I've implemented custom annotation in my project, but implemented method argument resolver was never invoked.
Can someone help me with this issue?
My implementation:
Annotation
#Target(ElementType.PARAMETER)
#Retention(RetentionPolicy.RUNTIME)
#Documented
public #interface MyAnnotation {
String value();
}
Resolver
public class MyAnnotationResolver implements HandlerMethodArgumentResolver {
public boolean supportsParameter(MethodParameter parameter) {
System.out.println("supportsParameter invoked!");
return parameter.getParameterAnnotation(MyAnnotation.class) != null;
}
public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest,
WebDataBinderFactory binderFactory) throws Exception {
...
return "someString";
}
}
Configuaration
#Configuration
#EnableWebMvc
public class Config extends WebMvcConfigurerAdapter {
...
#Override
public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
argumentResolvers.add(new MyAnnotationResolver());
System.out.println("Resolver added!");
}
...
}
Controller
#Controller
#RequestMapping("/project")
public class ProjectController{
#RequestMapping(method = RequestMethod.GET, value= "/{hashCode}")
#ResponseBody
public String index(#MyAnnotation("hashCode") String hashCode, Model model) {
...
System.out.println(hashCode == null ? "HashCode=null" : "HashCode=" + hashCode);
}
As output I get:
Resolver added!
HashCode=null
Why supportsParameter(...) was never invoked?
It is not reproducible. supportsParameter gets called with the given code.
Since 3 years have passed after you asked, I checked the code that was used back then when you posted this question. However, the relevant code didn't change that much.
One possible explanation is that there was an argument resolver that supported the parameter, since it doesn't check another when it finds one.
Related
I'd like to return 404 when the response object is null for every response automatically in spring boot.
I need suggestions.
I don't want to check object in controller that it is null or not.
You need more than one Spring module to accomplish this. The basic steps are:
Declare an exception class that can be used to throw an exception when a repository method does not return an expected value.
Add a #ControllerAdvice that catches the custom exception and translates it into an HTTP 404 status code.
Add an AOP advice that intercepts return values of repository methods and raises the custom exception when it finds the values not matching expectations.
Step 1: Exception class
public class ResourceNotFoundException extends RuntimeException {}
Step 2: Controller advice
#ControllerAdvice
public class ResourceNotFoundExceptionHandler
{
#ExceptionHandler(ResourceNotFoundException.class)
#ResponseStatus(HttpStatus.NOT_FOUND)
public void handleResourceNotFound() {}
}
Step 3: AspectJ advice
#Aspect
#Component
public class InvalidRepositoryReturnValueAspect
{
#AfterReturning(pointcut = "execution(* org.example.data.*Repository+.findOne(..))", returning = "result")
public void intercept(final Object result)
{
if (result == null)
{
throw new ResourceNotFoundException();
}
}
}
A sample application is available on Github to demonstrate all of this in action. Use a REST client like Postman for Google Chrome to add some records. Then, attempting to fetch an existing record by its identifier will return the record correctly but attempting to fetch one by a non-existent identifier will return 404.
Simplest way to do this in Spring is write your own exception class like below
#ResponseStatus(value = HttpStatus.NOT_FOUND)
class ResourceNotFoundException extends RuntimeException{
}
Then just throw the ResourceNotFoundException from anywhere.
if (something == null) throw new ResourceNotFoundException();
For more -> Read
Similar to #manish's answer (https://stackoverflow.com/a/43891952/986160) but without the AspectJ pointcut and using another #ControllerAdvice instead:
Step 1: NotFoundException class:
public class NotFoundException extends RuntimeException {
public NotFoundException(String msg) {
super(msg);
}
public NotFoundException() {}
}
Step 2: Check if body returned in endpoint is null and throw NotFoundException:
#ControllerAdvice
public class NotFoundAdvice implements ResponseBodyAdvice {
#Override
public boolean supports(MethodParameter returnType, Class converterType) {
return true;
}
#Override
#SuppressWarnings("unchecked")
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {
if (body == null) {
throw new NotFoundException("resource not found");
}
return body;
}
}
Step 3: handle NotFoundException and make the response have a status of 404
#ControllerAdvice
public class GlobalExceptionAdvice {
#Data
public class ErrorDetails {
private Date timestamp;
private String message;
private String details;
public ErrorDetails(Date timestamp, String message, String details) {
super();
this.timestamp = timestamp;
this.message = message;
this.details = details;
}
}
#ExceptionHandler(NotFoundException.class)
public final ResponseEntity<ErrorDetails> notFoundHandler(Exception ex, WebRequest request) {
ErrorDetails errorDetails = new ErrorDetails(new Date(), ex.getMessage(),
request.getDescription(false));
return new ResponseEntity<>(errorDetails, HttpStatus.NOT_FOUND);
}
}
Alternative to Step 3:
You can just annotate your NotFoundException with #ResponseStatus and override fillInStackTrace() (from https://stackoverflow.com/a/31263942/986160) so that it has similar effect to GlobalExceptionAdvice and doesn't show stacktrace like this:
#ResponseStatus(value = HttpStatus.NOT_FOUND,reason = "resource not found")
public class NotFoundException extends RuntimeException {
public NotFoundException(String msg) {
super(msg);
}
public NotFoundException() {}
#Override
public synchronized Throwable fillInStackTrace() {
return this;
}
}
There is no need to throw exceptions, now ResponseBodyAdvice does the trick:
#ControllerAdvice
public class NullTo404 implements ResponseBodyAdvice<Object> {
#Override
public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
return true;
}
#Override
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType,
Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request,
ServerHttpResponse response) {
if (body == null) {
response.setStatusCode(HttpStatus.NOT_FOUND);
}
return body;
}
}
Similarly, you can implement ResponseBodyAdvice<Optional<?>>, and check for Optional.isEmpty() before setting the response status. It has the added benefit of working nicely with CrudRepository. Most controller methods eventually ends like this:
public Optional<Product> getProductBySku(#PathVariable String sku) {
// logic goes here...
return productRepository.findBySku(sku);
}
I would like to find a a way to validate a rest method based on all parameters outside the Controller.
First Question: Is there already a way to do it?
Second Question: If not - how can I hook the validation into spring mvc binding prozess.
A way how it could look like. It would be nice to mark the method with a new #MethodValidation Annotation:
#Validate
#MethodValidation(MyValidator.class)
public Response doSomthing(String param1, Integer param2, Something param3){}
Annotation
#Target({ElementType.METHOD})
#Retention(RetentionPolicy.RUNTIME)
#Documented
public #interface MethodValidation{
Class<? extends MethodValidator<?, ?>>[] value();
}
Implement a Validator
public class MyValidator implements MethodValidator{
public void validate(Object[] params, Errors errors){
String param1 = (String ) params[0];
Integer param2 = (Integer) params[1];
Something param3 = (Something)params[3];
// .... do some validations
if(error)
errors.reject("Some.error.done");
}
}
what kind of parameters exactly? a lot of spring stuff is actually available in ThreadLocals, if you dare to dig into it.
you CAN inject stuff into the binding process:
#ControllerAdvice
public class FooControllerAdvice {
#InitBinder
public void initBinder(WebDataBinder binder) {
binder.registerCustomEditor(
Date.class,
new CustomFooEditor()
);
}
}
and the actual editor:
public class CustomFooEditor extends PropertyEditorSupport {
}
but this doesn't give you that much of an edge over regular validation.
or you can use spring aop triggered by an annotation, then annotate your methods, with the config:
#EnableAspectJAutoProxy(proxyTargetClass=true)
an aspect:
#Aspect
#Component
public class ValidationAspect {
#Pointcut("execution(public * * (..))")
private void anyPublicMethod() {}
#Around("anyPublicMethod() && #annotation(foo)")
public Object all(
ProceedingJoinPoint proceedingJoinPoint,
Foo ann) throws Throwable {
}
[...]
}
an annotation:
#Inherited
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.METHOD)
public #interface Foo {
}
public String value();
and then annotating your method:
#RequestMapping...
#Foo(value="foo.bar.ValidatorClassname")
public Response x() {
}
... so you see, there's a lot of ways you can go. i'd really like to know what keeps you from using standard validation?
.rm
thanx for the answer.
I hope I am right: The standard validation outside the controller just allows me to to validate each method parameter separately.
I actually get into problems when the validation depends on 2 or more method parameter. This could be in following situation: Some thing is a part of an Object hierarchy:
public class Parent{
private Integer id;
private List<Something> childs;
...
}
public class Something{
private Integer id;
private String name;
...
}
The Constrain: it is not allowed that a Parent has 2 somethings in the list with the same name. For saving a new some thing I am calling the method.
#RequestMapping(
value = "/chargingstation/{parentId}",
method = RequestMethod.Post)
public Response doSomthing(
#PathVariable("parentId") Integer parentId,
Something param3)
Add the parentId to the Something-ModelOject was not an option.
So is there a way to handle this situation with the standard validation?
Spring mvc controller
#RequestMapping(method = RequestMethod.GET)
public Result<String> create(Date beginDate) {
//...
}
client call this api, beginDate parameter used long type
curl 'http://localhost:8080/foos?beginDate=1459657565000'
the response is
>Error 400 Bad Request
maybe spring mvc cannot convert long to date automatically, so I wrote a customer converter
public class LongToDateConverter implements Converter<Long, Date> {
#Override
public Date convert(Long source) {
if (source == null ) {
return null;
}
return new Date(source);
}
}
#Configuration
#EnableWebMvc
public class WebMvcContext extends WebMvcConfigurerAdapter {
#Override
public void addFormatters(FormatterRegistry registry) {
registry.addConverter(new LongToDateConverter());
}
}
then I call this api again, still the same error
Error 400 Bad Request
and set breakpoint in convert method , and found it did not step into this method, So why this converter do not work?
Then I changed it to POST method
#RequestMapping(method = RequestMethod.POST)
public Result<String> create(CouponModel model) {
}
CouponModel:
private Date useBeginDate;
Still Error 400 Bad Request
spring mvc
#ModelAttribute("classname"),
How to make the argument "classname" a dynamic one ?
Whatever comes from view can get appended there.
Instantiation of the command object is the only place where Spring needs to know a command class. However, you can override it with #ModelAttribute annotated method:
#RequestMapping(method = RequestMethod.POST)
public void show(HttpServletRequest request,
#ModelAttribute("objectToShow") Object objectToShow)
{
...
}
#ModelAttribute("objectToShow")
public Object createCommandObject() {
return getCommandClass().newInstance();
}
By the way, Spring also works fine with the real generics:
public abstract class GenericController<T> {
#RequestMapping("/edit")
public ModelAndView edit(#ModelAttribute("t") T t) { ... }
}
#Controller #RequestMapping("/foo")
public class FooController extends GenericController<Foo> { ... }
Using Spring 3.2.3, I'm trying to implement a simple CRUD controller that handles REST-ful URLs. It relies on a PropertyEditor to convert a path variable to a BusinessService entity by loading it from an application service. Code is as follows:
#Controller
public class BusinessServiceController {
#Autowired
private BusinessServiceService businessSvcService;
public BusinessServiceController() {
}
#InitBinder
public void initBinder(final WebDataBinder binder) {
binder.registerCustomEditor(BusinessService.class, new BusinessServicePropertyEditor(businessSvcService));
}
#RequestMapping(value = "/ui/account/business-services/{businessSvc}", method = RequestMethod.POST, consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE)
public ModelAndView update(#ModelAttribute("businessSvc") #Valid final BusinessService businessSvc, final BindingResult result,
final RedirectAttributes redirectAttribs) throws UnknownBusinessServiceException {
ModelAndView mav;
if (result.hasErrors()) {
mav = new ModelAndView("/business-service/edit");
}
else {
businessSvcService.updateBusinessService(XSecurity.principal().getId(), businessSvc);
mav = new ModelAndView("redirect:/ui/account/business-services");
redirectAttribs.addFlashAttribute("message", Message.info("businessService.updated", businessSvc.getTitle()));
}
return mav;
}
}
public class BusinessServicePropertyEditor extends PropertyEditorSupport {
private final BusinessServiceService businessSvcService;
public BusinessServicePropertyEditor(final BusinessServiceService businessSvcService) {
this.businessSvcService = businessSvcService;
}
#Override
public String getAsText() {
final BusinessService svc = (BusinessService) getValue();
return Long.toString(svc.getId());
}
#Override
public void setAsText(final String text) {
final BusinessService svc = businessSvcService.getBusinessService(Long.parseLong(text));
setValue(svc);
}
}
According to SPR-7608, starting from Spring 3.2, #ModelAttribute method argument resolution checks if a path variable by the same name exists (it does here), in which case it tries to convert that path variable's value to the target parameter type through registered Converters and PropertyEditors. This is not what I'm experiencing. When I inspect what ServletModelAttributeMethodProcessor does, it clearly uses the request DataBinder's ConversionService to perform type conversion, which does not consider registered PropertyEditors, and hence BusinessServicePropertyEditor#setAsText is never called.
Is this a configuration problem or an actual bug?
Thanks for your help!
Spring's ConversionService and Converters are replacement for standard Java Beans PropertyEditors.
You need to implement Converter instead of PropertyEditor if this feature is based purely on conversion service.
To register your custom converters in WebDataBinder you might use ConfigurableWebBindingInitializer or #InitBinder method.