Cześć. Mam dość dziwny problem. Otóż przy próbie konwersji na typ Long pojawia się błąd java.lang.NullPointerException, który umieściłem poniżej. Cała idea polega na tym, że użytkownik wpisuje w pole TextField textDel id samochodu, który ma zostać usunięty z bazy danych H2. Następnie klika przycisk Button addBut w celu usunięcia rekordu. I tu pojawia się problem ponieważ po kliknięciu w przycisk pojawia się wcześniej wspomniany błąd. Za usuwanie jest odpowiedzialna funkcja delete, którą stworzyłem w klasie CarService. Za konwersje jest odpowiedzialny delBut.addClickListener gdzie po kliknięciu w przycisk formuła: carService.delete(Long.parseLong(textDel.getValue())); powinna dokonywać konwersji na typ Long oraz usuwać podany rekord
java.lang.NullPointerException: null
at com.example.cars.CarSave.lambda$new$f07aed0d$1(CarSave.java:33) ~[classes/:na]
at com.vaadin.flow.component.ComponentEventBus.fireEventForListener(ComponentEventBus.java:205) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.component.ComponentEventBus.handleDomEvent(ComponentEventBus.java:373) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.component.ComponentEventBus.lambda$addDomTrigger$dd1b7957$1(ComponentEventBus.java:264) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.internal.nodefeature.ElementListenerMap.lambda$fireEvent$2(ElementListenerMap.java:443) ~[flow-server-2.6.5.jar:2.6.5]
at java.base/java.util.ArrayList.forEach(ArrayList.java:1541) ~[na:na]
at com.vaadin.flow.internal.nodefeature.ElementListenerMap.fireEvent(ElementListenerMap.java:443) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.server.communication.rpc.EventRpcHandler.handleNode(EventRpcHandler.java:61) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.server.communication.rpc.AbstractRpcInvocationHandler.handle(AbstractRpcInvocationHandler.java:66) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.server.communication.ServerRpcHandler.handleInvocationData(ServerRpcHandler.java:412) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.server.communication.ServerRpcHandler.lambda$handleInvocations$1(ServerRpcHandler.java:393) ~[flow-server-2.6.5.jar:2.6.5]
at java.base/java.util.ArrayList.forEach(ArrayList.java:1541) ~[na:na]
at com.vaadin.flow.server.communication.ServerRpcHandler.handleInvocations(ServerRpcHandler.java:393) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.server.communication.ServerRpcHandler.handleRpc(ServerRpcHandler.java:320) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.server.communication.UidlRequestHandler.synchronizedHandleRequest(UidlRequestHandler.java:92) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:40) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.server.VaadinService.handleRequest(VaadinService.java:1570) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.server.VaadinServlet.service(VaadinServlet.java:252) ~[flow-server-2.6.5.jar:2.6.5]
at com.vaadin.flow.spring.SpringServlet.service(SpringServlet.java:111) ~[vaadin-spring-12.4.0.jar:na]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.50.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:228) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:711) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:353) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:313) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.springframework.web.servlet.mvc.ServletForwardingController.handleRequestInternal(ServletForwardingController.java:141) ~[spring-webmvc-5.3.9.jar:5.3.9]
at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:177) ~[spring-webmvc-5.3.9.jar:5.3.9]
at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:51) ~[spring-webmvc-5.3.9.jar:5.3.9]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1064) ~[spring-webmvc-5.3.9.jar:5.3.9]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.9.jar:5.3.9]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.9.jar:5.3.9]
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.3.9.jar:5.3.9]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:681) ~[tomcat-embed-core-9.0.50.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.9.jar:5.3.9]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.50.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:228) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.50.jar:9.0.50]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.9.jar:5.3.9]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.9.jar:5.3.9]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.9.jar:5.3.9]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.9.jar:5.3.9]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.9.jar:5.3.9]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.9.jar:5.3.9]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:190) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:163) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:382) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1723) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.50.jar:9.0.50]
at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
Oto moje klasy:
CarSave.java
@Route
public class CarSave extends HorizontalLayout {
private CarRepo carRepo;
private CarService carService;
TextField textMarka = new TextField("Marka");
TextField textModel = new TextField("Model");
TextField textPojemnosc = new TextField("Pojemnosc");
TextField textMoc = new TextField("Moc");
Button addBut = new Button("Dodaj");
TextField textDel = new TextField("Podaj id samochodu do usunięcia: ");
Button delBut = new Button("Usuń");
public CarSave(CarRepo carRepo) {
add(textMarka, textModel, textPojemnosc, textMoc, addBut,
new VerticalLayout(textDel, delBut));
addBut.addClickListener(clickEvent -> {
Car car = new Car(textMarka.getValue(), textModel.getValue(), textPojemnosc.getValue(), textMoc.getValue());
carRepo.save(car);
});
delBut.addClickListener(clickEvent -> {
this.carService = carService;
carService.delete(Long.parseLong(textDel.getValue()));
});
}
}
Car.java
@Entity
public class Car {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
private String marka;
private String model;
private String pojemnosc;
private String moc;
public Car() {
}
public Car(String marka, String model, String pojemnosc, String moc) {
this.marka = marka;
this.model = model;
this.pojemnosc = pojemnosc;
this.moc = moc;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getMarka() {
return marka;
}
public void setMarka(String marka) {
this.marka = marka;
}
public String getModel() {
return model;
}
public void setModel(String model) {
this.model = model;
}
public String getPojemnosc() {
return pojemnosc;
}
public void setPojemnosc(String pojemnosc) {
this.pojemnosc = pojemnosc;
}
public String getMoc() {
return moc;
}
public void setMoc(String moc) {
this.moc = moc;
}
@Override
public String toString() {
return "Car{" +
"id=" + id +
", marka='" + marka + '\'' +
", model='" + model + '\'' +
", pojemnosc='" + pojemnosc + '\'' +
", moc='" + moc + '\'' +
'}';
}
}
CarService.java
@Service
public class CarService {
private CarRepo carRepo;
public CarService(CarRepo carRepo) {
this.carRepo = carRepo;
}
public List<Car> findAll() {
return carRepo.findAll();
}
public void delete(Long id){
carRepo.deleteById(id);
}
}