Question

我想在JAVA中编写一个简单的服务器和客户端，通过蓝牙交换字符串（我想从笔记本电脑A发送字符串到笔记本电脑B，它们都有Windows 7 64位）。经过一些谷歌搜索，我找到了bluecove java库。基于示例here

我为我的服务器编写了这段代码并且运行时遇到问题，但我遇到了客户端问题。当我想运行客户端时，我收到此错误

在winsock上的BlueCove版本2.1.1-SNAPSHOT java.lang.ClassCastException：com.intel.bluetooth.BluetoothRFCommConnectionNotifier无法强制转换为javax.microedition.io.StreamConnection 在bluetooch.Main.main（Main.java:84）

这是我的服务器：

package MainPackage;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import javax.bluetooth.*;
import javax.microedition.io.*;

//Class that implements an SPP Server which accepts single line of
// message from an SPP client and sends a single line of response to the  
//client

public class BluetoothServer {

//start server
private void startServer() throws IOException{

    //Create a UUID for SPP
    UUID uuid = new UUID("1101", true);
    //Create the servicve url
    String connectionString = "btspp://localhost:" + uuid +";name=Sample SPP       Server";

    //open server url
   StreamConnectionNotifier streamConnNotifier = (StreamConnectionNotifier)Connector.open( connectionString );

    //Wait for client connection
    System.out.println("\nServer Started. Waiting for clients to connect...");
    StreamConnection connection = streamConnNotifier.acceptAndOpen();

    RemoteDevice dev = RemoteDevice.getRemoteDevice(connection);
    System.out.println("Remote device address: "+dev.getBluetoothAddress());
    System.out.println("Remote device name: "+dev.getFriendlyName(true));

    //read string from spp client
    InputStream inStream=connection.openInputStream();
    BufferedReader bReader=new BufferedReader(new InputStreamReader(inStream));
    String lineRead=bReader.readLine();
    System.out.println(lineRead);

    //send response to spp client
    OutputStream outStream=connection.openOutputStream();
    PrintWriter pWriter=new PrintWriter(new OutputStreamWriter(outStream));
    pWriter.write("Response String from SPP Server\r\n");
    pWriter.flush();
    pWriter.close();
    streamConnNotifier.close();
}


public static void main(String[] args) {

    try {
        //display local device address and name
        LocalDevice localDevice = LocalDevice.getLocalDevice();
        System.out.println("Address: "+localDevice.getBluetoothAddress());
        System.out.println("Name: "+localDevice.getFriendlyName());
        System.out.println("localDevice.getDiscoverable() " + localDevice.getDiscoverable());

        System.out.println("bluetooth is discoverable " + localDevice.setDiscoverable(DiscoveryAgent.LIAC));
        BluetoothServer sampleSPPServer=new BluetoothServer();
        sampleSPPServer.startServer();

    } catch (Exception e) {

        e.printStackTrace();
    } 

}

}

这是客户端

package bluetooch;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.Scanner;
import java.util.Vector;
import javax.microedition.io.Connector;
import javax.microedition.io.StreamConnection;

public class Main {

public static final Vector devicesDiscovered = new Vector();
public static void main(String[] args){

    try {            


            StreamConnection streamConnection =        (StreamConnection)Connector.open("btspp://localhost:" + "1101" +";name=Sample  SPP Server");      
            //send string
            OutputStream outStream = streamConnection.openOutputStream();
            PrintWriter pWriter=new PrintWriter(new OutputStreamWriter(outStream));
            pWriter.write("Test String from SPP Client\r\n");
            pWriter.flush();

            //read response
            InputStream inStream=streamConnection.openInputStream();
            BufferedReader bReader2=new BufferedReader(new InputStreamReader(inStream));
            String lineRead=bReader2.readLine();
            System.out.println(lineRead);



        Scanner keyboard = new Scanner(System.in);
        System.out.println("enter an integer");
        int myint = keyboard.nextInt();

    } catch (Exception e) {
        System.out.println("Error Occured! below is the message\r\n" + e.getMessage());
    }
}

}

关于这个问题的任何想法？

Answer 1

嗯，消息说明了一切。

您正在将Connection返回的Connector.open()投射到StreamConnection。

但是返回的连接不是StreamConnection的实例。它是com.intel.bluetooth.BluetoothRFCommConnectionNotifier的一个实例，如果您阅读了javadoc或源代码，则会实现StreamConnectionNotifier，而不是StreamConnection。

java

1 个答案: