to store the file in the root folder "" is used
String file = "/home/nikos/id.jpg";
//The name of the file we
want to store
//Target Header must be set to the Folder Browsing UUID:
//F9EC7BC4-953C-11D2-984E-525400DC9E09.
byte[] FBUiid = {(byte)0xF9,(byte)0xEC,(byte)0x7B,(byte)0xC4,(byte)0x95,(byte)0x3C,(byte)0x11,(byte)0xD2,
(byte)0x98,(byte)0x4E,(byte)0x52,(byte)0x54,(byte)0x00,(byte)0xDC,(byte)0x9E,(byte)0x09};
//Connect
HeaderSet header = conn.createHeaderSet();
header.setHeader(HeaderSet.TARGET, FBUiid);
HeaderSet response = conn.connect(header);
//Go to the desired folder
header = conn.createHeaderSet();
header.setHeader(HeaderSet.NAME,folder);
//open the folder
HeaderSet result = conn.setPath(header, false, false);
//Send the file
File sendFile = new File (file);
header = conn.createHeaderSet();
header.setHeader(HeaderSet.NAME, sendFile.getName());
Operation op = conn.put(header);
OutputStream os = op.openOutputStream();
InputStream is = new FileInputStream (sendFile);
byte[] b = new byte[400];
int r;
while ((r = is.read(b)) > 0) {
os.write(b, 0, r);
}
is.close();
os.close();
op.close();
conn.disconnect(conn.createHeaderSet());
conn.close();
System.out.println("finish sending file");
}catch(Exception e){
System.out.println("Exception " + e.toString());
}
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