如何调用字符串在另一个类中出现

Question

我有一门课叫主修课。爪哇。在此，输出由inputLine显示，它是从com端口连续获取的字符串。我想让这个字符串值用在同一个默认包中的其他类中。如何在其他类中调用此字符串。我如何创建这个类的实例，并调用任何其他XYZ.java类中的字符串inputLine。举个例子会很有帮助。

    import java.io.BufferedReader;
    import java.io.InputStreamReader;
    import java.io.OutputStream;
    import gnu.io.CommPortIdentifier;
    import gnu.io.SerialPort;
    import gnu.io.SerialPortEvent;
    import gnu.io.SerialPortEventListener;
    import java.util.Enumeration;


public class Main implements SerialPortEventListener
{
    SerialPort serialPort;
        /** The port we're normally going to use. */
    private static final String PORT_NAMES[] = {
            "COM30", // Windows
    };
    /**
    * A BufferedReader which will be fed by a InputStreamReader
    * converting the bytes into characters
    * making the displayed results codepage independent
    */
    private BufferedReader input;
    /** The output stream to the port */
    private OutputStream output;
    /** Milliseconds to block while waiting for port open */
    private static final int TIME_OUT = 2000;
    /** Default bits per second for COM port. */
    private static final int DATA_RATE = 9600;

    public void initialize() {
        CommPortIdentifier portId = null;
        Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();

        //First, Find an instance of serial port as set in PORT_NAMES.
        while (portEnum.hasMoreElements()) {
            CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
            for (String portName : PORT_NAMES) {
                if (currPortId.getName().equals(portName)) {
                    portId = currPortId;
                    break;
                }
            }
        }
        if (portId == null) {
            System.out.println("Could not find COM port.");
            return;
        }

        try {
            // open serial port, and use class name for the appName.
            serialPort = (SerialPort) portId.open(this.getClass().getName(),
                    TIME_OUT);

            // set port parameters
            serialPort.setSerialPortParams(DATA_RATE,
                    SerialPort.DATABITS_8,
                    SerialPort.STOPBITS_1,
                    SerialPort.PARITY_NONE);

            // open the streams
            input = new BufferedReader(new InputStreamReader(serialPort.getInputStream()));
            output = serialPort.getOutputStream();

            // add event listeners
            serialPort.addEventListener(this);
            serialPort.notifyOnDataAvailable(true);
        } catch (Exception e) {
            System.err.println(e.toString());
        }
    }

    /**
     * This should be called when you stop using the port.
     * This will prevent port locking on platforms like Linux.
     */
    public synchronized void close() {
        if (serialPort != null) {
            serialPort.removeEventListener();
            serialPort.close();
        }
    }

    /**
     * Handle an event on the serial port. Read the data and print it.
     */
    public synchronized void serialEvent(SerialPortEvent oEvent) {
        if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
            try {
                String inputLine=input.readLine();
                System.out.println(inputLine);

            } catch (Exception e) {
                System.err.println(e.toString());
            }
        }
        // Ignore all the other eventTypes, but you should consider the other ones.
    }

    public static void main(String[] args) throws Exception {
        Main main = new Main();
        main.initialize();
        Thread t=new Thread() {
            public void run() {
                //the following line will keep this app alive for 1000 seconds,
                //waiting for events to occur and responding to them (printing incoming messages to console).
                try {Thread.sleep(1000000);} catch (InterruptedException ie) {}
            }
        };
        t.start();
        System.out.println("Started");
    }
}

Answer 1

在您的情况下，您应该只创建一个类变量。只需在类内部声明，public static String inputline；Change String inputline=input.readline()；到inputline=input.readline()；，您可以使用main.inputline，从同一包中的其他类访问它。