I have a method that can execute a Exception, I dont now how to redirect to a web page inside templates. If it happen the exception
#ResponseStatus(HttpStatus.NOT_FOUND)
public class NoCordInRouteFoundException extends RuntimeException {
}
Rather than using annotations directly on top of the exception, you can define an exception handler by using the #ExceptionHandler annotation:
#ResponseStatus(HttpStatus.NOT_FOUND)
#ExceptionHandler(NoCordInRouteFoundException.class)
public String noCordInRouteFound(NoCordInRouteFoundException ex) {
return "template";
}
Add this method to a specific controller to be able to use a specific template when an exception is thrown in any of the other methods within the controller, or add the method within a separate class annotated with #ControllerAdvice so that it will be applied for all controllers.
Related
I do have a Spring boot controller class and a corresponding ControllerAdvice class which has ExceptionHandlers to handle different exception.
My controller method calls a simple validation helper class to validate input fields which throws an exception if validation fails. Now if I don't put a try catch block in my controller it keeps complaining me that you have a method which has untangled exception even through the logic for handling validation exception is defined in controlleradvice class. Please suggest how do I solve it.
From the method of ValidationHelper class if you throw any Checked Exception then you need to use a try-catch block to call that method.
If you don't want then it's better to use any Custom Exception class which will extend the RuntimeException class and you throw that exception. Then you don't need to explicitly mention the throws as well as you don't need to have a try-catch block at the controller.
#RestController
#RequiredArgsConstructor
public class SampleController {
private final ValidationHelper validationHelper;
#ResponseStatus(HttpStatus.OK)
#GetMapping("/sample")
public String getRequest(#RequestParam String name) {
validationHelper.validate(name);
return "";
}
}
#Service
public class ValidationHelper {
public Boolean validate(String name) {
throw new CustomException("Validation Failed");
}
}
public class CustomException extends RuntimeException {
public CustomException(String message) {
super(message);
}
}
My Spring boot app is standalone application which don't have controller. I am calling service layer from main method of spring boot application.
I have tried to use #ExceptionHandler #ControllerAdvice annotations in my class as below. but control never comes to My Exception Handler method
package com.test.exception;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
#ControllerAdvice
public class MyExceptionHandler {
#ExceptionHandler(NullPointerException.class)
public void handleNullpointerExcetion() {
System.out.println("Handling Null pointer exception");
}
}
Tried with package name as well which i need to scan in #ControllerAdvice but it is not working
#ControllerAdvice("com.test.utility")
public class MyExceptionHandler {
#ExceptionHandler(NullPointerException.class)
public void handleNullpointerExcetion() {
System.out.println("Handling Null pointer exception");
}
}
Are we not able to handle exception at centralized place if i we don't have controller class which we annotate with #RestContoller or #Controller
I don't think so.
ControllerAdvice is only used whenever a controller would return an exception,
It is a layer that exists after your endpoint in the controller returns and before actually returning the response, to interject and globally handle the exception and is meant to be global only for controllers.
https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/bind/annotation/ControllerAdvice.html
since you don't have a controller, I'd imagine the ControllerAdvice will not help you there.
If you want a centralized error handling mechanism, you'd have to implement something similar to the controller advice yourself around your "Main" function, to which you can have unified exception handling responses.
I have defined ExceptionHandler with #ControllerAdvice and catches the following
Exception.class, Throwable.class, SQLException.class
When a user enters a page which doesn't exist or not available in the server. circular view page error is being displayed in the log and ExceptionHandler is not getting called.
What are the usual checkpoints to make the API error to get caught in CustomExceptionHandler. Not sure whether any tomcat hooks to be defined.
Using Spring Boot 2.0 and Spring version 5.0
Thanks.
In case : user enters a page/resource which does not exist, no exception is thrown. So your code does not work (I believe your code is similar to following code)
#ControllerAdvice
public class ErrorHandler {
#ExceptionHandler(Exception.class)
public String handle() {
....
return "error"
}
}
In order to make it work you need to extend yourhandler class from ResponseEntityExceptionHandler as
#ControllerAdvice
public class ErrorHandler extends ResponseEntityExceptionHandler {
...
}
And You need to override the following method
handleHttpMediaTypeNotSupported
handleHttpMediaTypeNotSupported
Detailed guide can be found from
- https://blog.jayway.com/2013/02/03/improve-your-spring-rest-api-part-iii/
- http://www.baeldung.com/global-error-handler-in-a-spring-rest-api
Another way, You can override /error if there is fixed message in all general cases.
I am studying how to handle custom exception in Spring on a tutorial that show me this class named ExceptionHandler that implement the HandlerExceptionResolver Spring interface:
#Component
public class ExceptionHandler implements HandlerExceptionResolver {
private static final Logger logger = LoggerFactory.getLogger(ExceptionHandler.class);
#Override
public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object object, Exception exception) {
System.out.println("Spring MVC Exception Handling");
logger.error("Error: ", exception);
return new ModelAndView("error/exception","exception","ExceptionHandler message: " + exception.toString());
}
}
And then, into a controller class of the example, it throws this exception in this way:
#RequestMapping(value="/throwRunTimeException", method=RequestMethod.GET)
public void throwException() {
throw new RuntimeException();
}
So I have some doubts about how exactly do this class.
I can't understand if implementing the HandlerExceptionResolver interface I am declaring a new specific exception type or if simply specify a specific behavior that happens when a generic runtime exception is thrown.
It seems me the second situation...I think that, in the previous example, when a generic RuntimeException is thrown it return an exception.jsp page (and the related message that have to be shown into the model object).
So, if the previous assertion is true, can I use this method for the following pourpose?
I think that when a user try to open an URL that is it not mapped to any controller method a RuntimeException is thrown.
So, into the **resolveException()** method, can I extract the required URL from the HttpServletRequest request input parameter and use it to show a specific error message (that indicate that this URL not exist) into the returned view?
I don't think that is possible. When the DispatcherServlet can't find the url mapped in one of your controllers, it will throw a NoHandlerFoundException. This will then be forwarded to your servlet container like Tomcat which handles the error and shows the 404 page for example. You can change this behaviour by adding the following to your web.xml:
`
<error-page>
<error-code>404</error-code>
<location>/WEB-INF/jsp/404error.jsp</location>
</error-page>
`
Note that it's not possible yet to configure this in JavaConfig.
For other Exceptions that are thrown you can use the HandlerExceptionResolver to return the desired view.
You could also use the #ExceptionHandler annotation on a method in your controller to catch the exceptions and handle them appropriately. This can be combined with the #ControllerAdvice annotation to enable this for every controller.
I have a Spring 3.2 application and I've created a REST API based on Spring MVC. I am using #ControllerAdvice annotation for custom exceptions handling. For example:
#ControllerAdvice
public class RestResponseEntityExceptionHandler {
#ExceptionHandler(MyCustomException.class)
#ResponseStatus(HttpStatus.CONFLICT)
#ResponseBody
public ExceptionMessage handleMyCustomException(MyCustomException ex){
return new ExceptionMessage(ex.getClass().getName(), ex.getMessage(), ex.getExceptionCode());
}
}
The issue is that I see how my custom exception is thrown but the exception handler method is actually not being executed and hence my exception message is not returned to the client. Instead, I noticed in the logs how the DefaultHandlerExceptionResolver handles the exception (with a Spring generic one, ServletRequestBindingException in a GET method). How can I get rid of this issue?
Thanks!
The ServletRequestBindingException is a hint that something went wrong before the handler method of the controller. In this case some binding issue.
Exception handlers annotated with #ExceptionHandler are only called when an exception is thrown within a controller handler method (#RequestMapping).