怎么在Java中使用开源Rxtx实现串口通讯？很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。
使用方法：
windows平台：
1、把rxtxParallel.dll、rxtxSerial.dll拷贝到：C:\WINDOWS\system32下。
2、如果是在开发的时候(JDK),需要把RXTXcomm.jar、rxtxParallel.dll、rxtxSerial.dll拷贝到..\jre...\lib\ext下；如：D:\Program Files\Java\jre1.6.0_02\lib\ext
3、而且需要把项目1.右键->2.Preperties(首选项)->3.Java Build Path->4.Libraries->5.展开RXTXcomm.jar->6.Native library location:(None)->7.浏览External Folder(选择至该项目的lib文件夹，如：E:/Item/MyItem/WebRoot/WEB-INF/lib).
import gnu.io.*;
import java.io.*;
import java.util.*;
import com.call.dao.*;
public class SerialReader extends Observable implements Runnable,SerialPortEventListener
{
static CommPortIdentifier portId;
int delayRead = 100;
int numBytes; // buffer中的实际数据字节数
private static byte[] readBuffer = new byte[1024]; // 4k的buffer空间,缓存串口读入的数据
static Enumeration portList;
InputStream inputStream;
OutputStream outputStream;
static SerialPort serialPort;
HashMap serialParams;
Thread readThread;//本来是static类型的
//端口是否打开了
boolean isOpen = false;
// 端口读入数据事件触发后,等待n毫秒后再读取,以便让数据一次性读完
public static final String PARAMS_DELAY = "delay read"; // 延时等待端口数据准备的时间
public static final String PARAMS_TIMEOUT = "timeout"; // 超时时间
public static final String PARAMS_PORT = "port name"; // 端口名称
public static final String PARAMS_DATABITS = "data bits"; // 数据位
public static final String PARAMS_STOPBITS = "stop bits"; // 停止位
public static final String PARAMS_PARITY = "parity"; // 奇偶校验
public static final String PARAMS_RATE = "rate"; // 波特率
public boolean isOpen(){
return isOpen;
}
/**
* 初始化端口操作的参数.
* @throws SerialPortException
*
* @see
*/
public SerialReader()
{
isOpen = false;
}
public void open(HashMap params)
{
serialParams = params;
if(isOpen){
close();
}
try
{
// 参数初始化
int timeout = Integer.parseInt( serialParams.get( PARAMS_TIMEOUT )
.toString() );
int rate = Integer.parseInt( serialParams.get( PARAMS_RATE )
.toString() );
int dataBits = Integer.parseInt( serialParams.get( PARAMS_DATABITS )
.toString() );
int stopBits = Integer.parseInt( serialParams.get( PARAMS_STOPBITS )
.toString() );
int parity = Integer.parseInt( serialParams.get( PARAMS_PARITY )
.toString() );
delayRead = Integer.parseInt( serialParams.get( PARAMS_DELAY )
.toString() );
String port = serialParams.get( PARAMS_PORT ).toString();
// 打开端口
portId = CommPortIdentifier.getPortIdentifier( port );
serialPort = ( SerialPort ) portId.open( "SerialReader", timeout );
inputStream = serialPort.getInputStream();
serialPort.addEventListener( this );
serialPort.notifyOnDataAvailable( true );
serialPort.setSerialPortParams( rate, dataBits, stopBits, parity );
isOpen = true;
}
catch ( PortInUseException e )
{
// 端口"+serialParams.get( PARAMS_PORT ).toString()+"已经被占用";
}
catch ( TooManyListenersException e )
{
//"端口"+serialParams.get( PARAMS_PORT ).toString()+"监听者过多";
}
catch ( UnsupportedCommOperationException e )
{
//"端口操作命令不支持";
}
catch ( NoSuchPortException e )
{
//"端口"+serialParams.get( PARAMS_PORT ).toString()+"不存在";
}
catch ( IOException e )
{
//"打开端口"+serialParams.get( PARAMS_PORT ).toString()+"失败";
}
serialParams.clear();
Thread readThread = new Thread( this );
readThread.start();
}
public void run()
{
try
{
Thread.sleep(50);
}
catch ( InterruptedException e )
{
}
}
public void start(){
try {
outputStream = serialPort.getOutputStream();
}
catch (IOException e) {}
try{
readThread = new Thread(this);
readThread.start();
}
catch (Exception e) { }
} //start() end
public void run(String message) {
try {
Thread.sleep(4);
}
catch (InterruptedException e) { }
try {
if(message!=null&&message.length()!=0)
{
System.out.println("run message:"+message);
outputStream.write(message.getBytes());
}
} catch (IOException e) {}
}
public void close()
{
if (isOpen)
{
try
{
serialPort.notifyOnDataAvailable(false);
serialPort.removeEventListener();
inputStream.close();
serialPort.close();
isOpen = false;
} catch (IOException ex)
{
//"关闭串口失败";
}
}
}
public void serialEvent( SerialPortEvent event )
{
try
{
Thread.sleep( delayRead );
}
catch ( InterruptedException e )
{
e.printStackTrace();
}
switch ( event.getEventType() )
{
case SerialPortEvent.BI: // 10
case SerialPortEvent.OE: // 7
case SerialPortEvent.FE: // 9
case SerialPortEvent.PE: // 8
case SerialPortEvent.CD: // 6
case SerialPortEvent.CTS: // 3
case SerialPortEvent.DSR: // 4
case SerialPortEvent.RI: // 5
case SerialPortEvent.OUTPUT_BUFFER_EMPTY: // 2
break;
case SerialPortEvent.DATA_AVAILABLE: // 1
try
{
// 多次读取,将所有数据读入
while (inputStream.available() > 0) {
numBytes = inputStream.read(readBuffer);
}
//打印接收到的字节数据的ASCII码
for(int i=0;i<numBytes;i++){
// System.out.println("msg[" + numBytes + "]: [" +readBuffer[i] + "]:"+(char)readBuffer[i]);
}
// numBytes = inputStream.read( readBuffer );
changeMessage( readBuffer, numBytes );
}
catch ( IOException e )
{
e.printStackTrace();
}
break;
}
}
// 通过observer pattern将收到的数据发送给observer
// 将buffer中的空字节删除后再发送更新消息,通知观察者
public void changeMessage( byte[] message, int length )
{
setChanged();
byte[] temp = new byte[length];
System.arraycopy( message, 0, temp, 0, length );
notifyObservers( temp );
}
static void listPorts()
{
Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();
while ( portEnum.hasMoreElements() )
{
CommPortIdentifier portIdentifier = ( CommPortIdentifier ) portEnum
.nextElement();
}
}
public void openSerialPort(String message)
{
HashMap<String, Comparable> params = new HashMap<String, Comparable>();
otherDAO odao=new otherDAO();
String port=odao.selectNumberById(15);
String rate = "9600";
String dataBit = ""+SerialPort.DATABITS_8;
String stopBit = ""+SerialPort.STOPBITS_1;
String parity = ""+SerialPort.PARITY_NONE;
int parityInt = SerialPort.PARITY_NONE;
params.put( SerialReader.PARAMS_PORT, port ); // 端口名称
params.put( SerialReader.PARAMS_RATE, rate ); // 波特率
params.put( SerialReader.PARAMS_DATABITS,dataBit ); // 数据位
params.put( SerialReader.PARAMS_STOPBITS, stopBit ); // 停止位
params.put( SerialReader.PARAMS_PARITY, parityInt ); // 无奇偶校验
params.put( SerialReader.PARAMS_TIMEOUT, 100 ); // 设备超时时间 1秒
params.put( SerialReader.PARAMS_DELAY, 100 ); // 端口数据准备时间 1秒
try {
open(params);//打开串口
LoginFrame cf=new LoginFrame();
addObserver(cf);
if(message!=null&&message.length()!=0)
{
String str="";
for(int i=0;i<10;i++)
{
str+=message;
}
start();
run(str);
}
} catch (Exception e) {
}
}
static String getPortTypeName( int portType )
{
switch ( portType )
{
case CommPortIdentifier.PORT_I2C:
return "I2C";
case CommPortIdentifier.PORT_PARALLEL:
return "Parallel";
case CommPortIdentifier.PORT_RAW:
return "Raw";
case CommPortIdentifier.PORT_RS485:
return "RS485";
case CommPortIdentifier.PORT_SERIAL:
return "Serial";
default:
return "unknown type";
}
}
public HashSet<CommPortIdentifier> getAvailableSerialPorts()//本来static
{
HashSet<CommPortIdentifier> h = new HashSet<CommPortIdentifier>();
Enumeration thePorts = CommPortIdentifier.getPortIdentifiers();
while ( thePorts.hasMoreElements() )
{
CommPortIdentifier com = ( CommPortIdentifier ) thePorts
.nextElement();
switch ( com.getPortType() )
{
case CommPortIdentifier.PORT_SERIAL:
try
{
CommPort thePort = com.open( "CommUtil", 50 );
thePort.close();
h.add( com );
}
catch ( PortInUseException e )
{
System.out.println( "Port, " + com.getName()
+ ", is in use." );
}
catch ( Exception e )
{
System.out.println( "Failed to open port "
+ com.getName() + e );
}
}
}
return h;
}
}
//ASCII表
//-------------------------------------------------------------
// ASCII Characters
//
//Dec Hex Char Code Dec Hex Char
//
//0 0 NUL 64 40 @
//1 1 SOH 65 41 A
//2 2 STX 66 42 B
//3 3 ETX 67 43 C
//4 4 EOT 68 44 D
//5 5 ENQ 69 45 E
//6 6 ACK 70 46 F
//7 7 BEL 71 47 G
//8 8 BS 72 48 H
//9 9 HT 73 49 I
//10 0A LF 74 4A J
//11 0B VT 75 4B K
//12 0C FF 76 4C L
//13 0D CR 77 4D M
//14 0E SO 78 4E N
//15 0F SI 79 4F O
//16 10 SLE 80 50 P
//17 11 CS1 81 51 Q
//18 12 DC2 82 52 R
//19 13 DC3 83 53 S
//20 14 DC4 84 54 T
//21 15 NAK 85 55 U
//22 16 SYN 86 56 V
//23 17 ETB 87 57 W
//24 18 CAN 88 58 X
//25 19 EM 89 59 Y
//26 1A SIB 90 5A Z
//27 1B ESC 91 5B [
// 92 5C \
//28 1C FS 93 5D ]
//29 1D GS 94 5E ^
//30 1E RS 95 5F _
//31 1F US 96 60 `
//32 20 (space) 97 61 a
//33 21 ! 98 62 b
//34 22 "
// 99 63 c
//35 23 # 100 64 d
//36 24 $
//37 25 % 101 65 e
//38 26 & 102 66 f
//39 27 ' 103 67 g
//40 28 ( 104 68 h
//41 29 ) 105 69 i
//42 2A * 106 6A j
//43 2B + 107 6B k
//44 2C , 108 6C l
//45 2D - 109 6D m
//46 2E . 110 6E n
//47 2F / 111 6F o
//48 30 0 112 70 p
//49 31 1 113 72 q
//50 32 2 114 72 r
//51 33 3 115 73 s
//52 34 4 116 74 t
//53 35 5 117 75 u
//54 36 6 118 76 v
//55 37 7 119 77 w
//56 38 8 120 78 x
//57 39 9 121 79 y
//58 3A : 122 7A z
//59 3B ; 123 7B {
//60 3C < 124 7C |
//61 3D = 125 7D }
//62 3E > 126 7E ~
//63 3F ? 127 7F看完上述内容是否对您有帮助呢？如果还想对相关知识有进一步的了解或阅读更多相关文章，请关注亿速云行业资讯频道，感谢您对亿速云的支持。
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