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Value cannot injected into service class spring boot

I already try to search through stackoverflow, and I don't think I find the solution I want...
Also I try to use answer https://stackoverflow.com/questions/45970442/spring-boot-value-returning-null and still doesn't work...
Here is my controller class
package com.vincent.springoauth.controller;
import com.vincent.springoauth.model.GiftCardRequest;
import com.vincent.springoauth.model.GiftCardResponse;
import com.vincent.springoauth.service.InCommGiftCardServiceImpl;
import org.springframework.web.bind.annotation.*;
#RestController
#RequestMapping("/api/gift-card")
public class GiftCardController{
#PostMapping("/activate")
public #ResponseBody
GiftCardResponse activate(GiftCardRequest request) {
GiftCardServiceImpl giftCardService = new GiftCardServiceImpl("");
return giftCardService.activate(request);
}
}
And here is my service class
package com.vincent.springoauth.service;
import com.vincent.springoauth.model.GiftCardRequest;
import com.vincent.springoauth.model.GiftCardResponse;
import lombok.extern.log4j.Log4j2;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
#Service
#Log4j2
public class GiftCardServiceImpl {
private final String baseEndpoint;
public GiftCardServiceImpl( #Value("${webserviceurl}")String baseEndpoint){
this.baseEndpoint = baseEndpoint;
}
public String accessToken() {
log.info("Access oauth token url address: " + baseEndpoint);
// will be use that base endpoint to manipulate stuff later
return "abcdefg";
}
public GiftCardResponse activate(GiftCardRequest request) {
log.info("Calling token ...");
accessToken();
log.info("Incomm Pre Auth Service");
// Generate preAuth request;
//RetailTransactionGenericRequestWrapper retailTransactionGenericRequest = buildRequest(request);
//log.info("RetailTransactionGenericRequest: " + retailTransactionGenericRequest);
GiftCardResponse response = GiftCardResponse.builder().responseCode("0").responseMessage("Success").build();
return response;
}
}
And in my application.properties I have following line webserviceurl=https://localhost/giftcard
The issue that in my service class the webserviceurl return null. How can I fix this?

In your controller you are creating your own instance of the service and so Spring is unaware of it and cannot inject the value. Your service class is annotated as a Service so Spring will create an instance, which will have the value injected but that is not the instance that your controller is using.
Instead you should declare that service as an instance variable in your controller and use either Autowire annotation on that instance variable or use constructor autowiring to ensure that the bean created by Spring is the one that is used by your controller.
#RestController
#RequestMapping("/api/gift-card")
public class GiftCardController{
private GiftCardServiceImpl giftCardService;
#Autowired
public GiftCardController(GiftCardServiceImpl giftCardService) {
this.giftCardService = giftCardService;
}

#Value annotation uses for injecting values into fields in Spring-managed beans. In your example, you create GiftCardServiceImpl on your own and Spring cannot control the creation and inject the webserviceurl value from application.properties. You can change GiftCardController to allow Spring to do this.
package com.vincent.springoauth.controller;
import com.vincent.springoauth.model.GiftCardRequest;
import com.vincent.springoauth.model.GiftCardResponse;
import com.vincent.springoauth.service.InCommGiftCardServiceImpl;
import org.springframework.web.bind.annotation.*;
#RestController
#RequestMapping("/api/gift-card")
public class GiftCardController{
private final GiftCardServiceImpl giftCardService;
public GiftCardController(GiftCardServiceImpl giftCardService) {
this.giftCardService = giftCardService;
}
#PostMapping("/activate")
public #ResponseBody
GiftCardResponse activate(GiftCardRequest request) {
return giftCardService.activate(request);
}
}

Try to inject GiftCardServiceImpl via Spring DI like in the example below
package com.vincent.springoauth.controller;
import com.vincent.springoauth.model.GiftCardRequest;
import com.vincent.springoauth.model.GiftCardResponse;
import com.vincent.springoauth.service.InCommGiftCardServiceImpl;
import org.springframework.web.bind.annotation.*;
#RestController
#RequestMapping("/api/gift-card")
public class GiftCardController{
#Autowired
private GiftCardServiceImpl giftCardService;
#PostMapping("/activate")
public #ResponseBody
GiftCardResponse activate(GiftCardRequest request) {
return giftCardService.activate(request);
}
}
The #Value annotation only works for Spring Beans, when you create the class via simple new keyword. Spring doesn't catch that should inject property in the constructor.

MethodValidationInterceptor and #Validated #ModelAttribute

I have a Spring Boot 2 app and I want to be able to validate controller arguments with Hibernate validator - which I'm using successfully. I have all my controller annotated as #Validated and I'm using the validation for request parameters like so #PathVariable #AssertUuid final String customerId - so far so good, everything works.
But, I want to also be able to validate #ModelAttribute from forms.
#Controller
#PreAuthorize("hasRole('ADMIN')")
#RequestMapping(path = "/customers")
#Validated
public class CustomerController
{
private final CustomerFacade customerFacade;
public CustomerController(
final CustomerFacade customerFacade
)
{
this.customerFacade = customerFacade;
}
#GetMapping("/create")
public ModelAndView create(
final AccessToken accessToken
)
{
return new ModelAndView("customer/create")
.addObject("customer", new CreateCustomerRequest());
}
#PostMapping("/create")
public ModelAndView handleCreate(
final AccessToken accessToken,
#Validated #ModelAttribute("customer") final CreateCustomerRequest customerValues,
final BindingResult validation
) throws
UserDoesNotHaveAdminAccessException
{
if (validation.hasErrors()) {
return new ModelAndView("customer/create")
.addObject("customer", customerValues);
}
CustomerResult newCustomer = customerFacade.createCustomer(
accessToken,
customerValues.getName()
);
return new ModelAndView(new RedirectView("..."));
}
public static final class CreateCustomerRequest
{
#NotNull
#NotBlank
private String name;
public CreateCustomerRequest(final String name)
{
this.name = name;
}
public CreateCustomerRequest()
{
}
public String getName()
{
return name;
}
}
}
But this causes the MethodValidationInterceptor to throw ConstraintViolationException when I send invalid data. This would normally make sense and I want this behaviour in every other case, but in this case, as you can see, I want to use the BindingResult to handle the validation errors - which is neccesary when working with forms.
Is there a way I could tell Spring to not validate this particular parameter with MethodValidationInterceptor, because it's already validated by the binder and I want to handle it differently?
I've been digging around in the spring code and it looks like is not designed to work together. I have the some ideas how to fix this:
remove the #Validated from the argument and
call validator.validate() explicitly in the controller method - ugly and dangerous (you might forget to call it)
create another AOP interceptor, that would find "pairs" of #ModelAttribute and BindingResult and call the validator there, forcing the validation globally
Am I going about this completely wrong? Am I missing something? Is there a better way?

I've come up with a solution that allows me to continue working, but I don't consider this problem solved.
As I've hinted in the original question, this Aspect forces validation of the #ModelAttribute when it isn't annotated with #Validated or #Valid.
This means that the ConstraintViolationException is not thrown for invalid #ModelAttribute and you can handle the errors in method body.
import com.google.common.collect.Iterators;
import com.google.common.collect.PeekingIterator;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.core.MethodParameter;
import org.springframework.validation.Errors;
import org.springframework.validation.Validator;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.ModelAttribute;
import javax.validation.Valid;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
#SuppressWarnings({"checkstyle:IllegalThrows"})
#Aspect
public class ControllerModelAttributeAutoValidatingAspect
{
private final Validator validator;
public ControllerModelAttributeAutoValidatingAspect(
final Validator validator
)
{
this.validator = validator;
}
#Around("execution(public * ((#org.springframework.web.bind.annotation.RequestMapping *)+).*(..)))")
public Object proceed(final ProceedingJoinPoint pjp) throws Throwable
{
MethodSignature methodSignature = MethodSignature.class.cast(pjp.getSignature());
List<MethodParameter> methodParameters = getMethodParameters(methodSignature);
PeekingIterator<MethodParameter> parametersIterator = Iterators.peekingIterator(methodParameters.iterator());
while (parametersIterator.hasNext()) {
MethodParameter parameter = parametersIterator.next();
if (!parameter.hasParameterAnnotation(ModelAttribute.class)) {
// process only ModelAttribute arguments
continue;
}
if (parameter.hasParameterAnnotation(Validated.class) || parameter.hasParameterAnnotation(Valid.class)) {
// if the argument is annotated as validated, the binder already validated it
continue;
}
MethodParameter nextParameter = parametersIterator.peek();
if (!Errors.class.isAssignableFrom(nextParameter.getParameterType())) {
// the Errors argument has to be right after the ModelAttribute argument to form a pair
continue;
}
Object target = pjp.getArgs()[methodParameters.indexOf(parameter)];
Errors errors = Errors.class.cast(pjp.getArgs()[methodParameters.indexOf(nextParameter)]);
validator.validate(target, errors);
}
return pjp.proceed();
}
private List<MethodParameter> getMethodParameters(final MethodSignature methodSignature)
{
return IntStream.range(0, methodSignature.getParameterNames().length)
.mapToObj(i -> new MethodParameter(methodSignature.getMethod(), i))
.collect(Collectors.toList());
}
}
Now you can just keep using validation annotations in your controller methods as you're used to, and at the same time, the final BindingResult validation works as expected.
#PostMapping("/create")
public ModelAndView handleCreate(
final AccessToken accessToken,
#ModelAttribute("customer") final CreateCustomerRequest customerValues,
final BindingResult validation
)

Thank you for sharing this solution.
I used it as inspiration and as a base for creating a more general method arguments validator that I intend to use on selected methods.
Validation is triggered for methods annotated by #Validate:
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
#Target(ElementType.METHOD)
#Retention(RetentionPolicy.RUNTIME)
public #interface Validate {
}
Example:
#Validate
public void testMe(BindingModel bindingModel, Errors errors) {
if (!errors.hasErrors()) {
// bindingModel is valid
}
}
And here's the modified aspect class:
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.core.MethodParameter;
import org.springframework.stereotype.Component;
import org.springframework.validation.Errors;
import org.springframework.validation.Validator;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
#Aspect
#Component
public class ValidateAspect {
private final Validator validator;
public ValidateAspect(Validator validator) {
this.validator = validator;
}
#Around("#annotation(Validate)")
public Object proceed(ProceedingJoinPoint pjp) throws Throwable {
MethodSignature methodSignature = (MethodSignature) pjp.getSignature();
List<MethodParameter> methodParameters = getMethodParameters(methodSignature);
for (int i = 0; i < methodParameters.size() - 1; i++) {
MethodParameter parameter = methodParameters.get(i);
MethodParameter nextParameter = methodParameters.get(i + 1);
if (!Errors.class.isAssignableFrom(nextParameter.getParameterType())) {
// the Errors argument has to be right after the validated argument to form a pair
continue;
}
Object target = pjp.getArgs()[methodParameters.indexOf(parameter)];
Errors errors = (Errors) pjp.getArgs()[methodParameters.indexOf(nextParameter)];
validator.validate(target, errors);
}
return pjp.proceed();
}
private static List<MethodParameter> getMethodParameters(MethodSignature methodSignature) {
return IntStream
.range(0, methodSignature.getParameterNames().length)
.mapToObj(i -> new MethodParameter(methodSignature.getMethod(), i))
.collect(Collectors.toList());
}
}
The above code is tested and (so far) seems to work properly with Spring Boot 2.1.4.RELEASE

Autowire dependency in builder class with static instantiation method

I'm pondering this builder class that should calculate a hash from the field values. Maybe this in itself is wrong for starters, but at the moment it seems to me that it belongs there because I'm striving to an immutable Article.
I would like to autowire/inject ArticleMD5HashCalculator but when I put #Autowired on the field, IntelliJ complains: field injection is not recommended. Constructor injection is not possible because it's a builder pattern class, which means it has a private constructor without parameters and a static method for instantiation where it would be awkward to pass in hashCalculator.
The builder is injected into a scraper. The scraper will reuse the same builder for many articles. When Spring creates the builder with prototype scope, the builder will carry old values when the next article doesn't overwrite the old values.
New'ing the hashCalculator results is a hard dependency, making it impractical to inject mocks. What is the best way to handle this situation?
Here's the code of how it is now:
import org.observer.media.utils.ArticleMD5HashCalculator;
import org.observer.media.utils.MD5HashCalculator;
import java.time.ZonedDateTime;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class ArticleBuilder {
private ArticleMD5HashCalculator hashCalculator;
private String headline;
private String subheading;
private String lead;
// other article fields...
private ArticleBuilder() {
// This seems wrong.
this.hashCalculator = new ArticleMD5HashCalculator(new MD5HashCalculator());
}
public static ArticleBuilder article() {
return new ArticleBuilder();
}
public ArticleBuilder withHeadline(String headline) {
this.headline = headline;
return this;
}
//Other with-methods...
public Article build() {
// calculateHash() is called in the 9th argument.
return new Article(headline, subheading, lead, body, images, quotations, subArticles, url, calculateHash(), author, sources, category, subjects, index, medium, company, datePublished, dateFetched);
}
private String calculateHash() {
return hashCalculator.hash(headline, subheading, lead, body, quotations, datePublished, dateFetched);
}
}

Assumptions:
There is one to one relationship between ArticleBuilder and ArticleMD5HashCalculator. Meaning you don't plan to inject different instances of hashCalculator into ArticleBuilder at different places in the project (essentially having multiple instances of ArticleBuilder)
You can change the ArticleBuilder impl as follows
public class ArticleBuilder {
private ArticleMD5HashCalculator hashCalculator;
public ArticleBuilder(ArticleMD5HashCalculator hashCalculator) {
this.hashCalculator = hashCalculator;
}
}
You can create a spring bean of type ArticleMD5HashCalculator and have this injected into a spring bean of type ArticleBuilder the following way.
#Configuration
public class ArticleConfig {
#Bean
public ArticleMD5HashCalculator articleMD5HashCalculator() {
return new ArticleMD5HashCalculator(new MD5HashCalculator());
}
#Bean
public ArticleBuilder() {
return new ArticleBuilder(articleMD5HashCalculator());
}
}
You can autowire ArticleBuilder elsewhere in your project and use it as a builder.
I am not sure why you made a private constructor and a static method to invoke that. I assume it is because you want a singleton ArticleBuilder. That can be achieved with the above approach. Correct me if I am wrong about this.
Update 1:
Based on the information you provided in the comments, you are injecting ArticleBuilder in a Scraper object and you want to have a way of getting a new instance of ArticleBuilder every time. You can use spring #Lookup annotation for that.
Stub implementation of Scraper class.
public class Scraper {
//assuming this is the method where you want to use ArticleBuilder
public void scrape() {
getArticleBuilder();
}
//You can even pass constructor arguments to this method.
//They will be used to match a constructor on the target bean and that gets invoked
#Lookup
public ArticleBuilder getArticleBuilder() {
//Spring creates a runtime implementation of this method.
return null;
}
}
You can call getArticleBuilder anytime you want a new instance of the bean. If it is declared prototype, you will always get a new instance of the bean.
But the only caveat with this is that Lookup annotation is not going to work with beans created with #Bean annotation. You alternate config may look like this.
#Component
#Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public class ArticleBuilder {
#Autowired
private ArticleMD5HashCalculator hashCalculator;
public ArticleBuilder(ArticleMD5HashCalculator hashCalculator) {
this.hashCalculator = hashCalculator;
}
}
#Component
public class ArticleMD5HashCalculator {
public ArticleMD5HashCalculator(MD5HashCalculator hashCalculator) {
this.hashCalculator = hashCalculator;
}
}
beans.xml:
<beans>
<bean class="MD5HashCalculator" />
<!-- Fully qualified class name is needed -->
</beans>

Also due to convention used in Spring documentation please use constructor-based injection when possible.
The Spring team generally advocates constructor injection as it enables one to implement application components as immutable objects and to ensure that required dependencies are not null.
Full info (scroll a little): Spring DOCS

I brewed up this alternative approach to pull out the new'ing and to open a window for injecting mocks. The solution implies that the builder has to be instantiated and recreated by a factory.
The factory:
import org.observer.media.hash.ArticleHashCalculator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.time.ZonedDateTime;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
#Component
public class ArticleBuilderFactory {
private ArticleHashCalculator articleHashCalculator;
#Autowired
public ArticleBuilderFactory(ArticleHashCalculator articleHashCalculator) {
this.articleHashCalculator = articleHashCalculator;
}
public ArticleBuilder create() {
return new ArticleBuilder(articleHashCalculator);
}
public class ArticleBuilder {
private ArticleHashCalculator articleHashCalculator;
private String headline;
private String subheading;
//...
private ArticleBuilder(ArticleHashCalculator articleHashCalculator) {
this.articleHashCalculator = articleHashCalculator;
}
public ArticleBuilderFactory.ArticleBuilder withIndex(int index) {
this.index = index;
return this;
}
public ArticleBuilderFactory.ArticleBuilder withHeadline(String headline) {
this.headline = headline;
return this;
}
//...
public Article build() {
return new Article(headline, subheading, lead, body, images, quotations, subArticles, url, calculateHash(), author, sources, category, subjects, index, medium, company, datePublished, dateFetched);
}
private String calculateHash() {
return articleHashCalculator.hash(headline, subheading, lead, body, quotations, datePublished, dateFetched);
}
}
}
Usage of the factory:
import org.junit.Test;
import org.junit.runner.RunWith;
import org.observer.media.hash.ArticleMD5HashCalculator;
import org.observer.media.hash.MD5HashCalculator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringRunner;
import static org.assertj.core.api.Java6Assertions.assertThat;
#RunWith(SpringRunner.class)
#ContextConfiguration(classes = {
ArticleBuilderFactory.class,
MD5HashCalculator.class,
ArticleMD5HashCalculator.class
})
public class ArticleBuilderFactoryTest {
private static final String HEADLINE = "headline";
private static final String LEAD = "lead";
private static final String BODY = "body";
#Autowired
private ArticleBuilderFactory articleBuilderFactory;
#Autowired
private ArticleMD5HashCalculator hashCalculator;
#Test
public void build() {
ArticleBuilderFactory.ArticleBuilder articleBuilder = articleBuilderFactory.create();
Article article = articleBuilder
.withHeadline(HEADLINE)
.withLead(LEAD)
.withBody(BODY)
.build();
assertThat(article.getHeadline()).isEqualTo(HEADLINE);
assertThat(article.getLead()).isEqualTo(LEAD);
assertThat(article.getBody()).isEqualTo(BODY);
assertThat(article.getHash()).isEqualTo(hashCalculator.hash(HEADLINE, null, LEAD, BODY, null, null, null));
}
}
ArticleMD5HashCalculator has #Component:
#Component
public class ArticleMD5HashCalculator {
}

Use #Validated and #Valid with spring validator

I have a java bean being used to send JSON messages to a spring #RestController and I have bean validation setup and running just fine using #Valid. But I want to move to Protobuf/Thrift and move away from REST. It is an internal API and a lot of big companies have done away with REST internally. What this really means is that I no longer have control of the message objects - they are generated externally. I can't put annotations on them anymore.
So now my validation has to be programmatic. How do I do this? I have coded up a Validator and it works just great. But it doesn't use the nice #Valid annotation. I have to do the following:
#Service
public StuffEndpoint implements StuffThriftDef.Iface {
#Autowired
private MyValidator myValidator;
public void things(MyMessage msg) throws BindException {
BindingResult errors = new BeanPropertyBindingResult(msg, msg.getClass().getName());
errors = myValidator.validate(msg);
if (errors.hasErrors()) {
throw new BindException(errors);
} else {
doRealWork();
}
}
}
This stinks. I have to do this in every single method. Now, I can put a lot of that into one method that throws BindException and that makes it one line of code to add to every method. But that's still not great.
What I want is to see it look like this:
#Service
#Validated
public StuffEndpoint implements StuffThriftDef.Iface {
public void things(#Valid MyMessage msg) {
doRealWork();
}
}
And still get the same result. Remember, my bean has no annotations. And yes, I know I can use the #InitBinder annotation on a method. But that only works for web requests.
I don't mind injecting the correct Validator into this class, but I would prefer if my ValidatorFactory could pull the correct one based on the supports() method.
Is this possible? Is there a way to configure bean validation to actually use Spring validation instead? Do I have to hijack a Aspect somewhere? Hack into the LocalValidatorFactory or the MethodValidationPostProcessor?
Thanks.

Its pretty complicated thing to combine Spring validation and JSR-303 constrains. And there is no 'ready to use' way. The main inconvenience is that Spring validation uses BindingResult, and JSR-303 uses ConstraintValidatorContext as result of validation.
You can try to make your own validation engine, using Spring AOP. Let's consider, what we need to do for it. First of all, declare AOP dependencies (if you didn't yet):
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>1.8.8</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>1.8.8</version>
</dependency>
I'm using Spring of version 4.2.4.RELEASE, but of cause you can use your own. AspectJ needed for use aspect annotation. Next step, we have to create simple validator registry:
public class CustomValidatorRegistry {
private List<Validator> validatorList = new ArrayList<>();
public void addValidator(Validator validator){
validatorList.add(validator);
}
public List<Validator> getValidatorsForObject(Object o) {
List<Validator> result = new ArrayList<>();
for(Validator validator : validatorList){
if(validator.supports(o.getClass())){
result.add(validator);
}
}
return result;
}
}
As you see it is very simple class, which allow us to find validator for object. Now lets create annotation, that will be mark methods, that need to be validated:
package com.mydomain.validation;
#Target({ElementType.METHOD})
#Retention(RetentionPolicy.RUNTIME)
public #interface CustomValidation {
}
Because of standard BindingException class is not RuntimeException, we can't use it in overriden methods. This means we need define our own exception:
public class CustomValidatorException extends RuntimeException {
private BindingResult bindingResult;
public CustomValidatorException(BindingResult bindingResult){
this.bindingResult = bindingResult;
}
public BindingResult getBindingResult() {
return bindingResult;
}
}
Now we are ready to create an aspect that will do most of the work. Aspect will execute before methods, which marked with CustomValidation annotation:
#Aspect
#Component
public class CustomValidatingAspect {
#Autowired
private CustomValidatorRegistry registry; //aspect will use our validator registry
#Before(value = "execution(public * *(..)) && annotation(com.mydomain.validation.CustomValidation)")
public void doBefore(JoinPoint point){
Annotation[][] paramAnnotations =
((MethodSignature)point.getSignature()).getMethod().getParameterAnnotations();
for(int i=0; i<paramAnnotations.length; i++){
for(Annotation annotation : paramAnnotations[i]){
//checking for standard org.springframework.validation.annotation.Validated
if(annotation.annotationType() == Validated.class){
Object arg = point.getArgs()[i];
if(arg==null) continue;
validate(arg);
}
}
}
}
private void validate(Object arg) {
List<Validator> validatorList = registry.getValidatorsForObject(arg);
for(Validator validator : validatorList){
BindingResult errors = new BeanPropertyBindingResult(arg, arg.getClass().getSimpleName());
validator.validate(arg, errors);
if(errors.hasErrors()){
throw new CustomValidatorException(errors);
}
}
}
}
execution(public * *(..)) && #annotation(com.springapp.mvc.validators.CustomValidation) means, that this aspect will applied to any public methods of beans, which marked with #CustomValidation annotation. Also note, that to mark validated parameters we are using standard org.springframework.validation.annotation.Validated annotation. But of cause we could make our custom. I think other code of aspect is very simple and does not need any comments. Further code of example validator:
public class PersonValidator implements Validator {
#Override
public boolean supports(Class<?> aClass) {
return aClass==Person.class;
}
#Override
public void validate(Object o, Errors errors) {
Person person = (Person)o;
if(person.getAge()<=0){
errors.rejectValue("age", "Age is too small");
}
}
}
Now we have make tune the configuration and all ready to use:
#Configuration
#ComponentScan(basePackages = "com.mydomain")
#EnableAspectJAutoProxy(proxyTargetClass = true)
public class AppConfig{
.....
#Bean
public CustomValidatorRegistry validatorRegistry(){
CustomValidatorRegistry registry = new CustomValidatorRegistry();
registry.addValidator(new PersonValidator());
return registry;
}
}
Note, proxyTargetClass is true because we will use cglib class proxy.
Example of target method in service class:
#Service
public class PersonService{
#CustomValidation
public void savePerson(#Validated Person person){
....
}
}
Because of #CustomValidation annotation aspect will be applied, and because of #Validated annotation person will be validated. And example of usage of service in controller(or any other class):
#Controller
public class PersonConroller{
#Autowired
private PersonService service;
public String savePerson(#ModelAttribute Person person, ModelMap model){
try{
service.savePerson(person);
}catch(CustomValidatorException e){
model.addAttribute("errors", e.getBindingResult());
return "viewname";
}
return "viewname";
}
}
Keep in mind, that if you will invoke #CustomValidation from methods of PersonService class, validation will not work. Because it will invoke methods of original class, but not proxy. This means, that you can invoke this methods only from outside of class (from other classes), if you want validation to be working (eg #Transactional works same way).
Sorry for long post. My answer is not about 'simple declarative way', and possible you will do not need it. But I was curious resolve this problem.

I marked #Ken's answer as correct because it is. But I have taken it a little further and wanted to post what I have made. I hope anybody coming to this page will find it interesting. I might try to get it in front of the Spring folks to see if it might be something included in future releases.
The idea is to have a new annotation to replace #Valid. So I called it #SpringValid. Using this annotation would kick off the system put together above. Here are all the pieces:
SpringValid.java
package org.springframework.validation.annotation;
import static java.lang.annotation.ElementType.CONSTRUCTOR;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
#Target({METHOD, FIELD, CONSTRUCTOR, PARAMETER})
#Retention(RUNTIME)
public #interface SpringValid {
}
SpringValidationAspect.java
package org.springframework.validation;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.util.List;
#Aspect
#Component
public class SpringValidationAspect {
private SpringValidatorRegistry springValidatorRegistry;
#Autowired
public SpringValidationAspect(final SpringValidatorRegistry springValidatorRegistry) {
this.springValidatorRegistry = springValidatorRegistry;
}
public SpringValidatorRegistry getSpringValidatorRegistry() {
return springValidatorRegistry;
}
#Before("#target(org.springframework.validation.annotation.Validated) "
+ "&& execution(public * *(#org.springframework.validation.annotation.SpringValid (*), ..)) "
+ "&& args(validationTarget)")
public void beforeMethodThatNeedsValidation(Object validationTarget) {
validate(validationTarget);
}
private void validate(Object arg) {
List<Validator> validatorList = springValidatorRegistry.getValidatorsForObject(arg);
for (Validator validator : validatorList) {
BindingResult errors = new BeanPropertyBindingResult(arg, arg.getClass().getSimpleName());
validator.validate(arg, errors);
if (errors.hasErrors()) {
throw new SpringValidationException(errors);
}
}
}
}
Spring's examples show classes annotated with #Validated so I wanted to keep that. The above aspect only targets classes with #Validated at the class-level. And, just like when you use #Valid, it looks for the #SpringValid annotation stuck to a method parameter.
SpringValidationException.java
package org.springframework.validation;
import org.springframework.validation.BindingResult;
public class SpringValidationException extends RuntimeException {
private static final long serialVersionUID = 1L;
private BindingResult bindingResult;
public SpringValidationException(final BindingResult bindingResult) {
this.bindingResult = bindingResult;
}
public BindingResult getBindingResult() {
return bindingResult;
}
}
SpringValidatorRegistry.java
package org.springframework.validation;
import org.springframework.validation.Validator;
import java.util.ArrayList;
import java.util.List;
public class SpringValidatorRegistry {
private List<Validator> validatorList = new ArrayList<>();
public void addValidator(Validator validator) {
validatorList.add(validator);
}
public List<Validator> getValidatorsForObject(Object o) {
List<Validator> result = new ArrayList<>();
for (Validator validator : validatorList) {
if (validator.supports(o.getClass())) {
result.add(validator);
}
}
return result;
}
}
Just like the first answer, a place to register all classes that implement Spring's org.springframework.validation.Validator interface.
SpringValidator.java
package org.springframework.validation.annotation;
import org.springframework.stereotype.Component;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
#Target(ElementType.TYPE)
#Retention(RetentionPolicy.RUNTIME)
#Documented
#Component
public #interface SpringValidator {
}
This is just extra sauce to make it easier to register/find Validators. You could register all your Validators by hand, or you could find them via reflection. So this part is not required, I just thought it made things easier.
MyConfig.java
package com.example.config;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.validation.SpringValidationAspect;
import org.springframework.validation.SpringValidatorRegistry;
import org.springframework.validation.annotation.SpringValidator;
import java.util.Map;
import javax.validation.Validator;
#Configuration
public class MyConfig {
#Autowired
private ApplicationContext applicationContext;
#Bean
public SpringValidatorRegistry validatorRegistry() {
SpringValidatorRegistry registry = new SpringValidatorRegistry();
Map<String, Object> validators =
applicationContext.getBeansWithAnnotation(SpringValidator.class);
validators.values()
.forEach(v -> registry.addValidator((org.springframework.validation.Validator) v));
return registry;
}
#Bean
public SpringValidationAspect springValidationAspect() {
return new SpringValidationAspect(validatorRegistry());
}
}
See, scan your classpath and look for #SpringValidator classes and register them. Then register the Aspect and away you go.
Here is an example of such a Validator:
MyMessageValidator.java
package com.example.validators;
import com.example.messages.MyMessage;
import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;
import org.springframework.validation.annotation.SpringValidator;
#SpringValidator
public class MyMessageValidator implements Validator {
#Override
public boolean supports(Class<?> clazz) {
return MyMessage.class.isAssignableFrom(clazz);
}
#Override
public void validate(Object target, Errors errors) {
ValidationUtils.rejectIfEmpty(errors, "firstField", "{javax.validation.constraints.NotNull}",
"firstField cannot be null");
MyMessage obj = (MyMessage) target;
if (obj.getSecondField != null && obj.getSecondField > 100) {
errors.rejectField(errors, "secondField", "{javax.validation.constraints.Max}", "secondField is too big");
}
}
}
And here is the service class that uses the #SpringValid annotation:
MyService.java
package com.example.services;
import com.example.messages.MyMessage;
import org.springframework.validation.annotation.SpringValid;
import org.springframework.validation.annotation.Validated;
import javax.inject.Inject;
#Validated
public class MyService {
public String doIt(#SpringValid final MyMessage msg) {
return "we did it!";
}
}
Hope this makes sense for someone at some point. I personally think it is quite useful. A lot of companies are starting to move their internal APIs away from REST and to something like Protobuf or Thrift. You can still use Bean Validation but you have to use XML, and it isn't all that nice. So I hope this will be helpful to people who want to still do programmatic validation.

Hope it helps someone. I've got it working by adding the following configuration:
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;
import org.springframework.validation.beanvalidation.MethodValidationPostProcessor;
#Configuration
public class ValidatorConfiguration {
#Bean
public MethodValidationPostProcessor getMethodValidationPostProcessor(){
MethodValidationPostProcessor processor = new MethodValidationPostProcessor();
processor.setValidator(this.validator());
return processor;
}
#Bean
public LocalValidatorFactoryBean validator(){
return new LocalValidatorFactoryBean();
}
}
The service is then annotated the same way (#Validated on the class and #Valid on the parameter) and can be injected into another bean where the method can be called directly and validation happens.

Spring constructor injection of SLF4J logger - how to get injection target class?

I'm trying to use Spring to inject a SLF4J logger into a class like so:
#Component
public class Example {
private final Logger logger;
#Autowired
public Example(final Logger logger) {
this.logger = logger;
}
}
I've found the FactoryBean class, which I've implemented. But the problem is that I cannot get any information about the injection target:
public class LoggingFactoryBean implements FactoryBean<Logger> {
#Override
public Class<?> getObjectType() {
return Logger.class;
}
#Override
public boolean isSingleton() {
return false;
}
#Override
public Logger getObject() throws Exception {
return LoggerFactory.getLogger(/* how do I get a hold of the target class (Example.class) here? */);
}
}
Is FactoryBean even the right way to go? When using picocontainers factory injection, you get the Type of the target passed in. In guice it is a bit trickier. But how do you accomplish this in Spring?

Here is an alternative to your solution. You could achieve your goal with BeanFactoryPostProcessor implementation.
Let's assume you want to have a class with logging. Here it is:
package log;
import org.apache.log4j.Logger;
#Loggable
public class MyBean {
private Logger logger;
}
As you could see this class does nothing and created just to be a logger container for simplicity. The only remarkable thing here is #Loggable annotation.
Here its source code:
package log;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.TYPE)
public #interface Loggable {
}
This annotation is only a marker for further processing. And here is a most interesting part:
package log;
import org.apache.log4j.Logger;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import java.lang.reflect.Field;
public class LoggerBeanFactoryPostProcessor implements BeanFactoryPostProcessor{
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
String[] names = beanFactory.getBeanDefinitionNames();
for(String name : names){
Object bean = beanFactory.getBean(name);
if(bean.getClass().isAnnotationPresent(Loggable.class)){
try {
Field field = bean.getClass().getDeclaredField("logger");
field.setAccessible(true);
field.set(bean, Logger.getLogger(bean.getClass()));
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}
It searches through all beans, and if a bean is marked as #Loggable, it initialize its private field with name logger. You could go even further and pass some parameters in #Loggable annotation. For example, it could be a name of field corresponding to logger.
I used Log4j in this example, but I guess it should work exactly the same way with slf4j.

To make your code more Spring aware use the InjectionPoint to define the loggers, i.e.:
#Bean
#Scope("prototype")
public Logger logger(InjectionPoint ip) {
return Logger.getLogger(ip.getMember().getDeclaringClass());
}
#Scope("prototype") is needed here to create 'logger' bean instance every time method is called.

I resolved it with a custom BeanFactory. If anyone comes up with a better solution, I would be happy to hear it. Anyway, here's the bean factory:
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.TypeConverter;
import org.springframework.beans.factory.config.DependencyDescriptor;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
public class CustomBeanFactory extends DefaultListableBeanFactory {
public CustomBeanFactory() {
}
public CustomBeanFactory(DefaultListableBeanFactory delegate) {
super(delegate);
}
#Override
public Object resolveDependency(DependencyDescriptor descriptor,
String beanName, Set<String> autowiredBeanNames,
TypeConverter typeConverter) throws BeansException {
//Assign Logger parameters if required
if (descriptor.isRequired()
&& Logger.class.isAssignableFrom(descriptor
.getMethodParameter().getParameterType())) {
return LoggerFactory.getLogger(descriptor.getMethodParameter()
.getDeclaringClass());
} else {
return super.resolveDependency(descriptor, beanName,
autowiredBeanNames, typeConverter);
}
}
}
Example usage with an XML config:
CustomBeanFactory customBeanFactory = new CustomBeanFactory();
GenericApplicationContext ctx = new GenericApplicationContext(customBeanFactory);
XmlBeanDefinitionReader xmlReader = new XmlBeanDefinitionReader(ctx);
xmlReader.loadBeanDefinitions(new ClassPathResource("beans.xml"));
ctx.refresh();
EDIT:
Below you can find Arend v. Reinersdorffs improved version (see the comments for an explanation).
import java.lang.reflect.Field;
import java.util.Set;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.TypeConverter;
import org.springframework.beans.factory.config.DependencyDescriptor;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.core.MethodParameter;
public class CustomBeanFactory extends DefaultListableBeanFactory {
public CustomBeanFactory() {
}
public CustomBeanFactory(DefaultListableBeanFactory delegate) {
super(delegate);
}
#Override
public Object resolveDependency(DependencyDescriptor descriptor,
String beanName, Set<String> autowiredBeanNames,
TypeConverter typeConverter) throws BeansException {
//Assign Logger parameters if required
if (Logger.class == descriptor.getDependencyType()) {
return LoggerFactory.getLogger(getDeclaringClass(descriptor));
} else {
return super.resolveDependency(descriptor, beanName,
autowiredBeanNames, typeConverter);
}
}
private Class<?> getDeclaringClass(DependencyDescriptor descriptor) {
MethodParameter methodParameter = descriptor.getMethodParameter();
if (methodParameter != null) {
return methodParameter.getDeclaringClass();
}
Field field = descriptor.getField();
if (field != null) {
return field.getDeclaringClass();
}
throw new AssertionError("Injection must be into a method parameter or field.");
}
}

Try something like:
#Component
public class Example {
#Autowired
#Qualifier("exampleLogger")
private final Logger logger;
}
And:
<bean id="exampleLogger" class="org.slf4j.LoggerFactory" factory-method="getLogger">
<constructor-arg type="java.lang.Class" value="package.Example"/>
</bean>

Since Spring 4.3.0 you can use InjectionPoint or DependencyDescriptor as parameters for bean producing methods:
#Component
public class LoggingFactoryBean {
#Bean
public Logger logger(InjectionPoint injectionPoint) {
Class<?> targetClass = injectionPoint.getMember().getDeclaringClass();
return LoggerFactory.getLogger(targetClass);
}
}

Yeah, you are going in the wrong direction. If I were you I would inject the LoggerFactory. If you want to hide that it is slf4j then I'd define a LoggerFactory interface and inject a class which delegates through to slf4j Logger.
public interface LoggerFactory {
public Logger getLogger(Class<?> clazz);
}
...
import org.slf4j.LoggerFactory;
public class Slf4jLoggerFactory implements LoggerFactory {
public Logger getLogger(Class<?> clazz) {
return org.slf4j.LoggerFactory.getLogger(clazz);
}
}
However, before you go there, this is approximately what org.apache.commons.logging is doing right? http://commons.apache.org/logging/
You use Log's instead of Loggers:
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class CLASS {
private Log log = LogFactory.getLog(CLASS.class);
...
Apache then looks through the classpath to see if you have log4j or others and delegates to the "best" one that it finds. Slf4j replaces log4j in the classpath so if you have it loaded (and apache log4j excluded) commons logging will delegate to it instead.

Why are you creating a new logger for each instance? The typical pattern is to have one logger per class (as a private static member).
If you really do want to do it that way: Maybe you can write a logger factory class, and inject that? Something like:
#Singleton
public class LogFactory {
public Logger getLogger(Object o) {
return LoggerFactory.getLogger(o.getClass());
}
}

I am trying to get this feature into official SLF4J API. Please support/vote/contribute: https://issues.jboss.org/browse/JBLOGGING-62
(this feature is already implemented by JBoss Logging + Seam Solder, see http://docs.jboss.org/seam/3/latest/reference/en-US/html/solder-logging.html)
11.4. Native logger API
You can also inject a "plain old" Logger (from the JBoss Logging API):
import javax.inject.Inject;
import org.jboss.logging.Logger;
public class LogService {
#Inject
private Logger log;
public void logMessage() {
log.info("Hey sysadmins!");
}
}
Log messages created from this Logger will have a category (logger name) equal to the fully-qualified class name of the bean implementation class. You can specify a category explicitly using an annotation.
#Inject #Category("billing")
private Logger log;
You can also specify a category using a reference to a type:
#Inject #TypedCategory(BillingService.class)
private Logger log;
Sorry for not providing a relevant answer.