BAEL-7119: Localized Validation Messages in REST (#14996)

* BAEL-7119: Localized Validation Messages in REST

* BAEL-7119: Localized Validation Messages in REST
- Remove unused imports

spring-boot-modules/spring-boot-mvc/pom.xml

@@ -91,6 +91,10 @@
             <artifactId>aspectjweaver</artifactId>
             <version>${aspectjweaver.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+        </dependency>
     </dependencies>
 
     <build>

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/RestValidationApplication.java

@@ -0,0 +1,15 @@
+package com.baeldung.restvalidation;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.ComponentScan;
+
+@SpringBootApplication
+@ComponentScan(basePackages = { "com.baeldung.restvalidation" })
+public class RestValidationApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(RestValidationApplication.class, args);
+    }
+
+}

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/config/MessageConfig.java

@@ -0,0 +1,38 @@
+package com.baeldung.restvalidation.config;
+
+import javax.validation.MessageInterpolator;
+
+import org.hibernate.validator.messageinterpolation.ResourceBundleMessageInterpolator;
+import org.springframework.context.MessageSource;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.support.ReloadableResourceBundleMessageSource;
+import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;
+import org.springframework.validation.beanvalidation.MessageSourceResourceBundleLocator;
+
+@Configuration
+public class MessageConfig {
+
+    @Bean
+    public MessageSource messageSource() {
+        ReloadableResourceBundleMessageSource messageSource = new ReloadableResourceBundleMessageSource();
+        messageSource.setBasename("classpath:CustomValidationMessages");
+        messageSource.setDefaultEncoding("UTF-8");
+        return messageSource;
+    }
+
+    @Bean
+    public MessageInterpolator getMessageInterpolator(MessageSource messageSource) {
+        MessageSourceResourceBundleLocator resourceBundleLocator = new MessageSourceResourceBundleLocator(messageSource);
+        ResourceBundleMessageInterpolator messageInterpolator = new ResourceBundleMessageInterpolator(resourceBundleLocator);
+        return new RecursiveLocaleContextMessageInterpolator(messageInterpolator);
+    }
+
+    @Bean
+    public LocalValidatorFactoryBean getValidator(MessageInterpolator messageInterpolator) {
+        LocalValidatorFactoryBean bean = new LocalValidatorFactoryBean();
+        bean.setMessageInterpolator(messageInterpolator);
+        return bean;
+    }
+
+}

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/config/RecursiveLocaleContextMessageInterpolator.java

@@ -0,0 +1,36 @@
+package com.baeldung.restvalidation.config;
+
+import java.util.Locale;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import javax.validation.MessageInterpolator;
+
+import org.hibernate.validator.messageinterpolation.AbstractMessageInterpolator;
+import org.hibernate.validator.messageinterpolation.ResourceBundleMessageInterpolator;
+
+public class RecursiveLocaleContextMessageInterpolator extends AbstractMessageInterpolator {
+
+    private static final Pattern PATTERN_PLACEHOLDER = Pattern.compile("\\{([^}]+)\\}");
+
+    private final MessageInterpolator interpolator;
+
+    public RecursiveLocaleContextMessageInterpolator(ResourceBundleMessageInterpolator interpolator) {
+        this.interpolator = interpolator;
+    }
+
+    @Override
+    public String interpolate(MessageInterpolator.Context context, Locale locale, String message) {
+        int level = 0;
+        while (containsPlaceholder(message) && (level++ < 2)) {
+            message = this.interpolator.interpolate(message, context, locale);
+        }
+        return message;
+    }
+
+    private boolean containsPlaceholder(String code) {
+        Matcher matcher = PATTERN_PLACEHOLDER.matcher(code);
+        return matcher.find();
+    }
+
+}

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/response/InputFieldError.java

@@ -0,0 +1,12 @@
+package com.baeldung.restvalidation.response;
+
+import lombok.*;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class InputFieldError {
+    private String field;
+    private String message;
+
+}

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/response/UpdateUserResponse.java

@@ -0,0 +1,17 @@
+package com.baeldung.restvalidation.response;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+
+import java.util.List;
+
+import lombok.*;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+@JsonInclude(JsonInclude.Include.NON_NULL)
+public class UpdateUserResponse {
+
+    private List<InputFieldError> fieldErrors;
+
+}

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/service1/User.java

@@ -0,0 +1,15 @@
+package com.baeldung.restvalidation.service1;
+
+import javax.validation.constraints.NotEmpty;
+
+import lombok.*;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class User {
+
+    @NotEmpty
+    private String email;
+
+}

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/service1/UserService1.java

@@ -0,0 +1,36 @@
+package com.baeldung.restvalidation.service1;
+
+import org.springframework.http.*;
+import org.springframework.validation.BindingResult;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+import javax.validation.Valid;
+
+import com.baeldung.restvalidation.response.InputFieldError;
+import com.baeldung.restvalidation.response.UpdateUserResponse;
+
+@RestController
+public class UserService1 {
+
+    @PutMapping(value = "/user1", produces = MediaType.APPLICATION_JSON_VALUE)
+    public ResponseEntity<UpdateUserResponse> updateUser(@RequestBody @Valid User user,
+                                                         BindingResult bindingResult) {
+        if (bindingResult.hasFieldErrors()) {
+
+            List<InputFieldError> fieldErrorList = bindingResult.getFieldErrors().stream()
+                .map(error -> new InputFieldError(error.getField(), error.getDefaultMessage()))
+                .collect(Collectors.toList());
+
+            UpdateUserResponse updateResponse = new UpdateUserResponse(fieldErrorList);
+            return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(updateResponse);
+        }
+        else {
+            // Update logic...
+            return ResponseEntity.status(HttpStatus.OK).build();
+        }
+    }
+
+}

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/service2/User.java

@@ -0,0 +1,15 @@
+package com.baeldung.restvalidation.service2;
+
+import javax.validation.constraints.NotEmpty;
+
+import lombok.*;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class User {
+
+    @NotEmpty(message = "{validation.email.notEmpty}")
+    private String email;
+
+}

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/service2/UserService2.java

@@ -0,0 +1,40 @@
+package com.baeldung.restvalidation.service2;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+import javax.validation.Valid;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.BindingResult;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.baeldung.restvalidation.response.InputFieldError;
+import com.baeldung.restvalidation.response.UpdateUserResponse;
+
+@RestController
+public class UserService2 {
+
+    @PutMapping(value = "/user2", produces = MediaType.APPLICATION_JSON_VALUE)
+    public ResponseEntity<UpdateUserResponse> updateUser(@RequestBody @Valid User user,
+                                                         BindingResult bindingResult) {
+        if (bindingResult.hasFieldErrors()) {
+
+            List<InputFieldError> fieldErrorList = bindingResult.getFieldErrors().stream()
+                .map(error -> new InputFieldError(error.getField(), error.getDefaultMessage()))
+                .collect(Collectors.toList());
+
+            UpdateUserResponse updateResponse = new UpdateUserResponse(fieldErrorList);
+            return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(updateResponse);
+        }
+        else {
+            // Update logic...
+            return ResponseEntity.status(HttpStatus.OK).build();
+        }
+    }
+
+}

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/service3/FieldNotEmpty.java

@@ -0,0 +1,32 @@
+package com.baeldung.restvalidation.service3;
+
+import static java.lang.annotation.ElementType.ANNOTATION_TYPE;
+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.ElementType.TYPE_USE;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import javax.validation.Constraint;
+import javax.validation.Payload;
+
+@Documented
+@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE })
+@Retention(RUNTIME)
+@Constraint(validatedBy = { FieldNotEmptyValidator.class })
+public @interface FieldNotEmpty {
+
+    String message() default "{validation.notEmpty}";
+
+    String field() default "Field";
+
+    Class<?>[] groups() default {};
+
+    Class<? extends Payload>[] payload() default {};
+
+}

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/service3/FieldNotEmptyValidator.java

@@ -0,0 +1,16 @@
+package com.baeldung.restvalidation.service3;
+
+import javax.validation.ConstraintValidator;
+import javax.validation.ConstraintValidatorContext;
+
+public class FieldNotEmptyValidator implements ConstraintValidator<FieldNotEmpty, Object> {
+
+    private String message;
+    private String field;
+
+    @Override
+    public boolean isValid(Object value, ConstraintValidatorContext context) {
+        return (value != null && !value.toString().trim().isEmpty());
+    }
+
+}

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/service3/User.java

@@ -0,0 +1,13 @@
+package com.baeldung.restvalidation.service3;
+
+import lombok.*;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class User {
+
+    @FieldNotEmpty(message = "{validation.notEmpty}", field = "{field.personalEmail}")
+    private String email;
+
+}

spring-boot-modules/spring-boot-mvc/src/main/java/com/baeldung/restvalidation/service3/UserService3.java

@@ -0,0 +1,40 @@
+package com.baeldung.restvalidation.service3;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+import javax.validation.Valid;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.BindingResult;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.baeldung.restvalidation.response.InputFieldError;
+import com.baeldung.restvalidation.response.UpdateUserResponse;
+
+@RestController
+public class UserService3 {
+
+    @PutMapping(value = "/user3", produces = MediaType.APPLICATION_JSON_VALUE)
+    public ResponseEntity<UpdateUserResponse> updateUser(@RequestBody @Valid User user,
+                                                         BindingResult bindingResult) {
+        if (bindingResult.hasFieldErrors()) {
+
+            List<InputFieldError> fieldErrorList = bindingResult.getFieldErrors().stream()
+                .map(error -> new InputFieldError(error.getField(), error.getDefaultMessage()))
+                .collect(Collectors.toList());
+
+            UpdateUserResponse updateResponse = new UpdateUserResponse(fieldErrorList);
+            return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(updateResponse);
+        }
+        else {
+            // Update logic...
+            return ResponseEntity.status(HttpStatus.OK).build();
+        }
+    }
+
+}

spring-boot-modules/spring-boot-mvc/src/main/resources/CustomValidationMessages.properties

@@ -0,0 +1,3 @@
+field.personalEmail=Personal Email
+validation.notEmpty={field} cannot be empty
+validation.email.notEmpty=Email cannot be empty

spring-boot-modules/spring-boot-mvc/src/main/resources/CustomValidationMessages_zh.properties

@@ -0,0 +1,3 @@
+field.personalEmail=個人電郵
+validation.notEmpty={field}不能是空白
+validation.email.notEmpty=電郵不能留空

spring-boot-modules/spring-boot-mvc/src/main/resources/ValidationMessages.properties

@@ -0,0 +1 @@
+javax.validation.constraints.NotEmpty.message=The field cannot be empty

spring-boot-modules/spring-boot-mvc/src/main/resources/ValidationMessages_zh.properties

@@ -0,0 +1 @@
+javax.validation.constraints.NotEmpty.message=本欄不能留空

spring-boot-modules/spring-boot-mvc/src/test/java/com/baeldung/restvalidation/service1/UserService1IntegrationTest.java

@@ -0,0 +1,75 @@
+package com.baeldung.restvalidation.service1;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Objects;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.http.*;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import com.baeldung.restvalidation.RestValidationApplication;
+import com.baeldung.restvalidation.response.InputFieldError;
+import com.baeldung.restvalidation.response.UpdateUserResponse;
+
+@ExtendWith(SpringExtension.class)
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, classes = RestValidationApplication.class)
+class UserService1IntegrationTest {
+
+    @Autowired
+    private TestRestTemplate restTemplate;
+
+    @Test
+    void whenUpdateValidEmail_thenReturnsOK() {
+
+        // When
+        ResponseEntity<UpdateUserResponse> responseEntity = updateUser(new User("test@email.com"), null);
+
+        // Then
+        assertEquals(HttpStatus.OK, responseEntity.getStatusCode());
+    }
+
+    @Test
+    void whenUpdateEmptyEmail_thenReturnsErrorMessageInEnglish() {
+
+        // When
+        ResponseEntity<UpdateUserResponse> responseEntity = updateUser(new User(""), null);
+
+        // Then
+        InputFieldError error = responseEntity.getBody().getFieldErrors().get(0);
+        assertEquals(HttpStatus.BAD_REQUEST, responseEntity.getStatusCode());
+        assertEquals("The field cannot be empty", error.getMessage());
+    }
+
+    @Test
+    void whenUpdateEmptyEmailWithLanguageHeaderEqualsToZh_thenReturnsErrorMessageInChinese() {
+
+        // When
+        ResponseEntity<UpdateUserResponse> responseEntity = updateUser(new User(""), "zh-tw");
+
+        // Then
+        InputFieldError error = responseEntity.getBody().getFieldErrors().get(0);
+        assertEquals(HttpStatus.BAD_REQUEST, responseEntity.getStatusCode());
+        assertEquals("本欄不能留空", error.getMessage());
+    }
+
+    private ResponseEntity<UpdateUserResponse> updateUser(User user, String language) {
+
+        HttpHeaders headers = new HttpHeaders();
+        if (Objects.nonNull(language)) {
+            headers.set(HttpHeaders.ACCEPT_LANGUAGE, language);
+        }
+
+        return restTemplate.exchange(
+            "/user1",
+            HttpMethod.PUT,
+            new HttpEntity<>(user, headers),
+            UpdateUserResponse.class
+        );
+    }
+
+}

spring-boot-modules/spring-boot-mvc/src/test/java/com/baeldung/restvalidation/service2/UserService2IntegrationTest.java

@@ -0,0 +1,75 @@
+package com.baeldung.restvalidation.service2;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Objects;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.http.*;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import com.baeldung.restvalidation.RestValidationApplication;
+import com.baeldung.restvalidation.response.InputFieldError;
+import com.baeldung.restvalidation.response.UpdateUserResponse;
+
+@ExtendWith(SpringExtension.class)
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, classes = RestValidationApplication.class)
+class UserService2IntegrationTest {
+
+    @Autowired
+    private TestRestTemplate restTemplate;
+
+    @Test
+    void whenUpdateValidEmail_thenReturnsOK() {
+
+        // When
+        ResponseEntity<UpdateUserResponse> responseEntity = updateUser(new User("test@email.com"), null);
+
+        // Then
+        assertEquals(HttpStatus.OK, responseEntity.getStatusCode());
+    }
+
+    @Test
+    void whenUpdateEmptyEmail_thenReturnsErrorMessageInEnglish() {
+
+        // When
+        ResponseEntity<UpdateUserResponse> responseEntity = updateUser(new User(""), null);
+
+        // Then
+        InputFieldError error = responseEntity.getBody().getFieldErrors().get(0);
+        assertEquals(HttpStatus.BAD_REQUEST, responseEntity.getStatusCode());
+        assertEquals("Email cannot be empty", error.getMessage());
+    }
+
+    @Test
+    void whenUpdateEmptyEmailWithLanguageHeaderEqualsToZh_thenReturnsErrorMessageInChinese() {
+
+        // When
+        ResponseEntity<UpdateUserResponse> responseEntity = updateUser(new User(""), "zh-tw");
+
+        // Then
+        InputFieldError error = responseEntity.getBody().getFieldErrors().get(0);
+        assertEquals(HttpStatus.BAD_REQUEST, responseEntity.getStatusCode());
+        assertEquals("電郵不能留空", error.getMessage());
+    }
+
+    private ResponseEntity<UpdateUserResponse> updateUser(User user, String language) {
+
+        HttpHeaders headers = new HttpHeaders();
+        if (Objects.nonNull(language)) {
+            headers.set(HttpHeaders.ACCEPT_LANGUAGE, language);
+        }
+
+        return restTemplate.exchange(
+            "/user2",
+            HttpMethod.PUT,
+            new HttpEntity<>(user, headers),
+            UpdateUserResponse.class
+        );
+    }
+
+}

spring-boot-modules/spring-boot-mvc/src/test/java/com/baeldung/restvalidation/service3/UserService3IntegrationTest.java

@@ -0,0 +1,75 @@
+package com.baeldung.restvalidation.service3;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Objects;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.http.*;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import com.baeldung.restvalidation.RestValidationApplication;
+import com.baeldung.restvalidation.response.InputFieldError;
+import com.baeldung.restvalidation.response.UpdateUserResponse;
+
+@ExtendWith(SpringExtension.class)
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, classes = RestValidationApplication.class)
+class UserService3IntegrationTest {
+
+    @Autowired
+    private TestRestTemplate restTemplate;
+
+    @Test
+    void whenUpdateValidEmail_thenReturnsOK() {
+
+        // When
+        ResponseEntity<UpdateUserResponse> responseEntity = updateUser(new User("test@email.com"), null);
+
+        // Then
+        assertEquals(HttpStatus.OK, responseEntity.getStatusCode());
+    }
+
+    @Test
+    void whenUpdateEmptyEmail_thenReturnsErrorMessageInEnglish() {
+
+        // When
+        ResponseEntity<UpdateUserResponse> responseEntity = updateUser(new User(""), null);
+
+        // Then
+        InputFieldError error = responseEntity.getBody().getFieldErrors().get(0);
+        assertEquals(HttpStatus.BAD_REQUEST, responseEntity.getStatusCode());
+        assertEquals("Personal Email cannot be empty", error.getMessage());
+    }
+
+    @Test
+    void whenUpdateEmptyEmailWithLanguageHeaderEqualsToZh_thenReturnsErrorMessageInChinese() {
+
+        // When
+        ResponseEntity<UpdateUserResponse> responseEntity = updateUser(new User(""), "zh-tw");
+
+        // Then
+        InputFieldError error = responseEntity.getBody().getFieldErrors().get(0);
+        assertEquals(HttpStatus.BAD_REQUEST, responseEntity.getStatusCode());
+        assertEquals("個人電郵不能是空白", error.getMessage());
+    }
+
+    private ResponseEntity<UpdateUserResponse> updateUser(User user, String language) {
+
+        HttpHeaders headers = new HttpHeaders();
+        if (Objects.nonNull(language)) {
+            headers.set(HttpHeaders.ACCEPT_LANGUAGE, language);
+        }
+
+        return restTemplate.exchange(
+            "/user3",
+            HttpMethod.PUT,
+            new HttpEntity<>(user, headers),
+            UpdateUserResponse.class
+        );
+    }
+
+}