I am developing REST API in Spring boot with Hibernate.
I have this function in my controller
#PostMapping("/profile")
public ResponseEntity<String> saveProfile(#Valid #RequestBody SaveProfileVM saveProfileVM,
BindingResult bindingResult)
throws JsonProcessingException {
if (bindingResult.hasErrors()) return super.fieldExceptionResponse(bindingResult);
Profile profile;
boolean optimisticLockException = true;
int retryCount = 0;
do {
try {
profile = accountService.saveProfile(saveProfileVM.getAccountId(),
saveProfileVM.getName(),
saveProfileVM.getEmail());
optimisticLockException = false;
retryCount++;
} catch (ObjectOptimisticLockingFailureException exception) {
retryCount++;
System.out.println(exception.getMessage());
}
} while (optimisticLockException && retryCount < MAX_OPTIMISTIC_LOCK_EXCEPTION_RETRY_COUNT);
return ResponseEntity.status(HttpStatus.OK).body(objectMapper.writeValueAsString(profile));
}
and MAX_OPTIMISTIC_LOCK_EXCEPTION_RETRY_COUNT is 3
I don't want to duplicate the do..while and try..catch blocks in every method where I need to check ObjectOptimisticLockingFailureException
do {
try{}
catch{}
} while()
Is there any way that I can pass accountService.saveProfile() to a general method that has the do..while and try..catch block so that I don't have to copy and paste the blocks to every method I need?
Every controller extends a BaseController so, it might be good to have the general method in BaseController?
#RestController
#RequestMapping("/account")
public class AccountController extends BaseController {
Can you guys give an idea please?
You can use spring-retry. More details
#Retryable(value = ObjectOptimisticLockingFailureException.class, maxAttempts = 3)
public void saveProfile(Long accountId, String name, String email){..}
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.
When I go to /confirmation-account link, in tomcat console I can see that if and else block is also executed. I can see:
print from ColorConsoleHelper.getGreenLog("loginView") and from ColorConsoleHelper.getGreenLog("confirmationAccountView")
This is really strange behavior. Why?
#RequestMapping(value = "/confirmation-account", method = RequestMethod.GET)
#Transactional
public ModelAndView displayConfirmationAccountPage(ModelAndView modelAndView, #RequestParam Map<String, String> requestParams) {
final int ACTIVE_USER = 1;
// find the user associated with the confirmation token
UserEntity userEntity = userService.findUserByConfirmationToken(requestParams.get("token"));
// this should always be non-null but we check just in case
if (userEntity!=null) {
// set the confirmation token to null so it cannot be used again
userEntity.setConfirmationToken(null);
// set enabled user
userEntity.setEnabled(ACTIVE_USER);
// save data: (token to null and active user)
saveAll(userEntity.getTrainings());
/*
RedirectAttributes won't work with ModelAndView but returning a string from the redirecting handler method works.
*/
modelAndView.addObject("successMessage", "Konto zostało pomyślnie aktywowane!");
modelAndView.setViewName("loginView");
ColorConsoleHelper.getGreenLog("loginView");
} else {
ColorConsoleHelper.getGreenLog("confirmationAccountView");
modelAndView.addObject("errorMessage", "Link jest nieprawidłowy...");
modelAndView.setViewName("confirmationAccountView");
}
return modelAndView;
}
public void saveAll(List<TrainingUserEntity> trainingUserEntityList) {
for ( TrainingUserEntity trainingUserEntity : trainingUserEntityList) {
entityManagerService.mergeUsingPersistenceUnitB(trainingUserEntity);
}
}
public void mergeUsingPersistenceUnitB(Object object) {
EntityManager entityManager = getEntityManagerPersistenceUnitB();
EntityTransaction tx = null;
try {
tx = entityManager.getTransaction();
tx.begin();
entityManager.merge(object);
tx.commit();
}
catch (RuntimeException e) {
if ( tx != null && tx.isActive() ) tx.rollback();
throw e; // or display error message
}
finally {
entityManager.close();
}
}
Below solution & explanation:
Because of /confirmation-account link is invoke twice, what is caused by dynamic proxy and #Transactional method annotated in controller It is mandatory to check how many displayConfirmationAccountPage method is invoked. It is workaround.
What do you think it is good or not to annotated #Transactional controller method?
I have normal #Controller and #RestController in one App.
How it possible to handle erros in Json for REST, and redirect to error page for normal #Controller?
You can make use of the Spring Annotation #ExceptionHandler in your controller and throw Exceptions in your controller logic. For an short example I will use Java's RuntimeException. You could define your own exception and throw them
// your controller classes
#Controller
public class MyController {
#ExceptionHanlder(RuntimeException.class)
public String errorInController(){
// for your custom page
return "yourDefineErrorTemplatePage";
// if you want to redirect to the default spring page
// return "redirect:/error";
}
#RequestMapping("yourFirstEndpoint")
public String getPage(){
if(yourLogicHere){
throw new RuntimeException("Display error page");
}
return "myPage";
}
}
Your #RestController could look like the following:
#RestController
public class RestControllerClass{
#ExceptionHandler(RuntimeException.class)
public ResponseEntity<Error> errorOccured(){
// you can return just a String or define your own 'error object'
Error error = new Error("Some error occured");
return new ResponseEntity<Error>(error, Http.Status.NOT_FOUND);
}
#RequestMapping("yourSecondEndpoint")
public ResponseEntity<YourEntity> getPage(){
// the entity you want do return as json
YourEntity yourEntity = new YourEntity();
if(yourLogicHere){
throw new RuntimeException("Display error page");
}
return new ResponseEntity<YourEntity>(yourEntity, HttpStatus.OK);
}
}
Example for the Error Object:
public class Error{
private String errorMessage;
public Error(String errorMessage){
this.errorMessage = errorMessage;
}
}
I hope this small example can solve your Problem.
For more details visit: https://spring.io/blog/2013/11/01/exception-handling-in-spring-mvc
I’m using DWR 3.0.0-rc2 and Spring 3.1.1.RELEASE. I was wondering if its possible to validate my #DataTransferObject input object using the Spring style “#Valid” (javax.validation.Valid) annotation. My specific question is, if this is possible and I set up my remote call like so …
#RemoteMethod
#Override
public String myRemoteMethod(#Valid final MyDto request)
{
how do I test to see if the input object (request) is valid and then throw a corresponding set of errors back to the client?
Thanks, - Dave
This looks like a good case to apply some AOP. One way is to create a #Before aspect that inspects the called arguments to see if they are annotated with #Valid, and if so trigger the validation for that argument and treat the results.
The code of this aspect would look like this:
#Aspect
public class ValidatingAspect {
Validator validator;
public ValidatingAspect() {
Configuration<?> configuration = Validation.byDefaultProvider().configure();
ValidatorFactory factory = configuration.buildValidatorFactory();
this.validator = factory.getValidator();
}
#Before("execution(* com.yourpackage..*.*(..))")
public void validateBefore(JoinPoint jp) throws Throwable {
Object[] args = jp.getArgs();
MethodSignature ms = (MethodSignature) jp.getSignature();
Method m = ms.getMethod();
Annotation[][] parameterAnnotations = m.getParameterAnnotations();
for (int i = 0; i < parameterAnnotations.length; i++) {
Annotation[] annotations = parameterAnnotations[i];
for (Annotation annotation : annotations) {
if (annotation.annotationType() == Valid.class) {
Set<ConstraintViolation<T>> constraintViolations = validator.validate(jp.getArgs()[i]);
... handle validation results ...
}
}
}
}
}
Suppose I have a Website that is used in normal mode (browser) and in some other mode, like a MobileView mode (inside a mobile app). For each Controller I create, there might be correspondent controller for MobileView, processing the same url.
The easiest solution is to create ifs in all the Controllers that have MobileView logic. Another solution would be to use a correspondent url for MobileView (similar to the normal url) and two separate Controllers (possible where one extends from another; or use some other way to recycle common code)
But, a more elegant solution would be to have some extra annotations, like #SupportsMobileView (to mark a controller, and tell the app that this will have a correspondent MobileView Controller) and #MobileViewController (to mark a second controller, and tell the app that this controller needs to run immediately after the initial controller marked with #SupportsMobileView). The link between a normal controller and a MobileView controller would be through the url they process (defined with #RequestMapping).
Is it possible to extend Spring MVC (A)? Where to inject new annotation scanners (B) and annotation handlers / component handlers (C)? How should the MobileView controller be executed (D) (right now I am thinking that it could be executed through AOP, where the new handler of my new controller type programatically creates a Join-Point on the corresponding normal controller)
Note that I did not mention how this MobileView mode is triggered and detected. Let's just say that there a Session boolean variable (flag) for that.
Critics on any points (A), (B), (C) or (D) are welcomed, as well as technical hints and alternative solution to any point or the whole solution.
HandlerInterceptor can be used to intercept the RequestMapping handling. This is a simple example how to configure and implement one.
You can check for your session variable and will have a bunch of methods that will allow you to do custom processing or just exchange the view from the normal controller handling with your mobile view.
Ok, warnings:
this is only a proof of concept of what I understood must be done so:
+#MobileViewEnable and #MobileView annotated (and related) methods need to stay in the same controller
+there's no check for the httpAction used
+the two methods must have the same signature
+mobileView annotation value and requestMapping annotation value must be equals and uniques
+the logic inside callYourLogic(..) defines which method is going to be called, at the moment there's a very simple logic that check if exist the parameter ("mobile") in the request, just to test
+this code is not intended to be used as is (at all)
+don't know if it works at all outside my pc (joke :D, ehm..)
SO:
Annotations:
#Retention(RetentionPolicy.RUNTIME)
public #interface MobileView {
String value() default "";
}
#Retention(RetentionPolicy.RUNTIME)
public #interface MobileViewEnable {
}
ExampleController:
#Controller
public class MainController extends BaseController {
private final static Logger logger = LoggerFactory.getLogger(MainController.class);
private final static String PROVA_ROUTE = "prova";
#MobileViewEnable
#RequestMapping(PROVA_ROUTE)
public String prova() {
logger.debug("inside prova!!!");
return "provaview";
}
#MobileView(PROVA_ROUTE)
public String prova2() {
logger.debug("inside prova2!!!");
return "prova2view";
}
}
Aspect definition:
<bean id="viewAspect" class="xxx.yyy.ViewAspect" />
<aop:config>
<aop:pointcut expression="#annotation(xxx.yyy.MobileViewEnable)" id="viewAspectPointcut" />
<aop:aspect ref="viewAspect" order="1">
<aop:around method="around" pointcut-ref="viewAspectPointcut" arg-names="viewAspectPointcut"/>
</aop:aspect>
</aop:config>
Aspect implementation:
public class ViewAspect implements BeforeAdvice, ApplicationContextAware {
private final static Logger logger = LoggerFactory.getLogger(ViewAspect.class);
private ApplicationContext applicationContext;
public Object around(ProceedingJoinPoint joinPoint) {
Method mobileViewAnnotatedMethod = null;
HttpServletRequest request = getCurrentHttpRequest();
String controllerName = getSimpleClassNameWithFirstLetterLowercase(joinPoint);
Object[] interceptedMethodArgs = getInterceptedMethodArgs(joinPoint);
String methodName = getCurrentMethodName(joinPoint);
Method[] methods = getAllControllerMethods(joinPoint);
Method interceptedMethod = getInterceptedMethod(methods, methodName);
String interceptedMethodRoute = getRouteFromInterceptedMethod(interceptedMethod);
if (callYourLogic(request)) {
mobileViewAnnotatedMethod = getMobileViewAnnotatedMethodWithRouteName(methods, interceptedMethodRoute);
if (mobileViewAnnotatedMethod != null)
return invokeMethod(mobileViewAnnotatedMethod, interceptedMethodArgs, controllerName);
}
return continueInterceptedMethodExecution(joinPoint, interceptedMethodArgs);
}
private Object continueInterceptedMethodExecution(ProceedingJoinPoint joinPoint, Object[] interceptedMethodArgs) {
try {
return joinPoint.proceed(interceptedMethodArgs);
} catch (Throwable e) {
logger.error("unable to proceed with intercepted method call: " + e);
}
return null;
}
private Object[] getInterceptedMethodArgs(JoinPoint joinPoint) {
return joinPoint.getArgs();
}
private boolean callYourLogic(HttpServletRequest request) {
// INSERT HERE YOUR CUSTOM LOGIC (e.g.: is the server accessed from a mobile device?)
// THIS IS A STUPID LOGIC USED ONLY FOR EXAMPLE
return request.getParameter("mobile")!= null;
}
private HttpServletRequest getCurrentHttpRequest() {
return ((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest();
}
private String invokeMethod(Method method, Object[] methodArgs, String className) {
if (method != null) {
try {
Object classInstance = getInstanceOfClass(method, className);
return (String) method.invoke(classInstance, methodArgs);
} catch (Exception e) {
logger.error("unable to invoke method" + method + " - " + e);
}
}
return null;
}
private Object getInstanceOfClass(Method method, String className) {
return applicationContext.getBean(className);
}
private Method getMobileViewAnnotatedMethodWithRouteName(Method[] methods, String routeName) {
for (Method m : methods) {
MobileView mobileViewAnnotation = m.getAnnotation(MobileView.class);
if (mobileViewAnnotation != null && mobileViewAnnotation.value().equals(routeName))
return m;
}
return null;
}
private String getRouteFromInterceptedMethod(Method method) {
RequestMapping requestMappingAnnotation = method.getAnnotation(RequestMapping.class);
if (requestMappingAnnotation != null)
return requestMappingAnnotation.value()[0];
return null;
}
private String getCurrentMethodName(JoinPoint joinPoint) {
return joinPoint.getSignature().getName();
}
private Method[] getAllControllerMethods(JoinPoint joinPoint) {
return joinPoint.getThis().getClass().getSuperclass().getMethods();
}
private String getSimpleClassNameWithFirstLetterLowercase(JoinPoint joinPoint) {
String simpleClassName = joinPoint.getThis().getClass().getSuperclass().getSimpleName();
return setFirstLetterLowercase(simpleClassName);
}
private String setFirstLetterLowercase(String simpleClassName) {
String firstLetterOfTheString = simpleClassName.substring(0, 1).toLowerCase();
String restOfTheString = simpleClassName.substring(1);
return firstLetterOfTheString + restOfTheString;
}
private Method getInterceptedMethod(Method[] methods, String lookingForMethodName) {
for (Method m : methods)
if (m.getName().equals(lookingForMethodName))
return m;
return null;
}
#Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}
}