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BlueTooth探索系列(五)—J2ME蓝牙实战入门
发表日期:2007-12-23
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BlueTooth探索系列(五)—J2ME蓝牙实战入门
作者Jagie-(cleverpig的好朋友)
版权申明: 转载务必保留以下申明和链接 作者:Jagie 地址:http://www.matrix.org.cn/resource/article/43/43868_BlueTooth.Html 关键字:蓝牙,j2me,jsr82,入门
概述
目前,很多手机已经具备了蓝牙功能。虽然MIDP2.0没有包括蓝牙API,但是JCP定义了JSR82, Java APIs for Bluetooth Wireless Technology (JABWT).这是一个可选API,很多支持MIDP2.0的手机已经实现了,比如Nokia 6600, Nokia 6670,Nokia7610等等。对于一个开发者来说,如果目标平台支持JSR82的话,在制作联网对战类型游戏或者应用的时候,蓝牙是一个相当不错的选择。本文给出了一个最简单的蓝牙应用的J2ME程序,用以帮助开发者快速的掌握JSR82。该程序分别在2台蓝牙设备上安装后,一台设备作为服务端先运行,一台设备作为客户端后运行。在服务端上我们发布了一个服务,该服务的功能是把客户端发过来的字符串转变为大写字符串。客户端起动并搜索到服务端的服务后,我们就可以从客户端的输入框里输入任意的字符串,发送到服务端去,同时观察服务端的反馈结果。
本文并不具体讲述蓝牙的运行机制和JSR82的API结构,关于这些知识点,请参考本文的参考资料一节,这些参考资料会给你一个权威的精确的解释。
实例代码
该程序包括3个java文件。一个是MIDlet,另外2个为服务端GUI和客户端GUI。该程序已经在wtk22模拟器和Nokia 6600,Nokia 6670两款手机上测试通过。
stupidBTmidlet.java
import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.Command; import javax.microedition.lcdui.CommandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.List; import javax.microedition.midlet.MIDlet; import javax.microedition.midlet.MIDletStateChangeException;
/** * @author Jagie * * MIDlet */ public class StupidBTMIDlet extends MIDlet implements CommandListener { List list;
ServerBox sb;
ClientBox cb;
/* * (non-Javadoc) * * @see javax.microedition.midlet.MIDlet#startApp() */ protected void startApp() throws MIDletStateChangeException { list = new List("傻瓜蓝牙入门", List.IMPLICIT); list.append("Client", null); list.append("Server", null); list.setCommandListener(this); Display.getDisplay(this).setCurrent(list);
} /** * debug方法 * @param s 要显示的字串 */
public void showString(String s) { Displayable dp = Display.getDisplay(this).getCurrent(); Alert al = new Alert(null, s, null, AlertType.INFO); al.setTimeout(2000); Display.getDisplay(this).setCurrent(al, dp); } /** * 显示主菜单 * */
public void showMainMenu() { Display.getDisplay(this).setCurrent(list); }
protected void pauseApp() { // TODO Auto-generated method stub
}
public void commandAction(Command com, Displayable disp) { if (com == List.SELECT_COMMAND) { List list = (List) disp; int index = list.getSelectedIndex(); if (index == 1) { if (sb == null) { sb = new ServerBox(this); } sb.setString(null); Display.getDisplay(this).setCurrent(sb); } else { //每次都生成新的客户端实例 cb = null; System.gc(); cb = new ClientBox(this);
Display.getDisplay(this).setCurrent(cb); } } }
protected void destroyApp(boolean arg0) throws MIDletStateChangeException { // TODO Auto-generated method stub
}
}
clientbox.java
import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.IOException;
import java.util.Vector;
import javax.microedition.io.Connector; import javax.microedition.io.StreamConnection; import javax.microedition.lcdui.Command; import javax.microedition.lcdui.CommandListener; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.lcdui.Gauge; import javax.microedition.lcdui.StringItem; import javax.microedition.lcdui.TextField;
//jsr082 API import javax.bluetooth.BluetoothStateException;
import javax.bluetooth.DeviceClass; import javax.bluetooth.DiscoveryAgent; import javax.bluetooth.DiscoveryListener; import javax.bluetooth.LocalDevice; import javax.bluetooth.RemoteDevice; import javax.bluetooth.ServiceRecord; import javax.bluetooth.UUID;
/** * 客户端GUI * @author Jagie * * TODO To change the template for this generated type comment go to * Window - Preferences - Java - Code Style - Code Templates */ public class ClientBox extends Form implements Runnable, CommandListener, DiscoveryListener {
//字串输入框 TextField input = new TextField(null, "", 50, TextField.ANY); //loger StringItem result = new StringItem("结果:", "");
private DiscoveryAgent discoveryAgent;
private UUID[] uuidSet;
//响应服务的UUID private static final UUID ECHO_SERVER_UUID = new UUID( "F0E0D0C0B0A000908070605040302010", false);
//设备集合 Vector devices = new Vector(); //服务集合 Vector records = new Vector(); //服务搜索的事务id集合 int[] transIDs; StupidBTMIDlet midlet;
public ClientBox(StupidBTMIDlet midlet) { super(""); this.midlet=midlet; this.append(result); this.addCommand(new Command("取消",Command.CANCEL,1)); this.setCommandListener(this); new Thread(this).start(); } public void commandAction(Command arg0, Displayable arg1) { if(arg0.getCommandType()==Command.CANCEL){ midlet.showMainMenu(); }else{ //匿名内部Thread,访问远程服务。 Thread fetchThread=new Thread(){ public void run(){ for(int i=0;i<records.size();i++){ ServiceRecord sr=(ServiceRecord)records.elementAt(i); if(AccessService(sr)){ //访问到一个可用的服务即可 break; } } } }; fetchThread.start(); } } private boolean accessService(ServiceRecord sr){ boolean result=false; try { String url = sr.getConnectionURL( ServiceRecord.NOAUTHENTICATE_NOENCRYPT, false); StreamConnection conn = (StreamConnection) Connector.open(url); DataOutputStream dos=conn.openDataOutputStream(); dos.writeUTF(input.getString()); dos.close(); DataInputStream dis=conn.openDataInputStream(); String echo=dis.readUTF(); dis.close(); showInfo("反馈结果是:"+echo); result=true; } catch (IOException e) { } return result; }
public synchronized void run() { //发现设备和服务的过程中,给用户以Gauge Gauge g=new Gauge(null,false,Gauge.INDEFINITE,Gauge.CONTINUOUS_RUNNING); this.append(g); showInfo("蓝牙初始化..."); boolean isBTReady = false;
try {
LocalDevice localDevice = LocalDevice.getLocalDevice(); discoveryAgent = localDevice.getDiscoveryAgent();
isBTReady = true; } catch (Exception e) { e.printStackTrace(); }
if (!isBTReady) { showInfo("蓝牙不可用"); //删除Gauge this.delete(1); return; }
uuidSet = new UUID[2];
//标志我们的响应服务的UUID集合 uuidSet[0] = new UUID(0x1101); uuidSet[1] = ECHO_SERVER_UUID;
try { discoveryAgent.startInquiry(DiscoveryAgent.GIAC, this); } catch (BluetoothStateException e) {
}
try { //阻塞,由inquiryCompleted()回调方法唤醒 wait(); } catch (InterruptedException e1) { e1.printStackTrace(); } showInfo("设备搜索完毕,共找到"+devices.size()+"个设备,开始搜索服务"); transIDs = new int[devices.size()]; for (int i = 0; i < devices.size(); i++) { RemoteDevice rd = (RemoteDevice) devices.elementAt(i); try { //记录每一次服务搜索的事务id transIDs[i] = discoveryAgent.searchServices(null, uuidSet, rd, this); } catch (BluetoothStateException e) { continue; }
} try { //阻塞,由serviceSearchCompleted()回调方法在所有设备都搜索完的情况下唤醒 wait(); } catch (InterruptedException e1) { e1.printStackTrace(); } showInfo("服务搜索完毕,共找到"+records.size()+"个服务,准备发送请求"); if(records.size()>0){ this.append(input); this.addCommand(new Command("发送",Command.OK,0)); } //删除Gauge this.delete(1); } /** * debug * @param s */ private void showInfo(String s){ StringBuffer sb=new StringBuffer(result.getText()); if(sb.length()>0){ sb.append("\n"); } sb.append(s); result.setText(sb.toString());
} /** * 回调方法 */
public void deviceDiscovered(RemoteDevice btDevice, DeviceClass cod) {
if (devices.indexOf(btDevice) == -1) { devices.addElement(btDevice); } }
/** * 回调方法,唤醒初始化线程 */ public void inquiryCompleted(int discType) {
synchronized (this) { notify(); } } /** * 回调方法 */ public void servicesDiscovered(int transID, ServiceRecord[] servRecord) { for (int i = 0; i < servRecord.length; i++) { records.addElement(servRecord[i]); } } /** * 回调方法,唤醒初始化线程 */
public void serviceSearchCompleted(int transID, int respCode) { for (int i = 0; i < transIDs.length; i++) { if (transIDs[i] == transID) { transIDs[i] = -1; break; } } //如果所有的设备都已经搜索服务完毕,则唤醒初始化线程。
boolean finished = true; for (int i = 0; i < transIDs.length; i++) { if (transIDs[i] != -1) { finished = false; break; } }
if (finished) { synchronized (this) { notify(); } }
}
}
serverbox.java
import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.IOException;
import java.util.Vector;
import javax.bluetooth.DiscoveryAgent; import javax.bluetooth.LocalDevice; import javax.bluetooth.ServiceRecord; import javax.bluetooth.UUID; import javax.microedition.io.Connector; import javax.microedition.io.StreamConnection; import javax.microedition.io.StreamConnectionNotifier;
import javax.microedition.lcdui.Command; import javax.microedition.lcdui.CommandListener; import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.TextBox; import javax.microedition.lcdui.TextField;
/** * 服务端GUI * @author Jagie * * TODO To change the template for this generated type comment go to * Window - Preferences - Java - Code Style - Code Templates */ public class ServerBox extends TextBox implements Runnable, CommandListener {
Command com_pub = new Command("开启服务", Command.OK, 0);
Command com_cancel = new Command("终止服务", Command.CANCEL, 0);
Command com_back = new Command("返回", Command.BACK, 1);
LocalDevice localDevice;
StreamConnectionNotifier notifier;
ServiceRecord record;
boolean isClosed;
ClientProcessor processor;
StupidBTMIDlet midlet; //响应服务的uuid private static final UUID ECHO_SERVER_UUID = new UUID( "F0E0D0C0B0A000908070605040302010", false);
public ServerBox(StupidBTMIDlet midlet) { super(null, "", 500, TextField.ANY); this.midlet = midlet; this.addCommand(com_pub); this.addCommand(com_back); this.setCommandListener(this); }
public void run() { boolean isBTReady = false;
try {
localDevice = LocalDevice.getLocalDevice();
if (!localDevice.setDiscoverable(DiscoveryAgent.GIAC)) { showInfo("无法设置设备发现模式"); return; }
// prepare a URL to create a notifier StringBuffer url = new StringBuffer("btspp://");
// indicate this is a server url.append("localhost").append(':');
// add the UUID to identify this service url.append(ECHO_SERVER_UUID.toString());
// add the name for our service url.append(";name=Echo Server");
// request all of the client not to be authorized // some devices fail on authorize=true url.append(";authorize=false");
// create notifier now notifier = (StreamConnectionNotifier) Connector .open(url.toString());
record = localDevice.getRecord(notifier);
// remember we've reached this point. isBTReady = true; } catch (Exception e) { e.printStackTrace(); }
// nothing to do if no bluetooth available if (isBTReady) { showInfo("初始化成功,等待连接"); this.removeCommand(com_pub); this.addCommand(com_cancel); } else { showInfo("初始化失败,退出"); return;
}
// 生成服务端服务线程对象 processor = new ClientProcessor();
// ok, start accepting connections then while (!isClosed) { StreamConnection conn = null;
try { conn = notifier.acceptAndOpen(); } catch (IOException e) { // wrong client or interrupted - continue anyway continue; } processor.addConnection(conn); }
}
public void publish() { isClosed = false; this.setString(null); new Thread(this).start();
}
public void cancelService() { isClosed = true; showInfo("服务终止"); this.removeCommand(com_cancel); this.addCommand(com_pub); }
/* * (non-Javadoc) * * @see javax.microedition.lcdui.CommandListener#commandAction(javax.microedition.lcdui.Command, * javax.microedition.lcdui.Displayable) */ public void commandAction(Command arg0, Displayable arg1) { if (arg0 == com_pub) { //发布service publish(); } else if (arg0 == com_cancel) { cancelService(); } else { cancelService(); midlet.showMainMenu(); }
} /** * 内部类,服务端服务线程。 * @author Jagie * * TODO To change the template for this generated type comment go to * Window - Preferences - Java - Code Style - Code Templates */ private class ClientProcessor implements Runnable { private Thread processorThread;
private Vector queue = new Vector();
private boolean isOk = true;
ClientProcessor() { processorThread = new Thread(this); processorThread.start(); }
public void run() { while (!isClosed) {
synchronized (this) { if (queue.size() == 0) { try { //阻塞,直到有新客户连接 wait(); } catch (InterruptedException e) {
} } } //处理连接队列
StreamConnection conn;
synchronized (this) {
if (isClosed) { return; } conn = (StreamConnection) queue.firstElement(); queue.removeElementAt(0); processConnection(conn); } } } /** * 往连接队列添加新连接,同时唤醒处理线程 * @param conn */
void addConnection(StreamConnection conn) { synchronized (this) { queue.addElement(conn); notify(); } }
}
/** * 从StreamConnection读取输入 * @param conn * @return */ private String readInputString(StreamConnection conn) { String inputString = null;
try {
DataInputStream dis = conn.openDataInputStream(); inputString = dis.readUTF(); dis.close(); } catch (Exception e) { e.printStackTrace(); } return inputString; } /** * debug * @param s */
private void showInfo(String s) { StringBuffer sb = new StringBuffer(this.getString()); if (sb.length() > 0) { sb.append("\n"); }
sb.append(s); this.setString(sb.toString());
}
/** * 处理客户端连接 * @param conn */ private void processConnection(StreamConnection conn) {
// 读取输入 String inputString = readInputString(conn); //生成响应 String outputString = inputString.toUpperCase(); //输出响应 sendOutputData(outputString, conn);
try { conn.close(); } catch (IOException e) { } // ignore showInfo("客户端输入:" + inputString + ",已成功响应!"); } /** * 输出响应 * @param outputData * @param conn */
private void sendOutputData(String outputData, StreamConnection conn) {
try { DataOutputStream dos = conn.openDataOutputStream(); dos.writeUTF(outputData); dos.close(); } catch (IOException e) { }
} }
小结
本文给出了一个简单的蓝牙服务的例子。旨在帮助开发者快速掌握JSR82.如果该文能对你有所启发,那就很好了。进入讨论组讨论。
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