Java讀取串口超時時間

Question

我有一個通過 rxtx 讀取串口的代碼。 但是我希望 input-stream 的 bufferedreader 應該檢查數據是否到來的指定時間。 超時后，它應該停止我開始讀取 serialReader 的程序或線程。

Answer 1

你可以這樣做：

ExecutorService exec = new Executors.newSingleThreadExecutor();

// ... where you want to start reading and wait:
Future<String> readResult = exec.submit( new Callable<String>(){
     @Override public String call(){
          // Your reading code here.
     }
} );

try{
   String strResult = readResult.get( 1, TimeUnit.MINUTES );
} catch(TimeoutException tex) {
    // handle Timeout
} catch ( /*... you should also catch other exceptions like */ IOException ioex ){}

只是初學者的大綱。 讀取操作將在單獨的線程上完成。 然后在主線程上等待它完成，捕獲 TimeoutException。 如果發生，您可以清理您的資源（關閉 COM 端口！！）並退出。 如果沒有發生，則讀取成功。

---

一些資源：

• 執行者
• 執行者服務
• 未來
• 可調用
• Oracle Executors 教程

---

根據您的代碼：

public class SerialReaderWithTimeout implements Runnable {
private final InputStream inputStream;
private final ExecutorService exec = Executors.newSingleThreadExecutor();

public SerialReaderWithTimeout(InputStream in) {
    inputStream = in;

    br = new BufferedReader(new InputStreamReader(inputStream));
    try {
        bw = new BufferedWriter(new FileWriter(FILENAME));
    } catch (IOException e) {
        e.printStackTrace();
    }
}

private String readWithTimeout(){
     String strResult = null;

     Future<String> readResult = exec.submit( new Callable<String>(){
     @Override public String call(){
          return br.readLine();
     }} );

    try{
       strResult = readResult.get( 10, TimeUnit.MINUTES );
    } catch(TimeoutException tex) {
        // handle Timeout: NOP -> Just return null
    } catch ( Exception ex ){
        // handle Exception
        throw;
    }

    return strResult;
}

public void run() {
    String inputLine = null;
    try {

        //while ((inputLine = br.readLine()) != null) {
        while ((inputLine = readWithTimeout()) != null) {
            //series.put(num, inputLine);
             //num++;
            bw.write(inputLine);
            bw.newLine();
            bw.flush();
            System.out.println(inputLine);

            if (inputLine.trim().startsWith("DATE") | inputLine.trim().startsWith("REMARK")
                    | inputLine.trim().startsWith("TESTED BY")) {
                serialPort.close();
                inputStream.close();
                br.close();
                bw.close();
                break;
            }
        }   

        //new CompareClass();
    } catch (IOException e) {
        System.out.println(e.getMessage());
    }
}

請注意，我沒有使用 IDE 來編寫或編譯它，可能有錯別字，需要一些調整。

Answer 2

public ReadWithoutTimings() {
    super();
    num = 1;

    try {


    try {

         serialPort = (SerialPort) portId.open("Read1", 2000);
    } catch (PortInUseException e) {
        System.out.println(e);
        JOptionPane.showMessageDialog(null, e);
    }

    try {
        serialPort.setSerialPortParams(9600, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);

    } catch (UnsupportedCommOperationException e1) {
        System.out.println(e1);
    }
    try {
        in = serialPort.getInputStream();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    /*timer.schedule(new TimerTask() {            
        @Override
          public void run() {

            (new Thread(new SerialReader(in))).start();   
              }

        }, time);*/
    (new Thread(new SerialReader(in))).start();  
}

public class SerialReader implements Runnable {


    public SerialReader(InputStream in) {
        inputStream = in;
        try {
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        br = new BufferedReader(new InputStreamReader(inputStream));
        try {
            bw = new BufferedWriter(new FileWriter(FILENAME));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void run() {
        String inputLine = null;
        try {



            while ((inputLine = br.readLine()) != null) {
                //series.put(num, inputLine);
                 //num++;
                bw.write(inputLine);
                bw.newLine();
                bw.flush();
                System.out.println(inputLine);

                if (inputLine.trim().startsWith("DATE") | inputLine.trim().startsWith("REMARK")
                        | inputLine.trim().startsWith("TESTED BY")) {
                    serialPort.close();
                    inputStream.close();
                    br.close();
                    bw.close();
                    break;
                }
            }   

            //new CompareClass();
        } catch (IOException e) {
            System.out.println(e.getMessage());
        }
    }

Answer 3

可能將 Timer (Schedule) 與您的讀取循環結合使用。

使用如下 -> timer.schedule('your_read_task','time_when_you_want_to_end')