public String init(int baudRate) {
        //获取系统中可用的端口
        portList = CommPortIdentifier.getPortIdentifiers();
        while (portList.hasMoreElements()) {
            portId = (CommPortIdentifier) portList.nextElement();
            System.out.println("发现端口：" + portId.getName());
            return portId.getName();
        }
        return null;
}

public void connect(String portName) throws Exception {
        CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(portName);
        if (portIdentifier.isCurrentlyOwned()) {
            System.out.println("Error: Port is currently in use");
        } else {
            CommPort commPort = portIdentifier.open(this.getClass().getName(), 2000);
            if (commPort instanceof SerialPort) {
                SerialPort serialPort = (SerialPort) commPort;
                serialPort.setSerialPortParams(9600, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);

                InputStream in = serialPort.getInputStream();

                SerialReader serialReader = new SerialReader(in);
                serialReader.setCallBack(this);
                (new Thread(serialReader)).start();

            } else {
                System.out.println("Error: Only serial ports are handled by this example.");
            }
        }
    }

public static class SerialReader implements Runnable {
        InputStream in;
        DataCallBack callBack;

        public void setCallBack(DataCallBack callBack) {
            this.callBack = callBack;
        }

        public SerialReader(InputStream in) {
            this.in = in;
        }

        String getValue = "";

        public void run() {

            byte[] buffer = new byte[1024];
            int len = -1;
            try {

                do {
                    len = this.in.read(buffer);
                        getValue += new String(buffer,0,len);

                    if (getValue != null && getValue.length() > 2){
                        System.out.println(getValue);
                        System.out.println("#############################");

                        if (callBack != null) {
                            callBack.onGetData(getValue);
                            getValue = "";
                        }
                    }
                }while (len > -1);
            } catch (IOException e) {
                e.printStackTrace();
            }

        }

package com.hziee.scanner.domain.tools;

public interface DataCallBack {
    void onGetData(String data);
}

@Override
public void onGetData(String data) {
    this.result = data;
    System.out.println("callback--" + data);
    runMethod(result);
}

DataCallBack callBack;

public void setCallBack(DataCallBack callBack) {
    this.callBack = callBack;
}

if (callBack != null) {
                            callBack.onGetData(getValue);
                            getValue = "";
                        }

serialReader.setCallBack(this);

Test4 t = new Test4();
String port = t.init(9600);

try {
    t.connect(port);
} catch (Exception e) {
    e.printStackTrace();
}