Develop Reference

The problem of extracting the error message of Class-level constraints

I have created a custom validation annotation to check if the password and confirm password are equal. All the things work fine, but the only issue is I cannot get the field name anymore since it is a class-level constraint instead of field. I only can use the getAllErrors() to get the default message. (Refer to this image)
AddUserDTO
#Data
#NoArgsConstructor
#AllArgsConstructor
#ConfirmPassword
public class AddUsersEntityDTO {
//...blablabla
#NotBlank(message ="Password is required")
#Size(min = 6, message = "Password must be more than 5 characters")
public String password;
#NotBlank(message ="Confirm Password is required")
public String confirmPassword;
}
Validator
#Target({ElementType.TYPE})
#Retention(RetentionPolicy.RUNTIME)
#Constraint(validatedBy = ConfirmPasswordValidation.class)
public #interface ConfirmPassword {
String message() default "Confirm password is not same with the password";
Class<?>[] groups() default { };
Class<? extends Payload>[] payload() default { };
}
public class ConfirmPasswordValidation implements ConstraintValidator<ConfirmPassword, AddUsersEntityDTO> {
#Override
public void initialize(ConfirmPassword constraintAnnotation) {
}
#Override
public boolean isValid(AddUsersEntityDTO addUsersEntityDTO, ConstraintValidatorContext constraintValidatorContext) {
return addUsersEntityDTO.getConfirmPassword().equals(addUsersEntityDTO.getPassword());
}
}

Csutom annotation to validate Dto contains two list using java validation and spring boot

I have a class Wrapper that contains two arraylist and another properties :
public class Wrapper<T, E> {
private List<T> toInsert = new ArrayList<>();
private List<T> toUpdate = new ArrayList<>();
private Set<E> toDelete = new HashSet<>();
// getter setter ....
}
I have a Class Dto :
public class UserDto {
private long id;
private LocalDateTime createdDate;
#NotBlank
private String registrationNumber;
#NotBlank
private String firstName;
#NotBlank
private String lastName;
#NotBlank
private String email;
#NotBlank
}
I create a validator :
#Target({ElementType.FIELD, ElementType.PARAMETER})
#Retention(RetentionPolicy.RUNTIME)
#Constraint(validatedBy = {CustomerLocationValidator.class})
#Documented
public #interface ValidCustomerLocation {
String message() default "Invalid List userDto";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
The implementation of validator annotation :
public class CustomerLocationValidator implements ConstraintValidator<ValidCustomerLocation, Wrapper<UserDto, String>> {
#Autowired
Validator validator;
#Override
public boolean isValid(Wrapper<UserDto, String> value, ConstraintValidatorContext constraintValidatorContext) {
boolean isValid = true;
final Set<ConstraintViolation<UserDto>> constraintViolations = new HashSet();
value.getToInsert().forEach(userDto -> constraintViolations.addAll( validator.validate(userDto)) );
if (!CollectionUtils.isEmpty(constraintViolations)) {
constraintValidatorContext.disableDefaultConstraintViolation();
for (ConstraintViolation<UserDto> violation : constraintViolations) {
constraintValidatorContext.buildConstraintViolationWithTemplate(violation.getMessageTemplate()).addConstraintViolation();
}
isValid = false;
}
return isValid;
}
}
The method in controller :
#PostMapping
public ResponseEntity<Void> save(
#RequestBody #ValidCustomerLocation Wrapper<UserDto, String> itemsUsers) {}
In this controlller I try to send invalid data but the annotation ValidCustomerLocation didn't catch the error , I try to use #Valid but i have the same problem

Spring Boot validation - one from two not null

I'm trying to validate if one of two fields are not null in Spring Boot?
I have set that in the method class for the main object:
#NotNull(message = "Username field is required")
private String username;
#NotNull(message = "Email field is required")
private String email;
but that will require to have both fields not null. Then I went with custom validation described here https://lmonkiewicz.com/programming/get-noticed-2017/spring-boot-rest-request-validation/ but I wasn't able to get that example to work. I have to stuck on
User class declaration:
#CombinedNotNull(fields = {"username","email"})
public class User implements {
private long id = 0L;
#NotNull(message = "First name field is required")
private String firstName;
#NotNull(message = "Last name field is required")
private String lastName;
private String username;
private String email;
#NotNull(message = "Status field is required")
private String status;
...all methods here...
...setters and getters...
}
CombibnedNotNull class:
#Documented
#Retention(RUNTIME)
#Target({ TYPE, ANNOTATION_TYPE })
#Constraint(validatedBy = userValidator.class)
public #interface CombinedNotNull {
String message() default "username or email is required";
Class<?>[] groups() default { };
Class<? extends Payload>[] payload() default { };
}
userValidator class:
#Component
public class userValidator implements ConstraintValidator<CombinedNotNull, User> {
#Override
public void initialize(final CombinedNotNull combinedNotNull) {
fields = combinedNotNull.fields();
}
#Override
public boolean isValid(final User user, final ConstraintValidatorContext context) {
final BeanWrapperImpl beanWrapper = new BeanWrapperImpl(user);
for (final String f : fields) {
final Object fieldValue = beanWrapper.getPropertyValue(f);
if (fieldValue == null) {
return false;
}
}
return true;
}
}
Is there any other way to get this done or should I go with the "complex" example from that page?

I'm assuming username OR email must not be null. Not XOR.
Add this getter in User class:
#AssertTrue(message = "username or email is required")
private boolean isUsernameOrEmailExists() {
return username != null || email != null;
}
In my experience, the method name must follow the getter name convention otherwise this won't work. For examples, getFoo or isBar.
This has a small problem: the field name from this validation error would be usernameOrEmailExists, only 1 error field. If that is not a concern, this might help.
But If you want to have username and email fields when errors occur, you can use this workaround:
public String getUsername() {
return username;
}
public String getEmail() {
return email;
}
#AssertTrue(message = "username or email is required")
private boolean isUsername() {
return isUsernameOrEmailExists();
}
#AssertTrue(message = "username or email is required")
private boolean isEmail() {
return isUsernameOrEmailExists();
}
private boolean isUsernameOrEmailExists() {
return username != null || email != null;
}
get... methods are just simple getters for general use, and is... are for validation. This will emit 2 validation errors with username and email fields.

I'll try to implement it for you (even if I'm without an IDE).
Inside ConstraintValidator#initialize you can get a hold of the configured fields' names which cannot be null.
#Override
public void initialize(final CombinedNotNull combinedNotNull) {
fields = combinedNotNull.fields();
}
Inside ConstraintValidator#isValid you can use those fields' names to check the Object fields.
#Override
public boolean isValid(final Object value, final ConstraintValidatorContext context) {
final BeanWrapperImpl beanWrapper = new BeanWrapperImpl(value);
for (final String f : fields) {
final Object fieldValue = beanWrapper.getPropertyValue(f);
if (fieldValue == null) {
return false;
}
}
return true;
}
Annotation:
import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
#Retention(RUNTIME)
#Target({ElementType.TYPE, ElementType.ANNOTATION_TYPE})
#Constraint(validatedBy = CombinedNotNullValidator.class)
public #interface CombinedNotNull {
String message() default "username or email is required";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
/**
* Fields to validate against null.
*/
String[] fields() default {};
}
The annotation could be applied as
#CombinedNotNull(fields = {
"fieldName1",
"fieldName2"
})
public class MyClassToValidate { ... }
To learn how to create a Class-level constraint annotation, refer always to the official documentation. Docs

If you want to validate that exactly one is set and the others are null:
Annotation
import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
#Retention(RUNTIME)
#Target({ElementType.TYPE, ElementType.ANNOTATION_TYPE})
#Constraint(validatedBy = OneNotNullValidator.class)
public #interface OneNotNull {
String message() default "Exactly one of the fields must be set and the other must be null";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
/**
* Fields to validate against null.
*/
String[] fields() default {};
}
Validator
import java.util.Arrays;
import java.util.Objects;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import org.springframework.beans.BeanWrapperImpl;
import org.springframework.stereotype.Component;
#Component
public class OneNotNullValidator implements ConstraintValidator<OneNotNull, Object> {
private String[] fields;
#Override
public void initialize(final OneNotNull combinedNotNull) {
fields = combinedNotNull.fields();
}
#Override
public boolean isValid(final Object obj, final ConstraintValidatorContext context) {
final BeanWrapperImpl beanWrapper = new BeanWrapperImpl(obj);
return Arrays.stream(fields)
.map(beanWrapper::getPropertyValue)
.filter(Objects::isNull)
.count()
== 1;
}
}
Usage
#OneNotNull(
fields = {"username","email"},
message="Either username or email must be set"
)
public class User {
private String username;
private String email;
// ...
}

How to configure direct field access on #Valid in Spring?

How can I tell spring-web to validate my dto without having to use getter/setter?
#PostMapping(path = "/test")
public void test(#Valid #RequestBody WebDTO dto) {
}
public class WebDTO {
#Valid //triggers nested validation
private List<Person> persons;
//getter+setter for person
#JsonAutoDetect(fieldVisibility = JsonAutoDetect.Visibility.ANY)
public static class Person {
#NotBlank
public String name;
public int age;
}
}
Result:
"java.lang.IllegalStateException","message":"JSR-303 validated property
'persons[0].name' does not have a corresponding accessor for Spring data
binding - check your DataBinder's configuration (bean property versus direct field access)"}
Special requirement: I still want to add #AssertTrue on boolean getters to provide crossfield validation, like:
#AssertTrue
#XmlTransient
#JsonIgnore
public boolean isNameValid() {
//...
}

you have to configure Spring DataBinder to use direct field access.
#ControllerAdvice
public class ControllerAdviceConfiguration {
#InitBinder
private void initDirectFieldAccess(DataBinder dataBinder) {
dataBinder.initDirectFieldAccess();
}
}

Try something like this:
#Access(AccessType.FIELD)
public String name;

spring combine two validation annotations in one

I'm using Spring+Hibernate+Spring-MVC.
I want to define a custom constraint combining two other predefined validation annotations: #NotNull #Size like this:
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
#NotNull
#Size(min=4)
public #interface JPasswordConstraint {
} // this is not correct. It's just a suggestion.
and I want to use this annotation in my form models.
public class ChangePasswordForm {
#NotNull
private String currentPass;
#JPasswordConstraint
private String newPass;
#JPasswordConstraint
private String newPassConfirm;
}
UserController.java
#RequestMapping(value = "/pass", method = RequestMethod.POST)
public String pass2(Model model, #Valid #ModelAttribute("changePasswordForm") ChangePasswordForm form, BindingResult result) {
model.addAttribute("changePasswordForm", form);
try {
userService.changePassword(form);
} catch (Exception ex) {
result.rejectValue(null, "error.objec", ex.getMessage());
System.out.println(result);
}
if (!result.hasErrors()) {
model.addAttribute("successMessage", "password changed successfully!");
}
return "user/pass";
}
But it does not work. It accepts the less than 4 character passwords.
How can I solve this problem?

This is a bit late, but technique of combining validation annotations described in
https://docs.jboss.org/hibernate/stable/validator/reference/en-US/html_single/?v=5.4#section-constraint-composition
Maybe it was not available, at the time of writing, but solution is following
#NotNull
#Size(min=4)
#Target({ METHOD, FIELD, ANNOTATION_TYPE })
#Retention(RUNTIME)
#Constraint(validatedBy = { })
#Documented
public #interface JPasswordConstraint {
String message() default "Password is invalid";
Class<?>[] groups() default { };
Class<? extends Payload>[] payload() default { };
}

You can add
#ConstraintComposition
Who is by default at AND
and if one day you want #NotNull or #Size
You add
#ConstraintComposition(OR)
Edit : this is an exemple who combine #Pattern(regexp = "[a-z]") and
#Size(min = 2, max = 3)
#ConstraintComposition(OR)
#Pattern(regexp = "[a-z]")
#Size(min = 2, max = 3)
#ReportAsSingleViolation
#Target({ METHOD, FIELD })
#Retention(RUNTIME)
#Constraint(validatedBy = { })
public #interface PatternOrSize {
String message() default "";
Class<?>[] groups() default { };
Class<? extends Payload>[] payload() default { };
}