java 串口通信详细及简单实例

时间:2021-07-17 01:41:30

java 实现串口通信

最近做了一个与硬件相关的项目,刚开始听说用java和硬件打交道,着实下了一大跳。java也可以操作硬件?

后来接触到是用java通过串口通信控制硬件感觉使用起来还不错,也很方便。

特拿出来和大家一起分享一下。

准备工作:

首先到SUN官网下载一个zip包:javacomm20-win32.zip

其中重要的有这几个文件:

win32com.dll

comm.jar

javax.comm.properties

按照说明配置好环境,如下:

将win32com.dll复制到<JDK>\bin目录下;将comm.jar复制到<JDK>\lib;把 javax.comm.properties也同样拷贝到<JDK>\lib目录下。然而在真正运行使用串口包的时候,仅作这些是不够的。因 为通常当运行“java MyApp”的时候,是由JRE下的虚拟机启动MyApp的。而我们只复制上述文件到JDK相应目录下,所以应用程序将会提示找不到串口。解决这个问题的 方法很简单,我们只须将上面提到的文件放到JRE相应的目录下就可以了

到这一个可以java 串口开发环境就搭建完成了

确认本机可以使用的串口:

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package test;
 
import java.util.Enumeration;
import java.util.HashMap;
 
import javax.comm.CommPortIdentifier;
import javax.comm.SerialPort;
 
public class GetSerialPorts {
 
  public void listPortChoices() {
    CommPortIdentifier portId;
    Enumeration en = CommPortIdentifier.getPortIdentifiers();
    // iterate through the ports.
    while (en.hasMoreElements()) {
      portId = (CommPortIdentifier) en.nextElement();
      if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
        System.out.println(portId.getName());
      }
    }
 
  }
 
  public static void main(String[] args) {
 
    GetSerialPorts GSP = new GetSerialPorts();
    GSP.listPortChoices();
 
  }
 
}

打开串口,关闭串口:

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package test;
 
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Enumeration;
import java.util.HashMap;
 
import javax.comm.CommPortIdentifier;
import javax.comm.PortInUseException;
import javax.comm.SerialPort;
import javax.comm.UnsupportedCommOperationException;
 
public class GetSerialPorts {
 
  private CommPortIdentifier portId;
 
  private SerialPort testPort;
 
  private CommPortIdentifier myPort;
 
  private InputStream is;
 
  private OutputStream os;
 
  public void listPortChoices() {
 
    Enumeration en = CommPortIdentifier.getPortIdentifiers();
    // iterate through the ports.
    while (en.hasMoreElements()) {
      portId = (CommPortIdentifier) en.nextElement();
      if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
        System.out.println(portId.getName());
      }
      myPort = portId;// 任意取一个串口,比如com1
    }
 
  }
 
  public boolean openPort() {
    try {
      testPort = (SerialPort) myPort.open("COM1", 500);// 注意这里必须换成一个真实的串口
      try {
        this.testPort.setSerialPortParams(38400, SerialPort.DATABITS_8,
            SerialPort.STOPBITS_1, SerialPort.PARITY_EVEN);
      } catch (UnsupportedCommOperationException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
      try {
        this.testPort.enableReceiveTimeout(30);
      } catch (UnsupportedCommOperationException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
      this.testPort.setOutputBufferSize(1024);
      this.testPort.setInputBufferSize(1024);
 
      try {
        this.is = this.testPort.getInputStream();
      } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
      try {
        this.os = this.testPort.getOutputStream();
      } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
      this.testPort.notifyOnDataAvailable(true);
      this.testPort.notifyOnOutputEmpty(true);
      this.testPort.notifyOnBreakInterrupt(true);
 
      // this.printerPort.addEventListener(new PrintPortListener(is));
      System.out.println("打开com1机串口成功");
      return true;
    } catch (PortInUseException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
      return false;
    }
 
  }
 
  /**
   * TODO 关闭端口
   *
   * @param
   * @return Map
   * @throws
   */
  public boolean closePort() {
    // TODO Auto-generated method stub
    try {
      if (null != this.testPort) {
        is.close();
        os.close();
        this.testPort.close();
      }
      System.out.println("关闭COM1串口成功");
      return true;
    } catch (Exception e) {
      // TODO Auto-generated catch block
      // e.printStackTrace();
      System.out.println("关闭COM1串口失败");
      return false;
    }
  }
 
  public static void main(String[] args) {
 
    GetSerialPorts GSP = new GetSerialPorts();
    GSP.listPortChoices();
    GSP.openPort();
 
  }
 
}

读数据:

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/**
   * TODO 接收端口數據
   *
   * @param InputStream
   * @return String
   * @throws
   */
  public String readData(InputStream is) {
    // 读取缓冲区域
    byte[] readBuffer = new byte[4096];
    int readDataLength = 0;
    try {
      readDataLength = is.read(readBuffer);
      // for (byte b : readBuffer) {
      // System.out.print(b);
      // }
      // System.out.println();
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
      return null;
    }
    // 将真实数据保存到零时数组中
    byte[] readTemp = new byte[readDataLength];
    for (int i = 0; i < readDataLength; i++) {
      readTemp[i] = readBuffer[i];
    }
 
    // 将byte数组转换为16进制字符串
    String stringTemp = FeelTheBase.bytesToHexString(readTemp);
    // System.out.println("指令返回值" + stringTemp);
 
    return stringTemp;
 
  }

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