1. Download
Address: http://fizzed.com/oss/rxtx-for-java
2. Deploy to Windows
After the download is complete, put the rxtxSerial.dll file into the corresponding directory of java (as shown in the figure)
Then import the RXTXcomm.jar package into the project or use maven to import it.
Import the local jar package directly
Create a new lib folder in the project root directory and import RXTXcomm.jar, and then import the local jar package in the pom
<dependency>
<groupId>com.test</groupId>
<artifactId>rxtxcomm</artifactId>
<version>2.2</version>
<scope>system</scope>
<systemPath>${basedir}/lib/RXTXcomm.jar</systemPath>
</dependency>Introduced by maven: write the following in pom
<dependency>
<groupId>org.bidib.jbidib.org.qbang.rxtx</groupId>
<artifactId>rxtxcomm</artifactId>
<version>2.2</version>
</dependency>3. Coding
import gnu.io.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Enumeration;
import java.util.TooManyListenersException;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
public class SerialPortDataHandle extends Thread implements SerialPortEventListener {
private static final Logger logger = LoggerFactory.getLogger(SerialPortDataHandle.class);
// 通讯端口管理，控制对通信端口的访问的中心类
static CommPortIdentifier portManager;
// 有效连接上的端口的枚举
static Enumeration<?> portList;
// 串口输入流引用
static InputStream inputStream;
// 串口输出流引用
static OutputStream outputStream;
// 串口对象引用
static SerialPort serialPort;
// 堵塞队列：用来存放串口发送到服务端的数据
private BlockingQueue<String> msgQueue = new LinkedBlockingQueue();
// 线程控制标识
private boolean flag = true;
public void serialEvent(SerialPortEvent event) {
switch (event.getEventType()) {
/*
* SerialPortEvent.BI:/*Break interrupt,通讯中断
* SerialPortEvent.OE:/*Overrun error，溢位错误
* SerialPortEvent.FE:/*Framing error，传帧错误
* SerialPortEvent.PE:/*Parity error，校验错误
* SerialPortEvent.CD:/*Carrier detect，载波检测
* SerialPortEvent.CTS:/*Clear to send，清除发送
* SerialPortEvent.DSR:/*Data set ready，数据设备就绪
* SerialPortEvent.RI:/*Ring indicator，响铃指示
* SerialPortEvent.OUTPUT_BUFFER_EMPTY:/*Output buffer is empty，输出缓冲区清空
*/
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;
// 当有可用数据时读取数据
case SerialPortEvent.DATA_AVAILABLE:
// 数据接收缓冲容器
byte[] readBuffer = new byte[200];
try {
// 存储待接收读取字节数大小
int numBytes = 0;
while (inputStream.available() > 0) {
numBytes = inputStream.read(readBuffer);
if (numBytes > 0) {
msgQueue.add(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
.format(new Date()) + " 收到的串口发送数据为："+ new String(readBuffer));
// 数据接收缓冲容器清空初始化
readBuffer = new byte[200];
}
}
} catch (IOException e) {
logger.error("IO异常", e);
}
break;
}
}
public int init() {
// 通过串口通信管理类获得当前连接上的端口列表
//（获取一个枚举对象，该CommPortIdentifier对象包含系统中每个端口的对象集[串口、并口]）
portList = CommPortIdentifier.getPortIdentifiers();
while (portList.hasMoreElements()) {
// 获取相应串口对象
portManager = (CommPortIdentifier) portList.nextElement();
/*
* 判断端口类型是否为串口
* PORT_SERIAL = 1; 【串口】
* PORT_PARALLEL = 2; 【并口】
* PORT_I2C = 3; 【I2C】
* PORT_RS485 = 4; 【RS485】
* PORT_RAW = 5; 【RAW】
*/
if (portManager.getPortType() == CommPortIdentifier.PORT_SERIAL) {
logger.info("串口设备名称：" + portManager.getName());
// 判断模拟COM4串口存在，就打开该串口
if (portManager.getName().equals("COM4")) {
logger.info("测试串口设备名称：" + portManager.getName());
try {
if (serialPort==null) {
// 打开串口，设置名字为COM_4(自定义),延迟阻塞时等待3000毫秒（赋值给预设的串口引用）
serialPort = (SerialPort)portManager.open("COM4", 3000);
logger.info("串口设备COM4已打开");
}
} catch (PortInUseException e) {
logger.error("串口使用异常", e);
return 0;
}
// 在串口引用不为空时进行下述操作
if (serialPort!=null) {
// 1. 设置串口的输入输出流引用
try {
inputStream = serialPort.getInputStream();
outputStream = serialPort.getOutputStream();
} catch (IOException e) {
logger.error("串口输入输出IO异常", e);
return 0;
}
// 2. 设置串口监听器
try {
serialPort.addEventListener(this);
} catch (TooManyListenersException e) {
logger.error("串口监听器添加异常", e);
return 0;
}
// 设置监听器在有数据时通知生效
serialPort.notifyOnDataAvailable(true);
// 3. 设置串口相关读写参数
try {
// 比特率、数据位、停止位、校验位
serialPort.setSerialPortParams(9600,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
} catch (UnsupportedCommOperationException e) {
logger.error("串口设置操作异常", e);
return 0;
}
return 1;
}
return 0;
}
}
}
return 0;
}
@Override
public void run() {
try {
logger.info("串口线程已运行");
while (flag) {
// 如果堵塞队列中存在数据就将其输出
if (msgQueue.size() > 0) {
// take() 取走BlockingQueue里排在首位的对象
// 若BlockingQueue为空，阻断进入等待状态直到Blocking有新的对象被加入为止
logger.info(msgQueue.take());
}
}
} catch (InterruptedException e) {
logger.error("线程执行异常", e);
}
}
public void stopGetDataBySerialPort() {
this.flag = false;
}
public static void main(String[] args) {
SerialPortDataHandle handle = new SerialPortDataHandle();
int i = handle.init();
if (i == 1) {
// 线程启动
handle.start();
}
}
}
4. Test
Need to download SerialPortUtility, vspd (Configure Virtual Serial Port Driver)
First, add COMM4 and COMM5 ports in vspd as shown in the figure, where COMM4 and COMM5 are connected together, which means that if I send data in COMM5, COMM4 can receive
Then we open SerialPortUtility, and configure the serial port parameters as shown in the figure (I chose COMM5), so that after we send a message in COMM5, COMM4 should be able to receive it
5. Matters needing attention
Java version! Java version! Java version! Say the important thing three times!
I just started using jdk1.8.0_261. Every time I send a message from interface 1 to interface 2, the service immediately crashes, and then reports this error:
I checked various articles on the Internet to no avail, and then I read that the error appeared to be related to the Java JDK version, so I tried to modify it to a lower version of JDK: jdk1.8.0_31, and it worked.
