I am using Spring & JPA with Hiberate as vendor.
In DAO layer I am trying to persist entity. If duplicate exists, it throws ConstraintViolationException of Hibernate. I have written try-catch in DAO for catching the exception but it does't go to catch block at all and throws Exception to service layer.
Does JPA allow to catch JDBCException in DAO layer or it'll directly throw it to upper layer?
My code looks like as follows :
public void saveEntity(SomeEntity entity) throws CustomException {
try {
... do something...
entityManager.persist(entity);
}catch(Exception e) {
throw new CustomException(e.getMessage());
}
}
Here If something happens before persist it catches but if something goes wrong while persisting and JDBCException comes it doesn't.
I know that I could have avoided this situation by checking first that if record exists and if not, only then I'll save. But I want to know why JDBCException (or any database related exceptions) exceptions are not getting caught here.
Any help appreciated.
I have found the reason for this.
The catch block in the DAO class is not able to catch exception because transaction commit is happening after method getting executed and so the method on which I have put #Transactional (service layer method) is catching the exception instead.
Here if I use flush() right after persist, it tries to commit right there and throws Exception which will get caught.
public void saveEntity(SomeEntity entity) throws CustomException {
try {
... do something...
entityManager.persist(entity);
entityManager.flush(); //tries to commit here & throws ConstraintViolationException if already exists
}catch(Exception e) {
throw new CustomException(e.getMessage());
}
}
Related
I am working on spring rest api and I would like to sure everything is working fine. I would like to log abnormal behaviors database connection error among others, I'm working with couchbase database and I'm getting in the endpoint response for example for this kind of exception: CouchbaseQueryExecutionException the next message: Unable to execute query due to the following n1ql errors: \n{\"msg\":\"No index available on keyspace kids_club that matches your query. Use CREATE INDEX or CREATE PRIMARY INDEX to create an index, or check that your expected index is online.\",\"code\":4000} and a very long trace.
For this i found a solution on internet that is extend ResponseEntityExceptionHandler and override handleExceptionInternal method like this:
#ControllerAdvice
public class RestExceptionHandler extends ResponseEntityExceptionHandler {
private static String DEFAULT_VALIDATION_ERROR_CODE = "KC-0020";
#ExceptionHandler(MiddlewareException.class)
protected ResponseEntity<ResponseBody> handleKidsClubException(MiddlewareException ex) {
return buildErrorResponse(HttpStatus.valueOf(ex.getHttpStatus()), ex.toError());
}
#ExceptionHandler(ServiceUnavailableException.class)
protected ResponseEntity<ResponseBody> handleServiceUnavailable(ServiceUnavailableException ex) {
return buildErrorResponse(INTERNAL_SERVER_ERROR, ex);
}
#ExceptionHandler(NoSuchElementException.class)
protected ResponseEntity<ResponseBody> handleNoFoundElement(NoSuchElementException ex) {
return buildErrorResponse(NOT_FOUND, ex);
}
#ExceptionHandler(CouchbaseQueryExecutionException.class)
protected ResponseEntity<ResponseBody> handleCouchbaseQueryException(ConstraintViolationException ex) {
return buildErrorResponse(BAD_REQUEST, ex);
}
}
But I'm not able to catch any kind of Internal Server Error in this way.
It seems like spring is handle and building the final message to the user.
Any ideas to resolve this?
Thanks.
#ExceptionHandler(NullPointerException.class)
public final ResponseEntity<Object> handleNullPointerException(NullPointerException ex, WebRequest request) {
LOGGER.info("Entering into the handleAllException method");
System.out.println("Exception is : " + ex.getClass());
ResponseData error = new ResponseData();
error.setRespCode(HttpStatus.NOT_FOUND.toString());
error.setRespMessage(ex.getLocalizedMessage());
error.setTimestamp(LocalDateTime.now());
return new ResponseEntity(error, HttpStatus.INTERNAL_SERVER_ERROR);
}
please try this way below to check whether you are able to catch exception or not.. From the sysout you will get the exact exception. Then you can use that exception to catch any particular exception from that business logic..
I have a Spring Boot REST application that uses ControllerAdvice and ExceptionHandlers. I'm using Jackson as my serialization/deserialization. I'm using PostMan as my client and when I send in different errors such as invalid inputs, bad JSON syntax etc... Jackson throws certain exceptions. Currently, I have an (1) ExceptionHandler that explicitly states each type of exception such as MismatchedInputException, InvalidFormatException, InvalidDentinitionException...these are all forms of JsonProcsessingException.
Is there a way to just catch JsonProcessingException and all its children? I return different messages/status codes depending on the types of exceptions. So if exception related to serialization is thrown I want a certain error message sent back.
You should create this method in #ControllerAdvice class and verify what exceptions you want to manage in order to return different messages/status codes .
#ExceptionHandler({InvalidFormatException.class, MismatchedInputException.class})
public void handlerIllegalArgumentException(JsonProcessingException exception,
ServletWebRequest webRequest) throws IOException {
if(exception instanceof InvalidFormatException) {
LOGGER.error(exception.getMessage(), exception);
webRequest.getResponse().sendError(HttpStatus.CONFLICT.value(), exception.getMessage());
} else if (exception instanceof MismatchedInputException) {
LOGGER.error(exception.getMessage(), exception);
webRequest.getResponse().sendError(HttpStatus.BAD_REQUEST.value(), exception.getMessage());
}
}
I'm implementing web application based on Spring MVC and organized around DDD concepts. Currently I try to implement ticket reservation functionality. The customer can see number of tickets available for the particular event. Then, he can enter number of tickets to be reserved and submit form. Request is received by controller which calls application service responsible for registration. Application service logic is as follows:
Validate incoming parameters:
1A. Check if event with the given ID exists
1B. Check if number of tickets available allows for reservation
If validation passed, proceed with registration; otherwise, report an error.
I have some doubts about the proper way for reporting validation errors - especially for point 1B. Situation when number of tickets does not allow for reservation is not something very unusual. Customer can see number of tickets that is not fully synchronized with current number of tickets in database (eventual consistency) - some other person could reserve some tickets in the meantime.
Initially I was thinking about reporting this problems by throwing some specific exceptions. However, I can think of couple of other problematic situations and having one exception for each on of them doesn't sound very well.
The other option I was considering was throwing one type of exception containing error code. However, I don't know how to handle this situation in Spring MVC properly.
What are the best practices for such problems? How do you deal with them in your MVC applications? Any advices greatly appreciated.
I think these are business constraint brokens that cannot be recovered.
My current solution is Exception hierachy.
public abstract class UncheckedApplicationException extends RuntimeException {
//omitted factory methods and constructors
public abstract String getStatusCode();
public abstract String getI18nCode();//ignore this if you don't need i18n
public abstract String[] getI18nArgs();//ignore this if you don't need i18n
}
Any custom exception extends this one. I think this could avoid code like this:
try {
//invoke your application service
} catch (InsufficientInventoryException e) {
statusCode = INSUFFICIENT_INVENTORY;
} catch (ExpriedPriceException e) {
statusCode = EXPIRED_PRICE;
} catch (NoSuchProductException e) {
statusCode = NO_SUCH_PRODUCT;
} catch (Exception e) {
statusCode = UNKNOWN;
}
Controller code snippet:
try {
//invoke your application service here
statusCode = SUCCESS;
message = messageSource.getSuccess(locale));
} catch (UncheckedApplicationException e) {
statusCode = e.getStatusCode();
message = messageSource.getMessage(e, locale));
} catch (Exception e) {
statusCode = UNKNOWN;
message = messageSource.getUnknownError(e, locale));
}
//add statusCode & message to modelAttribute
You can use #ExceptionHandler to reduce boilerplate try-catch code if your Controller is well organized(but pretty difficult).
The other reason to use Excepton is that application service is often used to delimit transaction boundary. An exception has to be thrown if you want to rollback.
I'm migrating some servlets over to the Spring framework, using Spring MVC. Currently in each servlet we authenticate the user and if the authentication fails we do this:
if (authfailed)
{
response.sendError(HttpServletResponse.SC_UNAUTHORIZED,
"You are not authorized.");
return;
}
On the front end is a YUI-based application, and when an error status is returned the "failure" callback displays a dialog with the error message given above.
I know in my controller I can get the response object and call sendError, but is that the best way to handle this? sendError also throws an IOException so I'd have to catch that - a bit of annoying code to insert in every method of every controller.
I have the same problem handling exceptions - the servlets have try-catch blocks that call sendError in the catch method. I know I can mark my exception handlers with
#ExceptionHandler
#ResponseStatus(value = HttpStatus.NOT_FOUND)
but doesn't the exception handling class need to be in each controller class?
Finally, if the exception happens in a service called from a controller, does the exception bubble up to the controller or should I handle the exception in the service (thus pushing these exception handling issues into the service layer)?
This seems more difficult than it should be, but as with many things in Spring it's likely I don't understand what's going on. All I want to do is to send an error status and message back in the response!
Thanks,
Paul
It looks like you have the most of the answers in your question itself :)
To reiterate,
Have the controller like this
#RequestMapping("/test")
public String verifyAuth(HttpServletRequest request) throws NotFoundException {
String id = request.getParameter("id");
if (id == null)
throw new NotFoundException("Id not found in the request");
return "success";
}
Declare the exception class in NotFoundException.java,
#ResponseStatus(value=HttpStatus.NOT_FOUND, reason="Id Not Found")
public class NotFoundException extends Exception {
public NotFoundException(String msg) {
super(msg);
}
}
This exception class need not be every controller class. Declare it as public class and import it in every required controller.
This is one way of doing it. If you like the non-spring style, declare HttpServletResponse in every controller arguments and do
#RequestMapping("/test")
public String verifyAuth(HttpServletRequest request, HttpServletResponse response) {
...
try {
response.sendError(..)
catch(..) {}
}
Or you can use views to show error message,
#RequestMapping("/test")
public String verifyAuth(HttpServletRequest request, Map<String, Object> map){
String id = request.getParameter("id");
if (id == null) {
map.put("status", HttpStatus.NOTFOUND);
map.put("reason", "Id Not Found");
return "error"
}
return "success";
}
Make sure your viewResolver is configured correctly and in the error.jsp to get the error string, you could say.
<body>
${status} ${reason}
</body>
Define error.jsp with nice css for all kind of errors you would expect.
These are not the only ways. With spring you have freedom to do anything. I have seen few ppl rendering json object for error message.
To answer your another question of if the error happens in the service called by the controller is depend on your scenario. For example you are trying to read the user store, if the user store not available error happens, I would handle there itself to read from another replica user store if one available and If I found user does not exist I would leave the exception to the controller to throw.
I've implemented a wrapper method around Elmah's Error Signaling, where a raised exception is only seen by Elmah for logging and mailing, but now I'd like to filter only these signalled exceptions out of the mailing, but still log them. How can I do this?
This is my simple wrapper:
public void LogException(Exception exception)
{
ErrorSignal.FromContext(HttpContext.Current).Raise(exception);
}
I've thought of wrapping the input exception in a custom SignalledException, and filtering those out of mailing, but then my logs get full of SignalledExceptions, and not the real exceptions.
Any other ideas please?
Elmah filtering works mainly on exception types. Programmatic filtering would allow me to examine information added to an exception, but I have yet to come across an Exception type with an ElmahFilteringData property, and I prefer not to 'invade' the exceptions I want logged. Here is how I accomplished only sending email notificatins for certain signalled exceptions:
First I have a special wrapper exception, purely for telling Elmah not to send an email notification for exceptions of this type:
public class ElmahEMailBlockWrapperException: Exception
{
public const string Explanation = "This is a wrapper exception that will be blocked by Elmah email filtering. The real exception is the InnerException";
public ElmahEMailBlockWrapperException(Exception wrappedException):base(Explanation, wrappedException) {}
}
Then, when I raise an exception I normally only want logged and not emailed, but maybe sometimes emailed, I use this code in my exception logging service:
public void LogException(Exception exception, bool includeEmail)
{
if (includeEmail)
{
ErrorSignal.FromContext(HttpContext.Current).Raise(exception);
}
else
{
// Wrap the input exception in a special exception type that the Elmah email filter can block.
var wrappedException = new ElmahEMailBlockWrapperException(exception);
ErrorSignal.FromContext(HttpContext.Current).Raise(wrappedException);
}
}
Now, in the Elmah filter events in Global.asax, I unwrap the exception to log it, and if it is wrapped, dismiss it from the email notification pipeline:
public void ErrorLog_Filtering(object sender, ExceptionFilterEventArgs e)
{
// If the exception was wrapped in a ElmahEMailBlockWrapperException exception to be blocked by the ErrorMail filter, the InnerException
// of the the ElmahEMailBlockWrapperException is the real exception to be logged, so we extract it, log it, and dismiss the wrapper.
var ebw = e.Exception.GetBaseException() as ElmahEMailBlockWrapperException;
if (ebw != null)
{
ErrorLog.GetDefault(HttpContext.Current).Log(new Error(ebw.InnerException));
e.Dismiss();
}
}
public void ErrorMail_Filtering(object sender, ExceptionFilterEventArgs e)
{
// If the exception was wrapped, i.e. raised only to be logged by Elmah and not emailed, dismiss it.
if (e.Exception.GetBaseException() is ElmahEMailBlockWrapperException)
{
e.Dismiss();
}
}