I have the following RESTful Services method :
#PostMapping("/ajouterNewField")
public String ajouterField(#Valid #ModelAttribute("field") Fields field, Model model) throws IOException {
fieldDao.save(field);
// SOME CODE
return displayListeChamps( model);
}
The method is working fine and my question is how to handle any error (database not connected ...) or every issue that can happen durring the execution of this RESTful Services method.
You can use #ControllerAdvice
Refer to the code below
#ControllerAdvice
public String NyExceptionHandlerAdvice {
private final Logger logger = ...;
#ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
#ExceptionHandler({MyRunTimeException.class})
public void handleMyRunTimeException(Exception e) {
logger.error("Exception : ", e);
}
return MY_ERROR_STRING;
}
Best Practice is:
You can have your code throw RunTimeExceptions and handle all of them together or separately in handler methods similar to handleMyRunTimeException above.
You can decide what status code your request should return upon exception.
Basically you'll have to a sort of exception handler for any kind of exception your method might throw:
public class FooController{
// ...
#ExceptionHandler({ CustomException1.class, CustomException2.class })
public void handleException() {
//
}
}
Here's a nice article about that: https://www.baeldung.com/exception-handling-for-rest-with-spring
Related
I am new to String, SpringBoot.
Can we suppress thrown exception in a method annotated with #AfterThrowing?
I mean when an exception is thrown, it will suppress that and will return a default value on behalf of the invoking method?
Say, I have a controller -
#RestController
public class MyRestController implements IRestController{
#Override
#GetMapping("hello-throw")
public String mustThrowException(#RequestParam(value = "name")final String name) throws RuntimeException {
System.out.println("---> mustThrowException");
if("Bakasur".equals(name)) {
throw new RuntimeException("You are not welcome here!");
}
return name + " : Welcome to the club!!!";
}
}
I have created a #AspectJ, as follows -
#Aspect
#Component
public class MyAspect {
#Pointcut("execution(* com.crsardar.handson.java.springboot.controller.IRestController.*(..))")
public void executionPointcut(){
}
#AfterThrowing(pointcut="executionPointcut()",
throwing="th")
public String afterThrowing(JoinPoint joinPoint, Throwable th){
System.out.println("\n\n\tMyAspect : afterThrowing \n\n");
return "Exception handeled on behalf of you!";
}
}
If I run this & hit a ULR like - http://localhost:8080/hello-throw?name=Bakasur
I will get RuntimeException, but, I want to return a default message like - Exception handeled on behalf of you!, can we do it using #AfterThrowing?
I know it can be done using #Around, but around will be called on every hit of the url, that I do not want
What you want to do is Exception Handling on the controller. You don't need to build it yourself, Spring already supports you with some annotations like #ExceptionHandler and #ControllerAdvice. Best would be to follow this example: https://spring.io/blog/2013/11/01/exception-handling-in-spring-mvc#using-controlleradvice-classes
#ControllerAdvice
class GlobalControllerExceptionHandler {
#ResponseStatus(HttpStatus.CONFLICT) // 409
#ExceptionHandler(DataIntegrityViolationException.class)
public void handleConflict() {
// Nothing to do
}
}
#ControllerAdvice
class GlobalDefaultExceptionHandler {
public static final String DEFAULT_ERROR_VIEW = "error";
#ExceptionHandler(value = Exception.class)
public ModelAndView
defaultErrorHandler(HttpServletRequest req, Exception e) throws Exception {
// If the exception is annotated with #ResponseStatus rethrow it and let
// the framework handle it - like the OrderNotFoundException example
// at the start of this post.
// AnnotationUtils is a Spring Framework utility class.
if (AnnotationUtils.findAnnotation
(e.getClass(), ResponseStatus.class) != null)
throw e;
// Otherwise setup and send the user to a default error-view.
ModelAndView mav = new ModelAndView();
mav.addObject("exception", e);
mav.addObject("url", req.getRequestURL());
mav.setViewName(DEFAULT_ERROR_VIEW);
return mav;
}
}
You should use the fully qualified name of the class before method's name when you're referring to a pointcut. So, you should change #AfterThrowing something like this.
#AfterThrowing(pointcut="packageName.MyAspect.executionPointcut()",
throwing="th")
Please note that packageName is full package name of MyAspect.
I am trying to log the exception in the spring boot based web service.
So I have used GlobalExceptionHandler
My code :
#ControllerAdvice
#RestController
public class GlobalExceptionHandler {
#ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
#ExceptionHandler(value = Exception.class)
public String handleException(Exception e){
System.out.println("Ankit == "+e.getMessage());
StringWriter errors = new StringWriter();
e.printStackTrace(new PrintWriter(errors));
System.out.println(errors.toString());
return e.getMessage();
}
}
the code is working fine. What I want is exception details. I mean the code where the exception occurs? File name / line ? or do I have to parse the stacktrace? I mean spring boot must have thought something for this?
Using IDE
If you are using any IDE then go to Console Window.
Clear console
Repeat action that causes Exception
Search in Console (CTRL + F) for ERROR
Look for line above(Look for 2-3 lines if you don't find immediate above) the line which contains ERROR. This line has details of Class, Method where Exception has occurred.
Without looking at Console or Logs
If you want to use it in production then, handling atleast known exceptions(like BAD_REQUEST, NOT_FOUND etc.) the way it is done below might be helpful (adding an extra parameter to Exception Class) :
Employee employee = employeeService.getEmployeeById(employeeId);
if (null == employee) {
logger.error("No tenant exists for employeeId:"+employeeId);
throw new ObjectNotFoundException("Emplyee Not Found", this.getClass().getSimpleName();));
}
here this.getClass().getSimpleName(); will be passed as parameter from EmployeeController class. So in ObjectNotFoundException we can add a parameter ClassName and When you handle it in GlobalExceptionHandler, you can do it as it is done below,
#ControllerAdvice
#RestController
public class GlobalExceptionHandler {
#ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
#ExceptionHandler(value = Exception.class)
public String handleException(Exception e){
System.out.println("Ankit == "+e.getMessage());
StringWriter errors = new StringWriter();
e.printStackTrace(new PrintWriter(errors));
String classWithExceptionName = e.getClassName();
// you need to add this above getter method to your Exception Class
System.out.println(errors.toString());
return e.getMessage();
}
}
This is for known common exceptions. We need to add extra parameter(ClassName) to All Custom Exceptions that you are throwing and that might be little extra code but i think that is the way. Hope it helps now.
We have a (working) SOAP web service based on Spring WS with DefaultWsdl11Definition.
This is basically what it looks like:
#Endpoint("name")
public class OurEndpoint {
#PayloadRoot(namespace = "somenamespace", localPart = "localpart")
public void onMessage(#RequestPayload SomePojo pojo) {
// do stuff
}
}
It is wired in Spring and it is correctly processing all of our SOAP requests. The only problem is that the method returns a 202 Accepted. This is not what the caller wants, he'd rather have us return 204 No Content (or if that is not possible an empty 200 OK).
Our other endpoints have a valid response object, and do return 200 OK. It seems void causes 202 when 204 might be more appropriate?
Is it possible to change the response code in Spring WS? We can't seem to find the correct way to do this.
Things we tried and didn't work:
Changing the return type to:
HttpStatus.NO_CONTENT
org.w3c.dom.Element <- not accepted
Adding #ResponseStatus <- this is for MVC, not WS
Any ideas?
Instead of what I wrote in the comments it is possibly the easiest to create a delegation kind of solution.
public class DelegatingMessageDispatcher extends MessageDispatcher {
private final WebServiceMessageReceiver delegate;
public DelegatingMessageDispatcher(WebServiceMessageReceiver delegate) {
this.delegate = delegate;
}
public void receive(MessageContext messageContext) throws Exception {
this.delegate.receive(messageContext);
if (!messageContext.hasResponse()) {
TransportContext tc = TransportContextHolder.getTransportContext();
if (tc != null && tc.getConnection() instanceof HttpServletConnection) {
((HttpServletConnection) tc.getConnection()).getHttpServletResponse().setStatus(200);
}
}
}
}
Then you need to configure a bean named messageDispatcher which would wrap the default SoapMessageDispatcher.
#Bean
public MessageDispatcher messageDispatcher() {
return new DelegatingMessageDispatcher(soapMessageDispatcher());
}
#Bean
public MessageDispatcher soapMessageDispatcher() {
return new SoapMessageDispatcher();
}
Something like that should do the trick. Now when response is created (In the case of a void return type), the status as you want is send back to the client.
When finding a proper solutions we've encountered some ugly problems:
Creating custom adapters/interceptors is problematic because the handleResponse method isn't called by Spring when you don't have a response (void)
Manually setting the status code doesn't work because HttpServletConnection keeps a boolean statusCodeSet which doesn't get updated
But luckily we managed to get it working with the following changes:
/**
* If a web service has no response, this handler returns: 204 No Content
*/
public class NoContentInterceptor extends EndpointInterceptorAdapter {
#Override
public void afterCompletion(MessageContext messageContext, Object o, Exception e) throws Exception {
if (!messageContext.hasResponse()) {
TransportContext tc = TransportContextHolder.getTransportContext();
if (tc != null && tc.getConnection() instanceof HttpServletConnection) {
HttpServletConnection connection = ((HttpServletConnection) tc.getConnection());
// First we force the 'statusCodeSet' boolean to true:
connection.setFaultCode(null);
// Next we can set our custom status code:
connection.getHttpServletResponse().setStatus(204);
}
}
}
}
Next we need to register this interceptor, this can be easily done using Spring's XML:
<sws:interceptors>
<bean class="com.something.NoContentInterceptor"/>
</sws:interceptors>
A big thanks to #m-deinum for pointing us in the right direction!
To override the afterCompletion method really helped me out in the exact same situation. And for those who use code based Spring configuration, here´s how one can add the interceptor for a specific endpoint.
Annotate the custom interceptor with #Component, next register the custom interceptor to a WsConfigurerAdapter like this:
#EnableWs
#Configuration
public class EndpointConfig extends WsConfigurerAdapter {
/**
* Add our own interceptor for the specified WS endpoint.
* #param interceptors
*/
#Override
public void addInterceptors(List<EndpointInterceptor> interceptors) {
interceptors.add(new PayloadRootSmartSoapEndpointInterceptor(
new NoContentInterceptor(),
"NAMESPACE",
"LOCAL_PART"
));
}
}
NAMESPACE and LOCAL_PART should correspond to the endpoint.
If someone ever wanted to set custom HTTP status when returning non-void response, here is solution:
Spring Boot WS-Server - Custom Http Status
Is there a way to get the reason a HystrixCommand failed when using the #HystrixCommand annotation within a Spring Boot application? It looks like if you implement your own HystrixCommand, you have access to the getFailedExecutionException but how can you get access to this when using the annotation? I would like to be able to do different things in the fallback method based on the type of exception that occurred. Is this possible?
I saw a note about HystrixRequestContext.initializeContext() but the HystrixRequestContext doesn't give you access to anything, is there a different way to use that context to get access to the exceptions?
Simply add a Throwable parameter to the fallback method and it will receive the exception which the original command produced.
From https://github.com/Netflix/Hystrix/tree/master/hystrix-contrib/hystrix-javanica
#HystrixCommand(fallbackMethod = "fallback1")
User getUserById(String id) {
throw new RuntimeException("getUserById command failed");
}
#HystrixCommand(fallbackMethod = "fallback2")
User fallback1(String id, Throwable e) {
assert "getUserById command failed".equals(e.getMessage());
throw new RuntimeException("fallback1 failed");
}
I haven't found a way to get the exception with Annotations either, but creating my own Command worked for me like so:
public static class DemoCommand extends HystrixCommand<String> {
protected DemoCommand() {
super(HystrixCommandGroupKey.Factory.asKey("Demo"));
}
#Override
protected String run() throws Exception {
throw new RuntimeException("failed!");
}
#Override
protected String getFallback() {
System.out.println("Events (so far) in Fallback: " + getExecutionEvents());
return getFailedExecutionException().getMessage();
}
}
Hopefully this helps someone else as well.
As said in the documentation Hystrix-documentation getFallback() method will be thrown when:
Whenever a command execution fails: when an exception is thrown by construct() or run()
When the command is short-circuited because the circuit is open
When the command’s thread pool and queue or semaphore are at capacity
When the command has exceeded its timeout length.
So you can easily get what raised your fallback method called by assigning the the execution exception to a Throwable object.
Assuming your HystrixCommand returns a String
public class ExampleTask extends HystrixCommand<String> {
//Your class body
}
do as follows:
#Override
protected ErrorCodes getFallback() {
Throwable t = getExecutionException();
if (circuitBreaker.isOpen()) {
// Log or something
} else if (t instanceof RejectedExecutionException) {
// Log and get the threadpool name, could be useful
} else {
// Maybe something else happened
}
return "A default String"; // Avoid using any HTTP request or ypu will need to wrap it also in HystrixCommand
}
More info here
I couldn't find a way to obtain the exception with the annotations, but i found HystrixPlugins , with that you can register a HystrixCommandExecutionHook and you can get the exact exception in that like this :
HystrixPlugins.getInstance().registerCommandExecutionHook(new HystrixCommandExecutionHook() {
#Override
public <T> void onFallbackStart(final HystrixInvokable<T> commandInstance) {
}
});
The command instance is a GenericCommand.
Most of the time just using getFailedExecutionException().getMessage() gave me null values.
Exception errorFromThrowable = getExceptionFromThrowable(getExecutionException());
String errMessage = (errorFromThrowable != null) ? errorFromThrowable.getMessage()
this gives me better results all the time.
Is there a place where it is clearly documented that I cannot map UnsupportedMediaTypeException (because it's a rest easy exception and not custom application exception) using the javax.ws.rs.ext.ExceptionMapper?
I want to prove that to my client. Or another thing I would like to do is map this exception to a Response that can be fetched at the client to show the error. Right now when this exception is thrown it provides no information to the client as the application ends abruptly.
Any help would be appreciated.
Thanks
You can map this exception. Why not? Do you get an error?
This code should do the job
#Provider
public class EJBExceptionMapper implements ExceptionMapper<org.jboss.resteasy.spi.UnsupportedMediaTypeException>{
Response toResponse(org.jboss.resteasy.spi.UnsupportedMediaTypeException exception) {
return Response.status(415).build();
}
}
Don't forget to declare that provider in Spring configuration file.
If you want to provide more information to the client create class
#XmlRootElement
public class Error{
private String message;
//getter and setter for message field
}
and then you can
#Provider
public class EJBExceptionMapper implements ExceptionMapper<org.jboss.resteasy.spi.UnsupportedMediaTypeException>{
Response toResponse(org.jboss.resteasy.spi.UnsupportedMediaTypeException exception) {
Error error = new Error();
error.setMessage("Whatever message you want to send to user");
return Response.entity(error).status(415).build();
}
}
If you don't want to use Error entity simply pass a string to Response.entity() call.
If you want to catch whatever is thrown in you application create generic exception mapper:
#Provider
public class ThrowableMapper implements ExceptionMapper<Throwable> {
public Response toResponse(Throwable t) {
ErrorDTO errorDTO = new ErrorDTO(code);
return Response.status(500).build();
}
}