Is there any way that we can use two custom error messages using spring-boot custom validation? - spring-boot

Question

I'm using the below custom validation code to validate personName and it seems to be working fine, but the problem is when am passing an EMPTY string, it is giving same error message instead of the empty error message. Can someone please help me with this?
#Documented
#Constraint(validatedBy = {PersonNameValidator.class})
#Target({METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE})
#Retention(RUNTIME)
#ReportAsSingleViolation
public #interface PersonName {
/**
* Default error message defined for the validator.
*
* #return message
*/
String message() default "invalid person name";
/**
* Method to define groups parameters for validation.
*
* #return groups
*/
Class[] groups() default {};
/**
* Method to load payload.
*
* #return payload
*/
Class<? extends Payload>[] payload() default {};
}
public class PersonNameValidator implements ConstraintValidator<PersonName, String> {
#Override
public boolean isValid(String name, ConstraintValidatorContext context) {
if (name.length() == 0) {
throw new IllegalArgumentException("must not be Empty");
} else if (!name.matches("(?=^(?!\\s*$).+)(^[^±!#£$%^&*_+§€#¢§¶•«\\\\/<>?:;|=]{1,256}$)")) {
throw new IllegalArgumentException("name should start with uppercase.");
}
return true;
}
}
#Data
public class NameDto {
#NotNull
#PersonName
private String family1Name;
#PersonName
private String family2Name;
#NotNull
#PersonName
private String givenName;
#PersonName
private String middleName;
}
Getting NullPointerException

Answer 1

#Name
#NotEmpty(message = "name cannot be empty")
String name;
should work
but if you want to join constraint you should use a custom ConstraintValidator add provide this validator via #Constraint(validatedBy = {YourCustomValidator.class}
see example below
full example
used dependency spring-boot-starter-validation (not needed if you use spring-boot-starter-web)
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
application.properties
upper.name=dirk
application
package stackoverflow.demo;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import javax.validation.Constraint;
import javax.validation.Payload;
import javax.validation.ReportAsSingleViolation;
import javax.validation.constraints.NotEmpty;
import javax.validation.constraints.Pattern;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;
import org.springframework.validation.annotation.Validated;
#SpringBootApplication
public class SoCustomValidationApplication {
public static void main(String[] args) {
SpringApplication.run(SoCustomValidationApplication.class, args);
}
}
#Component
class ConfigurationLoader{
final MyCustomValidatedProperties config;
ConfigurationLoader(MyCustomValidatedProperties config){
this.config = config;
}
#EventListener()
void showName() {
System.err.println("name is: " + config.getName());
}
}
#org.springframework.context.annotation.Configuration
#Validated
#ConfigurationProperties(prefix = "upper")
class MyCustomValidatedProperties {
#Uppercase
#NotEmpty(message = "name cannot be empty")
String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
#Constraint(validatedBy = {ValidNameValidator.class})
#Target({ElementType.FIELD})
#Retention(RetentionPolicy.RUNTIME)
#ReportAsSingleViolation
#interface Uppercase {
String message() default "name should start with uppercase";
Class[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
class ValidNameValidator implements ConstraintValidator<Uppercase, String> {
#Override
public boolean isValid(String name, ConstraintValidatorContext context) {
if (null == name || 0 == name.length() ) {
throw new IllegalArgumentException("name cannot be empty.");
} else if(!name.matches("^([A-Z][a-z]+)")) {
throw new IllegalArgumentException("name should start with uppercase.");
}
return true;
}
}
APPLICATION FAILED TO START
Description:
Binding to target org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under 'upper' to stackoverflow.demo.MyCustomValidatedProperties$$EnhancerBySpringCGLIB$$d0094cdb failed:
Property: upper.name
Value: dirk
Origin: class path resource [application.properties]:1:12
Reason: name should start with uppercase
and if you leave upper.name empty
upper.name=
APPLICATION FAILED TO START
Description:
Binding to target org.springframework.boot.context.properties.bind.BindException: Failed to bind properties under 'upper' to stackoverflow.demo.MyCustomValidatedProperties$$EnhancerBySpringCGLIB$$29925f50 failed:
Property: upper.name
Value:
Origin: class path resource [application.properties]:1:12
Reason: name cannot be empty
Property: upper.name
Value:
Origin: class path resource [application.properties]:1:12
Reason: name should start with uppercase