Question

首先让我介绍一下我的程序。我的应用程序纯java并使用comm jar for com port。我已经添加了

win32com.dll - jre/bin
comm.jar - jre/lib/ext
java.comm.properties - jre/liv

以下是我的程序

import java.io.InputStream;
import java.io.OutputStream;
import java.util.Enumeration;

import javax.comm.CommPortIdentifier;
import javax.comm.SerialPort;

public class PortReaderWriter
{
    static Enumeration<?> ports;
    static CommPortIdentifier portId;
    static InputStream inputStream;
    static OutputStream outputStream;
    static SerialPort serialPort;
    static String messageString = "abc";

    public static void main(String[] args) throws Exception
    {
        try
        {
            ports = CommPortIdentifier.getPortIdentifiers();

            while (ports.hasMoreElements())
            {
                portId = (CommPortIdentifier) ports.nextElement();
                System.out.println("Port " + portId.getName());

                if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL)
                {
                    if (portId.getName().equals("COM1"))
                    {
                        System.out.println("====================");
                        System.out.println("COM1 found");

                        serialPort = (SerialPort) portId.open("PortReaderWriter", 2000);
                        serialPort
                                .setSerialPortParams(9600, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);

                        outputStream = serialPort.getOutputStream();
                        outputStream.write(messageString.getBytes());
                        System.out.println(messageString.getBytes() + "  Successfully Sent!");

                        inputStream = serialPort.getInputStream();
                        byte[] readBuffer = new byte[2048];
                        while (inputStream.available() > 0)
                        {
                            int numBytes = inputStream.read(readBuffer);
                            System.out.println("numBytes " + numBytes);
                        }
                        System.out.print(new String(readBuffer));

                        outputStream = serialPort.getOutputStream();
                        outputStream.write(messageString.getBytes());
                        System.out.println(messageString.getBytes() + "  Successfully Sent!");

                        System.out.println("====================");
                    }
                }
            }
        } catch (Exception e)
        {
            e.printStackTrace();
        }
    }
}

输出

Port COM3
Port COM1
====================
COM1 found
[B@1a52fdf  Successfully Sent!

====================
Port LPT1
Port LPT2

但是我的预期输出是

COM1 found
[B@1a52fdf  Successfully Sent!
abc
====================
Port LPT1
Port LPT2

在程序中，我不确定是否发送了“abc”，并且在输出中我看不到。请帮助我是否需要添加或更改。提前谢谢！

Answer 1

以下语句中的messageString.getBytes()返回一个字节数组而不是字符串本身：

System.out.println(messageString.getBytes() + "  Successfully Sent!");

这就是为什么你得到一个[B@1a52fdf而不是消息本身。

当然，当您发送数据时，您发送一个字节数组，但如果您希望查看以字符串形式发送的内容，可以使用以下内容：

System.out.println(messageString + "  Successfully Sent!");

此外，语句System.out.println("Port " + portId.getName());打印每个端口名称;如果您只希望显示根据您的条件找到的端口的端口名称（如您所需输出中缺少Port COM3和Port COM1），则可以省略此语句。

Java com端口读写问题

1 个答案: