我有一个 Java 程序，我必须在其中读取 Arduino 发送的信息.我从 here 获取了 Java 代码.现在，我真的不明白它是如何工作的，但我尝试修改它并得到了这个:
I've got a program in Java where I have to read the information that an Arduino is sending. I took the Java code from here. Now, I didn't really understand how it works, but I tried to modify it and I got this:
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 Serial implements SerialPortEventListener {
SerialPort serialPort;
private static final String PORT_NAMES[] = {
"/dev/tty.usbserial-A9007UX1", // Mac OS X
"/dev/ttyUSB0", // Linux
"COM3", // Windows
};
private BufferedReader input;
private static OutputStream output;
private static final int TIME_OUT = 2000;
private static final int DATA_RATE = 115200;
public void initialize() {
CommPortIdentifier portId = null;
Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();
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 {
serialPort = (SerialPort) portId.open(this.getClass().getName(),TIME_OUT);
serialPort.setSerialPortParams(DATA_RATE, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);
input = new BufferedReader(new InputStreamReader(serialPort.getInputStream()));
output = serialPort.getOutputStream();
serialPort.addEventListener(this);
serialPort.notifyOnDataAvailable(true);
}
catch (Exception e) {
System.err.println(e.toString());
}
}
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());
}
}
}
public synchronized void close() {
if (serialPort != null) {
serialPort.removeEventListener();
serialPort.close();
}
}
public Serial(String ncom){
if(Integer.parseInt(ncom)>=3 && Integer.parseInt(ncom)<=9)
PORT_NAMES[2] = "COM" + ncom;
initialize();
Thread t=new Thread() {
public void run() {
try {Thread.sleep(1000000);} catch (InterruptedException ie) {}
}
};
t.start();
System.out.println("Serial Comms Started");
}
public synchronized void send(int b){
try{
output.write(b);
}
catch (Exception e) {
System.err.println(e.toString());
}
}
public synchronized int read(){
int b = 0;
try{
b = (int)input.read();
}
catch (Exception e) {
System.err.println(e.toString());
}
return b;
}
}
我在主程序中使用 COM 端口 创建对象 Serial，然后我在需要时使用 Serial.read 和 Serial.write.
I create the object Serial with the COM port I need in the main program, then I use Serial.read and Serial.write when I need it.
Serial.write 效果很好，Arduino 获取数据并将其显示在 LCD 显示器中.问题是 Serial.read.当程序运行时，它会从串口读取数据(大约每 40 毫秒)，但这并不意味着 Arduino 发送了一些东西.Arduino 仅在按下按钮时发送一个字节.因此，当 Java 代码运行时，它会在读取内容之前抛出n"异常，这会造成很大的延迟.
Serial.write works great, Arduino gets the data and show it in a LCD Display. The problem is Serial.read. When the program is running, it keep read from serial port (around every 40 ms), but that doesn't mean Arduino sent something. Arduino sends a byte only when a button is pushed. So, when the Java code is running, it throws "n" Exception before read something, and this couses so much lag.
我知道我需要类似 Serial.available() 的东西，我尝试了 input.available()，但它不起作用.我不知道如何解决这个问题.
I know I need something like Serial.available(), I tried input.available(), but it doesn't work. I don't know how to solve this problem.
如果你有一个有效的代码，如果你能把它给我，我会非常感激.我只需要两种方法，读和写，我不在乎代码是如何工作的:D
If you have a code that working, I'd be so much grateful if you could give it to me. I just need two methods, read and write, I don't care how the code works :D
我更改了 Serial 类，现在它又像 apremalal 所说的那样具有这种方法
I changed the Serial class, now it has again this method as apremalal said
public synchronized void serialEvent(SerialPortEvent oEvent) {
if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
try {
String inputLine=null;
if (input.ready()) {
inputLine = input.readLine();
panel.read(inputLine);
}
} catch (Exception e) {
System.err.println(e.toString());
}
}
}
在另一个班级(在这种情况下为面板)我有这个:
and in the other class (Panel in this case) I've got this:
public void read(String data){
System.out.println(data);
System.out.println(data == "255");
if(data == "255")
//code here
}
它正确打印值，但 data == "255" 总是错误的，即使我真的得到 255....我试图做 Integer.parseInt 但没有任何改变.为什么?
It print the values correctly but data == "255" is always false, even if I really get a 255
....I tried to do Integer.parseInt but nothing changed. Why the hell?
好的解决了:
public void read(String data){
serialRead = Integer.parseInt(data);
if(serialRead == 255)
//code here
}
现在它的工作..不知道为什么我必须这样做...嗯，随便 :)
Now it's work..don't know why I had to do this... meh whatever :)
您不想专门编写一个读取函数，它已经存在于示例代码中.正如 TheMerovingian 指出的，您可以在读取之前检查输入缓冲区.这里是我在其中一个项目中使用的工作代码.
You don't want to specifically write a read function it's already there in the sample code.As TheMerovingian pointed out you can check the input Buffer before reading.Here is the working code which I have used in one of my projects.
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 SerialTest implements SerialPortEventListener {
SerialPort serialPort;
/** The port we're normally going to use. */
private static final String PORT_NAMES[] = { "/dev/tty.usbserial-A9007UX1", // Mac OS X
"/dev/ttyUSB0", // Linux
"COM35", // Windows
};
private BufferedReader input;
private OutputStream output;
private static final int TIME_OUT = 2000;
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 {
serialPort = (SerialPort) portId.open(this.getClass().getName(),
TIME_OUT);
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();
serialPort.addEventListener(this);
serialPort.notifyOnDataAvailable(true);
} catch (Exception e) {
System.err.println(e.toString());
}
}
public synchronized void close() {
if (serialPort != null) {
serialPort.removeEventListener();
serialPort.close();
}
}
public synchronized void serialEvent(SerialPortEvent oEvent) {
if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
try {
String inputLine=null;
if (input.ready()) {
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 {
SerialTest main = new SerialTest();
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");
}
}
serialEvent 函数负责读取缓冲区.
EDIT : serialEvent function is responsible for reading the buffer.
public synchronized void serialEvent(SerialPortEvent oEvent) {
if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
try {
String inputLine=null;
if (input.ready()) {
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.
}
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