JAVA串口通信的方法
以前经常用C语言操作串口，实现一些发送接收之类的小功能，最近项目中也用到了串口通信，不过语言变成了Java，这个搞起来略蛋疼。
Java说起来就是各种库各种引用，所以得到某些需求先google搜一把~~比如之前搞半天的读取网页内容，自己边琢磨边写，又是charset，又是proxy，又是什么browsertype的，晕头转向，最后拿Jsoup一会儿就搞定了……不过使用之前要充分考虑可扩展性和API的丰富程度，不然后面程序体积变大集成起来很蛋疼。好了废话不说，讲讲串口的问题……
总述
Java常用的（我用到的）串口工具有俩：javacomm和RXTX，前者只支持win32，后者32和64位和其他版本都有。使用方法类似，所以就放到一起说：
下载到压缩包会看到readme之类的提示，然后把对应的dll文件和jar文件分别拷贝到
具体使用过程就是：配置端口波特率、校验位等信息；打开串口；写数据；读输出；关闭。这一系列步骤在写程序的时候一定不要弄颠倒了。
串口配置
需要配置的有4项：
波特率（baudrate）— 一般9600、115200即可
（数据位）dataBits— 一般8 bits
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DATABITS_5: 5 bits
DATABITS_6: 6 bits
DATABITS_7: 7 bits
DATABITS_8: 8 bits
（停止位）stopBits — 一般1 stop bit
-
STOPBITS_1: 1 stop bit
STOPBITS_2: 2 stop bits
STOPBITS_1_5: 1.5 stop bits
（校验位）parity — 不需校验位的话，选择SerialPort.PARITY_NONE
-
PARITY_NONE: no parity
PARITY_ODD: odd parity
PARITY_EVEN: even parity
PARITY_MARK: mark parity
PARITY_SPACE: space parity
流量控制模式(FlowControlMode) — 一般FLOWCONTROL_NONE
-
FLOWCONTROL_NONE: no flow control
FLOWCONTROL_RTSCTS_IN: RTS/CTS (hardware) flow control for input
FLOWCONTROL_RTSCTS_OUT: RTS/CTS (hardware) flow control for output
FLOWCONTROL_XONXOFF_IN: XON/XOFF (software) flow control for input
FLOWCONTROL_XONXOFF_OUT:XON/XOFF (software) flow control for output
事件监听
addEventListener(SerialPortEventListener lsnr)
用于监听串口事件（SerialEvents），可监听的事件有：
BI(Break interrupt)
CD(Carrier detect)
CTS(Clear to send)
DATA_AVAILABLE(Data available at the serial port)
DSR(Data set ready)
eventType(Deprecated. Replaced by getEventType method)
FE(Framing error)
OE(Overrun error)
OUTPUT_BUFFER_EMPTY(Output buffer is empty)
PE(Parity error)
RI(Ring indicator)
读数据
通过SerialPortEventListener来，读取到DATA_AVAILABLE，保存并处理串口内容。
写数据
使用getOutputStream来向串口发送数据，是发送数据的唯一方法。使用时，向OutPutStream中写入byte串即可，之后用SerialPortEventListener获取回馈结果。
RXTX例程（来自 这里 ）：
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public class USBComm implements SerialPortEventListener { public static final String MESSAGE = "MESSAGE TO BE SEND"; /** * Stream for the storage of incoming data */ private InputStream inputStream; /** * Stream for the dispatching of data */ private OutputStream outputStream; /** * Timeout of the USB port */ private final int PORT_TIMEOUT = 2000; /** * Representation of the serial port used for the communication */ public SerialPort serialPort; /** * Buffer that stores the received bytes from the media */ protected LinkedBlockingQueue<Byte> receivedBytes; /** * Builds a new manager for the communication via USB port. * @exception IOException if an error occurred during the opening of the USB port */ public USBComm(String comm) throws IOException { receivedBytes = new LinkedBlockingQueue<Byte>(100000); String port = comm; //place the right COM port here, OS dependent //Check that the USB port exists and is recognized: Enumeration<?> portList = CommPortIdentifier.getPortIdentifiers(); boolean portFound = false; CommPortIdentifier portId = null; while (portList.hasMoreElements()) { portId = (CommPortIdentifier) portList.nextElement(); if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) { if (portId.getName().equals(port)) { Log.logAndDisplay(LogLevel.INFO, "SerialConnection", "Found port: " + port); portFound = true; break; } } } if (!portFound) throw new IOException("port " + port + " not found."); try { Log.logAndDisplay(LogLevel.INFO, "SerialConnection", "USB port " + port + " opening..."); serialPort = (SerialPort) portId.open("USBCommunicator", PORT_TIMEOUT); inputStream = serialPort.getInputStream(); outputStream = serialPort.getOutputStream(); serialPort.addEventListener(this); serialPort.notifyOnDataAvailable(true); Thread.sleep(1000); serialPort.setSerialPortParams(serialPort.getBaudRate(), serialPort.getDataBits(), serialPort.getStopBits(), serialPort.getParity()); serialPort.setFlowControlMode(serialPort.getFlowControlMode()); } catch (Exception e) { System.err.println(e.getMessage()); throw new IOException(e.getMessage()); } } public void closeUSB(){ //close the streams for serial port: try { inputStream.close(); outputStream.close(); } catch (IOException e) { System.err.println("Cannot close streams:" + e.getMessage()); } } /** * Listener for USB events * * @param event new event occurred on the USB port */ public void serialEvent(SerialPortEvent event){ 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: //nothing to do... break; case SerialPortEvent.DATA_AVAILABLE: byte received = -1; do { try { received = (byte)inputStream.read(); } catch (IOException e) { System.err.println("Error reading USB:" + e.getMessage()); } synchronized (receivedBytes) { try { receivedBytes.add(received); } catch (IllegalStateException ew) { System.err.println(ew.getMessage()); receivedBytes.poll(); receivedBytes.add(received); } } } while(received != -1); break; } } public void write(byte[] buffer){ try { outputStream.write(buffer); //outputStream.flush(); } catch (IOException e) { System.err.println("Cannot write:" + e.getMessage()); } } public static void main(String[] args){ USBComm usb; try { usb = new USBComm("COM73"); // change to your port byte[] b = MESSAGE.getBytes(); usb.write(b); usb.serialPort.close(); usb.closeUSB(); } catch (IOException e) { System.err.println("IOException:" + e.getMessage()); } } } |
这个沙发，我表示我一点都看不懂，嘿嘿。
第二发说点啥了，哦，就是java了，今天玩了一下你介绍的飞机游戏，发现这东西怎么做出来了，真是头大。。还是不想了。
不过编程就是从一点点一点点做到最后，让人看起来似乎很复杂，但其实每个功能都有它的一段用处，仔细去做，其实也不难，但它的确让不知道的人摸不着头脑。
写java特别容易写吐。。
哇，哥你C也会啊，高大上啊！
学也不会呢
好奇怪。。
我实在搞不明白，为什么
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