如何编写 Java 代码，将一行字符串返回到 Arduino 的字符串变量中？

Question

如何使下面的串行发送和接收（RX/TX）代码像缓冲区一样工作，直到将特定字节设置为缓冲区，直到在

http://processing.org/reference/libraries/serial/Serial_bufferUntil_.html

等 inString = (myPort.readString());

import gnu.io.CommPort;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * This version of the TwoWaySerialComm example makes use of the
 * SerialPortEventListener to avoid polling.
 *
 */
public class TwoWaySerialComm
{
    public TwoWaySerialComm()
    {
        super();
    }

    void connect ( String portName ) throws Exception
    {
        CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(portName);
        if ( portIdentifier.isCurrentlyOwned() )
        {
            System.out.println("Error: Port is currently in use");
        }
        else
        {
            CommPort commPort = portIdentifier.open(this.getClass().getName(),2000);

            if ( commPort instanceof SerialPort )
            {
                SerialPort serialPort = (SerialPort) commPort;
                serialPort.setSerialPortParams(
                  57600,
                  SerialPort.DATABITS_8,
                  SerialPort.STOPBITS_1,
                  SerialPort.PARITY_NONE);

                InputStream in = serialPort.getInputStream();
                OutputStream out = serialPort.getOutputStream();

                (new Thread(new SerialWriter(out))).start();

                serialPort.addEventListener(new SerialReader(in));
                serialPort.notifyOnDataAvailable(true);
            }
            else
            {
                System.out.println("Error: Only serial ports are handled by this example.");
            }
        }
    }

    /**
     * Handles the input coming from the serial port. A new line character
     * is treated as the end of a block in this example.
     */
    public static class SerialReader implements SerialPortEventListener
    {
        private InputStream in;
        private byte[] buffer = new byte[1024];

        public SerialReader ( InputStream in )
        {
            this.in = in;
        }

        public void serialEvent(SerialPortEvent arg0) {
            int data;

            try
            {
                int len = 0;
                while ( ( data = in.read()) > -1 )
                {
                    if ( data == '\n' ) {
                        break;
                    }
                    buffer[len++] = (byte) data;
                }
                System.out.print(new String(buffer,0,len));
            }
            catch ( IOException e )
            {
                e.printStackTrace();
                System.exit(-1);
            }
        }
    }

    /** */
    public static class SerialWriter implements Runnable
    {
        OutputStream out;

        public SerialWriter ( OutputStream out )
        {
            this.out = out;
        }

        public void run ()
        {
            try
            {
                int c = 0;
                while ( ( c = System.in.read()) > -1 )
                {
                    this.out.write(c);
                }
            }
            catch ( IOException e )
            {
                e.printStackTrace();
                System.exit(-1);
            }
        }
    }


    public static void main ( String[] args )
    {
        try
        {
            (new TwoWaySerialComm()).connect("COM3");
        }
        catch ( Exception e )
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Answer 1

解决了....

package smartOfficeJava;

import gnu.io.CommPort;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * This version of the TwoWaySerialComm example makes use of the 
 * SerialPortEventListener to avoid polling.
 *
 */
public class Arduino
{
    OutputStream out;
    SerialReader input;
    public Arduino()
    {
        super();
    }

    void connect ( String portName ) throws Exception
    {
        CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(portName);
        if ( portIdentifier.isCurrentlyOwned() )
        {
            System.out.println("Error: Port is currently in use");
        }
        else
        {
            CommPort commPort = portIdentifier.open(this.getClass().getName(),2000);

            if ( commPort instanceof SerialPort )
            {
                SerialPort serialPort = (SerialPort) commPort;
                serialPort.setSerialPortParams(9600,SerialPort.DATABITS_8,SerialPort.STOPBITS_1,SerialPort.PARITY_NONE);

                InputStream in = serialPort.getInputStream();
                out = serialPort.getOutputStream();

                //(new Thread(new SerialWriter(out))).start();
                input = new SerialReader(in);
                serialPort.addEventListener(input);
                serialPort.notifyOnDataAvailable(true);
                Thread.sleep(3000);
                out.write("yes".getBytes());   

            }
            else
            {
                System.out.println("Error: Only serial ports are handled by this example.");
            }
        }     
    }

    /**
     * Handles the input coming from the serial port. A new line character
     * is treated as the end of a block in this example. 
     */
    public static class SerialReader implements SerialPortEventListener 
    {
        private InputStream in;
        private byte[] buffer = new byte[1024];
        String buffer_string;
        public SerialReader ( InputStream in )
        {
            this.in = in;
        }

        public void serialEvent(SerialPortEvent arg0) {
            int data;

            try
            {
                int len = 0;
                while ( ( data = in.read()) > -1 )
                {
                    if ( data == '\n' ) {
                        break;
                    }
                    buffer[len++] = (byte) data;
                }
                //System.out.print(new String(buffer,0,len));
                buffer_string = new String(buffer,0,len);
            }
            catch ( IOException e )
            {
                e.printStackTrace();
                System.exit(-1);
            }             
        }

    }

    /** 
    public static class SerialWriter implements Runnable 
    {
        OutputStream out;

        public SerialWriter ( OutputStream out )
        {
            this.out = out;
        }

        public void run ()
        {
            try
            {                
                int c = 0;
                while ( ( c = System.in.read()) > -1 )
                {
                    this.out.write(c);
                }                
            }
            catch ( IOException e )
            {
                e.printStackTrace();
                System.exit(-1);
            }            
        }
    }*/

   public String getSensor(){
       try
       {                
               this.out.write("yes".getBytes());              
       }
       catch ( IOException e )
       {
           e.printStackTrace();
       }  
       try {
        Thread.sleep(3000);
    } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
       return (input.buffer_string).trim();

   }

    public static void main ( String[] args )
    {
        Arduino test;
        try
        {
            test = new Arduino();
            test.connect("COM3");
            System.out.println(test.getSensor());
            System.out.println(test.getSensor());
            System.out.println(test.getSensor());
        }
        catch ( Exception e )
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }


}

Answer 2

    import gnu.io.CommPort;
    import gnu.io.CommPortIdentifier;
    import gnu.io.SerialPort;

    import java.io.InputStream;
    import java.io.OutputStream;

    public class SerialComm
    {
    OutputStream out;

    InputStream in;
    public SerialComm()
    {
        super();
    }

    void connect ( String portName ) throws Exception
    {
        CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(portName);
        if ( portIdentifier.isCurrentlyOwned() )
        {
            System.out.println("Error: Port is currently in use");
        }
        else
        {
            CommPort commPort = portIdentifier.open(this.getClass().getName(),2000);

            if ( commPort instanceof SerialPort )
            {
                SerialPort serialPort = (SerialPort) commPort;
                serialPort.setSerialPortParams(9600,SerialPort.DATABITS_8,SerialPort.STOPBITS_1,SerialPort.PARITY_NONE);
                serialPort.setFlowControlMode(SerialPort.FLOWCONTROL_NONE);

                out=serialPort.getOutputStream();

                byte[] Data=hexStringToByteArray("010403e80001b1ba");
                out.write(Data, 0, Data.length);

                Thread.sleep(500);


                in=serialPort.getInputStream();

                byte[] readbuff=new byte[1024];
                int num=0;
                while(in.available()>0)
                {
                    num=in.read(readbuff);
                }

                System.out.println(ByteToHex(readbuff,num));

            }
            else
            {
                System.out.println("Error: Only serial ports are handled by this example.");
            }
        }     
    }



    public String ByteToHex(byte[] b,int len) throws Exception
    {

        String result="";

        for (int i=0;i<len;i++)
        {
            result+=Integer.toString((b[i]& 0xff)+0x100, 16).substring(1);
        }
        return result;
    }



    public byte[] hexStringToByteArray(String s) {
        int len = s.length();
        byte[] data = new byte[len / 2];
        for (int i = 0; i < len; i += 2) {
            data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)+ Character.digit(s.charAt(i+1), 16));
        }
        return data;
    }



    public static void main ( String[] args )
    {
        SerialComm test;
        try
        {
            test = new SerialComm();
            test.connect("/dev/ttyUSB0");

        }
        catch ( Exception e )
        {

            e.printStackTrace();
        }
    }
}