我正在尝试实现一个简单的代码来从超声波读取数据并使用 Californium 将其发送到服务器。问题是当我使用调试时，它没有任何错误。但是，当我将代码导出到可运行的 jar 文件并在我的树莓派上运行时，它会引发以下错误：
Exception in thread "main" java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:58)
Caused by: java.lang.NoClassDefFoundError: org/eclipse/californium/elements/util/NamedThreadFactory
at org.eclipse.californium.core.CoapServer.<init>(CoapServer.java:163)
at org.eclipse.californium.core.CoapServer.<init>(CoapServer.java:120)
at iot.main.device.DeviceClient.main(DeviceClient.java:34)
... 5 more
Caused by: java.lang.ClassNotFoundException: org.eclipse.californium.elements.util.NamedThreadFactory
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 8 more
我不确定是什么原因造成的以及如何解决它，任何建议都会很有帮助。下面是代码：
package iot.main.device;
import static org.eclipse.californium.core.coap.CoAP.ResponseCode.BAD_REQUEST;
import static org.eclipse.californium.core.coap.CoAP.ResponseCode.CHANGED;
import org.eclipse.californium.core.CoapClient;
import org.eclipse.californium.core.CoapResource;
import org.eclipse.californium.core.CoapResponse;
import org.eclipse.californium.core.CoapServer;
import org.eclipse.californium.core.coap.MediaTypeRegistry;
import org.eclipse.californium.core.server.resources.CoapExchange;
import com.pi4j.io.gpio.*;
public class DeviceClient {
private static GpioPinDigitalOutput sensorTriggerPin ;
private static GpioPinDigitalInput sensorEchoPin ;
final static GpioController gpio = GpioFactory.getInstance();
public static void main(String[] args) {
double ultraVal;
sensorTriggerPin = gpio.provisionDigitalOutputPin(RaspiPin.GPIO_04); // Trigger pin as OUTPUT
sensorEchoPin = gpio.provisionDigitalInputPin(RaspiPin.GPIO_05,PinPullResistance.PULL_DOWN); // Echo pin as INPUT
CoapClient client = new CoapClient("coap://localhost/Ultrasonic");
CoapServer server = new CoapServer();
server.add(new UltraResource());
server.start();
while(true){
try {
Thread.sleep(2000);
sensorTriggerPin.high(); // Make trigger pin HIGH
Thread.sleep((long) 0.00001);// Delay for 10 microseconds
sensorTriggerPin.low(); //Make trigger pin LOW
while(sensorEchoPin.isLow()){ //Wait until the ECHO pin gets HIGH
}
long startTime= System.nanoTime(); // Store the surrent time to calculate ECHO pin HIGH time.
while(sensorEchoPin.isHigh()){ //Wait until the ECHO pin gets LOW
}
long endTime= System.nanoTime(); // Store the echo pin HIGH end time to calculate ECHO pin HIGH time.
ultraVal = ((((endTime - startTime)/1e3)/2) / 29.1);
System.out.println("Distance : " + ultraVal + " cm"); //Printing out the distance in cm
Thread.sleep(1000);
CoapResponse response = client.put(Double.toString(ultraVal), MediaTypeRegistry.TEXT_PLAIN);
if (response!=null) {
System.out.println( response.getCode() );
System.out.println( response.getOptions() );
System.out.println( response.getResponseText() );
} else {
System.out.println("Request failed");
}
}
catch (InterruptedException e) {
e.printStackTrace();
}
}
}
public static class UltraResource extends CoapResource {
public String value = "Resource has not changed yet !!!";
public UltraResource() {
super("Ultrasonic");
setObservable(true);
}
@Override
public void handleGET(CoapExchange exchange) {
exchange.respond(value);
}
@Override
public void handlePUT(CoapExchange exchange) {
String payload = exchange.getRequestText();
System.out.println(payload + " cm");
try {
exchange.respond(CHANGED, payload);
value = new String(payload);
changed();
} catch (Exception e) {
e.printStackTrace();
exchange.respond(BAD_REQUEST, "Invalid String");
}
}
}
}