JNI之Java实现蓝牙交互

蓝牙概述

蓝牙，是一种支持设备短距离通信（一般10m内）的无线电技术，能在包括移动电话、PDA、无线耳机、笔记本电脑、相关外设等众多设备之间，通过蓝牙设备之间的无线通信实现数据传输，实现数据传输，音频传输，文件传输，图片传输等多种应用的无线信息交换。利用“蓝牙”技术，能够有效地简化移动通信终端设备之间的通信，也能够成功地简化设备与因特网Internet之间的通信，从而数据传输变得更加迅速高效，为无线通信拓宽道路。蓝牙技术是一种无线数据和语音通信开放的全球规范，它是基于低成本的近距离无线连接，为固定和移动设备建立通信环境的一种特殊的近距离无线技术连接。目前，越来越多的企业采用蓝牙交互技术来实现自己的产品。

Java实现蓝牙交互的优势

Java是世界上最流行的编程语言之一。Java具有平台无关性、对象化编程、简单易用、可扩展性等特点，因此目前已广泛应用于企业和互联网领域。Java还提供了很好的蓝牙接口，可以帮助企业快速开发蓝牙交互应用。Java的蓝牙接口是基于JSR-82标准实现的，这个标准允许JAVA应用程序访问蓝牙网络的API。与其他大多数蓝牙接口不同，JSR-82可以在任意实现了JSR-82标准的蓝牙设备间进行通讯，这就保证了兼容性和灵活性。

蓝牙通信的原理

蓝牙技术规定每一对设备之间进行蓝牙通讯时，必须一个为主角色，另一为从角色，才能进行通信，通信时，必须由主端进行查找，发起配对，建链成功后，双方即可收发数据。

蓝牙主端设备发起呼叫，首先是查找，找出周围处于可被查找的蓝牙设备。主端设备找到从端蓝牙设备后，与从端蓝牙设备进行配对，此时需要输入从端设备的PIN码，也有设备不需要输入PIN码。

配对完成后，从端蓝牙设备会记录主端设备的信任信息，此时主端即可向从端设备发起呼叫，已配对的设备在下次呼叫时，不再需要重新配对。

Java蓝牙交互应用实例

导包

    net.sf.bluecove
    bluecove
    2.1.0

BluetoothServer

public class BluetoothServer implements Runnable {
    //本机蓝牙设备
    private LocalDevice local = null;
    // 流连接
    private StreamConnection streamConnection = null;
    // 输入流
    private InputStream inputStream;
    private OutputStream outputStream;
    //接入通知
    private StreamConnectionNotifier notifier;
    //线程池
    private final static ExecutorService service = Executors.newCachedThreadPool();
    public String serverName;
    public String serverUUID;
    private OnServerListener mServerListener;
    public interface OnServerListener {
        void onConnected(InputStream inputStream, OutputStream outputStream);
        void onDisconnected();
        void onClose();
    }
    public BluetoothServer(String serverUUID, String serverName) {
        this.serverUUID = serverUUID;
        this.serverName = serverName;
    }
    public void start() {
        try {
            local = LocalDevice.getLocalDevice();
            if (!local.setDiscoverable(DiscoveryAgent.GIAC)) {
                System.out.println("请将蓝牙设置为可被发现");
            }
            /**
             * 作为服务端，被请求  ";name="+serverName;
             */
            String url = "btspp://localhost:" +  serverUUID;
            notifier = (StreamConnectionNotifier) Connector.open(url);
            service.submit(this);
        } catch (IOException e) {
            System.out.println(e.getMessage());;
        }
    }

    public OnServerListener getServerListener() {
        return mServerListener;
    }

    public void setServerListener(OnServerListener mServerListener) {
        this.mServerListener = mServerListener;
    }

    @Override
    public void run() {
        try {
            //阻塞的，等待设备连接
            streamConnection = notifier.acceptAndOpen();               
            inputStream = streamConnection.openInputStream();
            outputStream = streamConnection.openOutputStream();

            if (mServerListener != null) {
                mServerListener.onConnected(inputStream, outputStream);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
        }
    }
}

BluetoothClient

public class BluetoothClient {
    private StreamConnection streamConnection;
    private OnDiscoverListener onDiscoverListener = null;
    private OnClientListener onClientListener = null;

    public interface OnClientListener {
        void onConnected(InputStream inputStream, OutputStream outputStream);
        void onConnectionFailed();
        void onDisconnected();
        void onClose();
    }

    public interface OnDiscoverListener {
        void onDiscover(RemoteDevice remoteDevice);
    }
    
    public BluetoothClient() {
    }

    public OnDiscoverListener getOnDiscoverListener() {
        return onDiscoverListener;
    }

    public void setOnDiscoverListener(OnDiscoverListener onDiscoverListener) {
        this.onDiscoverListener = onDiscoverListener;
    }

    public OnClientListener getClientListener() {
        return onClientListener;
    }
    
    public void setClientListener(OnClientListener onClientListener) {
        this.onClientListener = onClientListener;
    }

    public void find() throws IOException, InterruptedException {
        //附近所有的蓝牙设备，必须先执行 runDiscovery
        Set devicesDiscovered = RemoteDeviceDiscovery.getDevices();       
        Iterator itr = devicesDiscovered.iterator();
        //连接
        while (itr.hasNext()) {                                  
            RemoteDevice remoteDevice = itr.next();

            onDiscoverListener.onDiscover(remoteDevice);
        }
    }

    public void startClient(RemoteDevice remoteDevice, String serviceUUID) throws IOException, InterruptedException {
        String url = RemoteDeviceDiscovery.searchService(remoteDevice, serviceUUID);
        streamConnection = (StreamConnection) Connector.open(url);
        if (this.onClientListener != null) {
            this.onClientListener.onConnected(streamConnection.openInputStream(), streamConnection.openOutputStream());
        }
    }
}

RemoteDeviceDiscovery

public class RemoteDeviceDiscovery {
    public final static Set devicesDiscovered = new HashSet();

    public final static Vector serviceFound = new Vector();

    final static Object serviceSearchCompletedEvent = new Object();
    final static Object inquiryCompletedEvent = new Object();
    
    private static DiscoveryListener listener = new DiscoveryListener() {
        public void inquiryCompleted(int discType) {
            System.out.println("#" + "搜索完成");
            synchronized (inquiryCompletedEvent) {
                inquiryCompletedEvent.notifyAll();
            }
        }
        
        @Override
        public void deviceDiscovered(RemoteDevice remoteDevice, DeviceClass deviceClass) {
            devicesDiscovered.add(remoteDevice);

            try {
                System.out.println("#发现设备" + remoteDevice.getFriendlyName(false));
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
        @Override
        public void servicesDiscovered(int transID, ServiceRecord[] servRecord) {
            for (int i = 0; i < servRecord.length; i++) {
                String url = servRecord[i].getConnectionURL(ServiceRecord.NOAUTHENTICATE_NOENCRYPT, false);
                if (url == null) {
                    continue;
                }
                serviceFound.add(url);
                DataElement serviceName = servRecord[i].getAttributeValue(0x0100);
                if (serviceName != null) {
                    System.out.println("service " + serviceName.getValue() + " found " + url);
                } else {
                    System.out.println("service found " + url);
                }
            }
            System.out.println("#" + "servicesDiscovered");
        }

        @Override
        public void serviceSearchCompleted(int arg0, int arg1) {
            System.out.println("#" + "serviceSearchCompleted");
            synchronized(serviceSearchCompletedEvent){
                serviceSearchCompletedEvent.notifyAll();
            }
        }
    };

    private static void findDevices() throws IOException, InterruptedException {
        devicesDiscovered.clear();
        synchronized (inquiryCompletedEvent) {

            LocalDevice ld = LocalDevice.getLocalDevice();
            System.out.println("#本机蓝牙名称:" + ld.getFriendlyName());
            boolean started = LocalDevice.getLocalDevice().getDiscoveryAgent().startInquiry(DiscoveryAgent.GIAC,listener);
            if (started) {
                System.out.println("#" + "等待搜索完成...");
                inquiryCompletedEvent.wait();
                LocalDevice.getLocalDevice().getDiscoveryAgent().cancelInquiry(listener);
                System.out.println("#发现设备数量：" + devicesDiscovered.size());
            }
        }
    }

    public static Set getDevices() throws IOException, InterruptedException {
        findDevices();
        return devicesDiscovered;
    }

    public static String searchService(RemoteDevice btDevice, String serviceUUID) throws IOException, InterruptedException {
        UUID[] searchUuidSet = new UUID[] { new UUID(serviceUUID, false) };

        int[] attrIDs =  new int[] {
                // Service name
                0x0100 
        };

        synchronized(serviceSearchCompletedEvent) {
            System.out.println("search services on " + btDevice.getBluetoothAddress() + " " + btDevice.getFriendlyName(false));
            LocalDevice.getLocalDevice().getDiscoveryAgent().searchServices(attrIDs, searchUuidSet, btDevice, listener);
            serviceSearchCompletedEvent.wait();
        }

        if (serviceFound.size() > 0) {
            return serviceFound.elementAt(0);
        } else {
            return "";
        }
    }
}

测试

Bluetooth Server

@Test
public void test(){
   final String serverName = "Bluetooth Server Test";
   final String serverUUID = "1000110100001000800000805F9B34FB";  //根据需要自定义
   BluetoothServer server = new BluetoothServer(serverUUID, serverName);
   server.setServerListener(new BluetoothServer.OnServerListener() {
       @Override
       public void onConnected(InputStream inputStream, OutputStream outputStream) {
         System.out.printf("Connected");
         //添加通信代码
       }
       @Override
       public void onDisconnected() {

       }
       @Override
       public void onClose() {

       }
    });
    server.start();
}

测试结果

Connected to the target VM, address: '127.0.0.1:8442', transport: 'socket'
Native Library intelbth_x64 not available
Native Library bluecove_x64 not available
BlueCove libraries not available
Disconnected from the target VM, address: '127.0.0.1:8442', transport: 'socket'

没有找到_64的包。

看看导包的版本

下载_64版本

官网：BlueCove - BlueCove JSR-82 project

下载地址：https://sourceforge.net/projects/bluecove/files/

ps：下面自己测试吧。

JNI，Java Native Interface，主要是通过读取其他底层语言的文件，转换成Java的类，操作设备。

另外还有连接打印机、pos机等，也是使用Java的JNI调用其他底层语言的文件，如打印机使用jacob读取dll文件、可实现无接触操作语音智能打印等。