Java - 将串口字节数组转换为Int？

Question

我正在尝试在我的 java 界面中制作应变计显示数字。

我让应变计电路工作，它将其电压发送到微 Controller (PIC16F877A) 程序以进行模数转换，然后在串行端口上输出数字。如果你有兴趣，这里是代码:

unsigned short analog;            //Variable for analog voltage
long tlong;
unsigned char ch;                    //

void main() {
  USART_Init(19200);              //set baude rate

  ADCON1 = 0;                     //All PORTA pins as analog, VDD as Vref
  TRISA  = 0xFF;                  //All PORTA is input

  do {
    analog = ADC_Read(2) >> 2;    //Read 10-bit ADC from AN2 and discard 2 LS bit

    tlong = (long)analog * 5000;  // Convert the result in millivolts
    tlong = tlong / 1023;         // 0..1023 -> 0-5000mV
    ch = tlong / 1000;            // Extract volts (thousands of millivolts) from result

    USART_Write(48+ch);           // Write result in ASCII format
    USART_Write('.');

    ch = (tlong / 100) % 10;      // Extract hundreds of millivolts
    USART_Write(48+ch);           // Write result in ASCII format

    ch = (tlong / 10) % 10;       // Extract tens of millivolts
    USART_Write(48+ch);           // Write result in ASCII format

    ch = tlong % 10;              // Extract digits for millivolts
    USART_Write(48+ch);           // Write result in ASCII format
    USART_Write(' ');
    USART_Write(' ');
    USART_Write(' ');

    Delay_ms(1000);
  } while (1);
}

这并不完美，因为当我移动应变计时，输出数字不会改变它们应该的方式。如果有人对此有任何想法，将不胜感激。

但我还是继续前进并将这些数字发送到我的 java 程序中。我在网上找到了这个并对其进行了修改以适合我的设计:

import java.io.*;
import java.util.*; 
import gnu.io.*;


public class SimpleRead implements Runnable, SerialPortEventListener {
    static CommPortIdentifier portId;
    static Enumeration portList;

InputStream inputStream;
SerialPort serialPort;
Thread readThread;
static byte[] readBuffer;
public static int result2;

public static void main(String[] args) {
    portList = CommPortIdentifier.getPortIdentifiers();
    System.out.println("portList... " + portList);

    while (portList.hasMoreElements()) {
        portId = (CommPortIdentifier) portList.nextElement();
        if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
            System.out.println("port identified is Serial.. "
                    + portId.getPortType());
            if (portId.getName().equals("COM4")) {
                System.out.println("port identified is COM4.. "
                        + portId.getName());
                // if (portId.getName().equals("/dev/term/a")) {
                SimpleRead reader = new SimpleRead();
            } else {
                System.out.println("unable to open port");
            }
        }
    }
}

public SimpleRead() {
    try {
        System.out.println("In SimpleRead() contructor");
        serialPort = (SerialPort) portId.open("SimpleReadApp1111",500);
        System.out.println(" Serial Port.. " + serialPort);
    } catch (PortInUseException e) {
        System.out.println("Port in use Exception");
    }
    try {
        inputStream = serialPort.getInputStream();
        System.out.println(" Input Stream... " + inputStream);
    } catch (IOException e) {
        System.out.println("IO Exception");
    }
    try {
        serialPort.addEventListener(this);

    } catch (TooManyListenersException e) {
        System.out.println("Tooo many Listener exception");
    }
    serialPort.notifyOnDataAvailable(true);
    try {

        serialPort.setSerialPortParams(19200, SerialPort.DATABITS_8,
                SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);

        // no handshaking or other flow control
        serialPort.setFlowControlMode(SerialPort.FLOWCONTROL_NONE);

        // timer on any read of the serial port
        serialPort.enableReceiveTimeout(500);

        System.out.println("................");

    } catch (UnsupportedCommOperationException e) {
        System.out.println("UnSupported comm operation");
    }
    readThread = new Thread(this);
    readThread.start();
}

public void run() {
    try {
        System.out.println("In run() function ");
        Thread.sleep(500);
        // System.out.println();
    } catch (InterruptedException e) {
        System.out.println("Interrupted Exception in run() method");
    }
}

public void serialEvent(SerialPortEvent event) {

    // System.out.println("In Serial Event function().. " + event +
    // event.getEventType());
    switch (event.getEventType()) {
    /*
     * case SerialPortEvent.BI: case SerialPortEvent.OE: case
     * SerialPortEvent.FE: case SerialPortEvent.PE: case SerialPortEvent.CD:
     * case SerialPortEvent.CTS: case SerialPortEvent.DSR: case
     * SerialPortEvent.RI: case SerialPortEvent.OUTPUT_BUFFER_EMPTY: break;
     */
    case SerialPortEvent.DATA_AVAILABLE:
        readBuffer = new byte[500];

        try {

            while (inputStream.available()>0) {

                int numBytes = inputStream.read(readBuffer);

            //   System.out.println("Number of bytes read " + numBytes);
                System.out.print(new String(readBuffer));
            }



        } catch (IOException e) {
            System.out.println("IO Exception in SerialEvent()");
        }
        break;
    }
    // System.out.println();
/*  String one = new String(readBuffer);
    char two = one.charAt(0);
    System.out.println("Character at three: " + two);*/
}

}

它读取与之前代码相同范围的数字(一个串行端口，所以我无法测试它是否是相同的数字)，尽管它有时会给我一些奇怪的数字，而不是 .692，它会说 320 ，那么下一个数字是 43，那么可能只有一个 '.'会出现，但很快就会恢复正常。我认为这是一个缓冲区问题，上面写着“readBuffer = new byte[500]”，我将大小更改为 500(最初是 8)，结果稍微好一些。

无论如何，我必须将输出转换为整数才能对其进行一些数学运算，并且作为整数，我可以轻松过滤掉所有奇怪的数据。所以最终，我的问题是现在我是否会将此输出数据转换为可用的整数？主要问题是我什至不确定它在我的 java 程序中的哪个位置读取串行端口号。我假设该变量是 readBuffer，但每当我尝试使用它时都会出错，通常是类型不匹配。

所以任何帮助都会很棒，谢谢!

Answer 1

我进一步研究了你上面的代码，我认为上面代码中的流是:

<x.xxx > ，所以如果您每次读取 8 个字节，那将是一个数据条目。如果您使用 inputstreamreader，如果将字节转换为字符...

检查 http://docs.oracle.com/javase/1.4.2/docs/api/java/io/InputStreamReader.html