在Bluetooth 的傳輸的Protocl上.包括 RFCOMM 和 Object Exchange (OBEX) 兩種方式.底下就protocl 部分做個簡單的介紹
Ref:
http://funningboy.blogspot.com/2010/04/bluetooth-case-study.html
藍芽通訊協定stack
- HCI 主機控制器介面(Host Controller Interface).
主機(電腦)和控制器(藍芽設備)之間的介面.
- L2CAP 邏輯連結控制器適配協定(Logical Link Controller Adaptation Protocol),這一層充當其他所有層的資料多工器.
- BNEP 即藍芽網路封裝協定(Bluetooth Network Encapsulation Protocol) , 可以在藍芽上執行其他網路協定, 例如 IP、TCP 和 UDP.
- RFCOMM 稱作虛擬串流通訊協定(virtual serial port protocol),因為它允許藍芽設備類比串流的功能
- OBEX 通訊協定層是在 RFCOMM 層上面實作, 把資料以物件 "檔" (data) 的形式傳輸
- SDP 是服務發現協定(Service Discovery Protocol)層,用於在遠端藍芽設備上尋找服務
- AVCTP 和 AVDTP,用於藍芽上音頻和視頻的控制.
底下用 jsr82 來實現 RFCOMM.
Server.java
import java.io.*;
import javax.microedition.io.*;
import javax.bluetooth.*;
public class RFCOMMServer {
public static void main( String args[] ) {
try {
String url = "btspp://localhost:" +
new UUID( 0x1101 ).toString() +
";name=SampleServer";
StreamConnectionNotifier service =
(StreamConnectionNotifier) Connector.open( url );
StreamConnection con =
(StreamConnection) service.acceptAndOpen();
OutputStream os = con.openOutputStream();
InputStream is = con.openInputStream();
String greeting = "JSR-82 RFCOMM server says hello";
os.write( greeting.getBytes() );
byte buffer[] = new byte[80];
int bytes_read = is.read( buffer );
String received = new String(buffer, 0, bytes_read);
System.out.println("received: " + received);
con.close();
} catch ( IOException e ) {
System.err.print(e.toString());
}
}
}
Client.java
import java.io.*;
import javax.microedition.io.*;
import javax.bluetooth.*;
public class RFCOMMClient {
public static void main( String args[] ) {
try {
String url = "btspp://0123456789AB:3";
StreamConnection con =
(StreamConnection) Connector.open(url);
OutputStream os = con.openOutputStream();
InputStream is = con.openInputStream();
String greeting = "JSR-82 RFCOMM client says hello";
os.write( greeting.getBytes() );
byte buffer[] = new byte[80];
int bytes_read = is.read( buffer );
String received = new String(buffer, 0, bytes_read);
System.out.println("received: " + received);
con.close();
} catch ( IOException e ) {
System.err.print(e.toString());
}
}
}
請注意 "url" 要改成你的 address & port.
如不知道,可用jsr 82所提供的 ServiceSearch.java
Ref: http://www.jsr82.com/
結果:
BlueCove version 2.1.0 on winsock
wait for device inquiry to complete...
Device 001D289E7AFE found
name K530i
Device 2421AB354DC5 found
Device 001E45B4779B found
name Z610i
Device Inquiry completed!
3 device(s) found
BlueCove stack shutdown completed
Target: GPS application
Design Flow:
1. 利用 J2ME Wireless Toolkit (JSR179),取得經緯度位置,
La = get Latitude(); //取得緯度
Ln = get Longitude(); //取得經度
2.在用Html request的方式透過http://tinygeocoder.com/create-api.php?g=”+lat+”,”+lon,取得我們易懂的位置.
La = 33.790348
Ln = 117.226085
example:
http://tinygeocoder.com/create-api.php?g=33.790348,-117.226085
3. 最後可以結合
Google Map Display.
Flow Chart
Sample Code: Get La,Ln
