#Transactional
public User getUser(String username) {
return userDAO.getUser(username);
}
I am using spring #Transactional annotation in my project.Now if transaction is rolled back i want to catch a notification so that i can show it to the user.How is it possible?
If the transaction fails, that indicates an exception was thrown. You will have to catch the Exception from the place (mostly the controller) where you are calling this method public User getUser(String username) and in the catch you can set some error code/ error message into the request and use it to display the message on UI.
Related
I have server which is built using SpringBoot and restful api's. It is simple CRUD application.
I am trying to check if email already exists while adding a new user.
I am not sure how to send error messages over rest api. I have tried like this:
UserController.java
//POST method for adding one user
#PostMapping("/addUser")
public ResponseEntity<User> addUser(#RequestBody User user){
User existingUser = userRepository.findByEmail(user.getEmail());
if(existingUser != null){
throw new UserAlreadyExistException("User with this email already exists");
}
return new ResponseEntity<>(service.saveUser(user), HttpStatus.OK) ;
}
UserAlreadyExistException.java
public class UserAlreadyExistException extends RuntimeException{
public UserAlreadyExistException(String message) {
super(message);
}
}
When I test it with Postman I get Error: 500 Internal Server Error
And in InteliJ I have this exception thrown:
com.example.library.UserAlreadyExistException: User with this email
already exists
Is this a correct way to do it or what is the best practice?
What you're looking for is #ControllerAdvice and #ExceptionHandler. The way such exceptions are handled is:
Create a global exception handler and annotate with #ControllerAdvice
Catch your exception using #ExceptionHandler in one of the methods specific to a certain exception.
So, adding below code will catch the exception and return custom response.
#ControllerAdvice
public class GlobalExceptionHandler {
#ExceptionHandler
public ResponseEntity<Object> handleAuthenticationException(UserAlreadyExistException e) {
// do what you want with e
return new ResponseEntity<>("User already exists", HttpStatus.OK);
}
How to redirect to login page if a specific exception is raised in JHipster?
There is a class in JHipster ExceptionTranslator which is used to handle the raised exceptions.
You can handle whatever exception you want to handle in the desired way.
#ExceptionHandler(MyException.class)
#ResponseStatus(HttpStatus.UNAUTHORIZED)
#ResponseBody
public String processJwtException(MyException ex) {
log.error("MyException occured : ", ex);
return "redirect:login_url";
}
My Spring Boot OAuth REST application returns "401 Unauthorized" status when the database connection failure(Spring Security throws InternalAuthenticationServiceException ).
It's strange, and I need to change status to "500 Internal server error" that client can provide some adequate description, like "service is not available".
If I use WebResponseExceptionTranslator then I can catch response, but if I change HTTP status, it works only when the database active. If the database is shutdown, then I get "401 Unauthorized" again.
How can I solve this problem most gracefully?
Depends on which level the exception is thrown, you might want to add exception handler to your login controller:
#ExceptionHandler(InternalAuthenticationServiceException.class)
public ModelAndView handleError(HttpServletRequest req, Exception ex) {
// convert exception to 500, add logging and
}
Learn more about exception handling here:
https://spring.io/blog/2013/11/01/exception-handling-in-spring-mvc
I fix this by adding "try catch" around jdbcTemplate request in my custom UserDetailService.
protected List<UserDetails> loadUsersByUsername(String username) {
try {
userDetailsList = this.getJdbcTemplate().query( USERS_BY_USERNAME, new String[]{username},
new RowMapper() {
public UserDetails mapRow( ResultSet rs, int rowNum ) throws SQLException {
String username = rs.getString( 1 );
/* etc. map user fields */
return new SecurityUser( username, /* other params... */ );
}
});
} catch (CannotGetJdbcConnectionException e){
logger.error( "UserDetailService SQL error: " + e.getMessage(), e );
}
return userDetailsList;
}
And then I check InternalAuthenticationServiceException
by WebResponseExceptionTranslator and change response status.
It seems that when I catch CannotGetJdbcConnectionException then something ruins in chain. It works, but I will leave my question open, maybe someone can offer a more clear solution.
In our application we are applying spring declarative transactions using annotations at service layer.
Here i am not getting any idea on how to handle exceptions properly.
What exactly my requirement is when dao layer throws any hibernate exception we are rolling back the transaction, but in one case i am getting InvalidDataAccessResourceUsageException because there is a unique index violation happening. So what i would like to do here is i want to catch InvalidDataAccessResourceUsageException exception at service class and have to rethrow the application specific exception to controller.
But whats happening here is as we have transaction demarcation at service layer class the session is flushing at service layer(ie when tx commits) after executing the method, as a result i cant catch it into the same method and it is directly propagating to the controller.
Please suggest me work around on this.
also seeking one more clarification, suppose i have a method like below
#Transactional(value="transactionManager",readOnly = false, propagation = Propagation.REQUIRED,rollbackFor = HibernateException.class)
public SomeDTO editObject(SomeDTO someDto, String user) throws EditException {
try{
/*
call to dao.edit();
another call to anotherDao.addEditsTOAnotherTable();
some business logic*/
} catch(HibernateException e){
} catch(InvalidDataAccessResourceUsageException ie){}
}
Can i catch exceptions as above. Note: I am not handling or throwing any exceptions from dao. Also there is no session cache mechanisms like FlushMode.ALWAYS etc at dao layer as it will flush during tx.commit().
By default #Transactional will rollback for any RuntimeException, and since HibernateException is a RuntimeException , roll back will be done automaticaly and you don't have to add rollbackFor = HibernateException.class
You can handle Exception this way:
try{
}catch(InvalidDataAccessResourceUsageException e){
throw new YourApplicationExceptionNotUniqueIndex();
}
and :
YourApplicationExceptionNotUniqueIndex shoud extends RuntimeException that way you wil have a rollback at your sevice layer and you can catch the exception at your Controller .
Better to handle check all the database constraints before editing into database
I've a service method called add() which is annotated with #Transactional.
I call it but when a ConstraintViolationException occurs inside corresponding DAO method it'll rollback the transaction even when I specify not to.
I expect that ConstraintViolationException to be caught and instead of it NotFoundException checked exception would be thrown.
#Override
#Transactional(noRollbackFor = ConstraintViolationException.class)
public User add(User user) throws NotFoundException {
try {
result = userDao.add(user);
} catch (RuntimeException e) {
throw new NotFoundException("Couldn't find group");
}
}
Is there a way to catch ConstraintViolationException without transaction rollback?
I'm using spring 3.1.1 and hibernate 3.6.
Ah, I see what happens. The ConstraintViolationException happens at commit time, after the method has been executed, when the transaction interceptor around your add() method tries to commit the transaction. Since it can't commit, obviously, the transaction is rollbacked. It can't to anything else.