Configure JSON-B to serialize snake_case globally.

customer-api-provider/src/main/java/de/schulung/sample/quarkus/boundary/CustomerDto.java

@@ -1,6 +1,5 @@
 package de.schulung.sample.quarkus.boundary;
 
-import jakarta.json.bind.annotation.JsonbProperty;
 import jakarta.json.bind.annotation.JsonbTransient;
 import jakarta.validation.constraints.NotNull;
 import jakarta.validation.constraints.Pattern;
@@ -25,8 +24,8 @@ public class CustomerDto {
   @Size(min = 3, max = 100)
   @NotNull
   private String name;
-  @JsonbProperty("birth_date") // TODO -> use snake_case globally?
-  private LocalDate birthdate;
+  //@JsonbProperty("birth_date")
+  private LocalDate birthDate;
   @Pattern(regexp = "active|locked|disabled")
   @NotNull
   private String state;

customer-api-provider/src/main/java/de/schulung/sample/quarkus/boundary/CustomerDtoMapper.java

@@ -1,13 +1,17 @@
 package de.schulung.sample.quarkus.boundary;
 
 import de.schulung.sample.quarkus.domain.Customer;
+import org.mapstruct.InheritInverseConfiguration;
 import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
 
 @Mapper(componentModel = "cdi")
 public interface CustomerDtoMapper {
 
+  @Mapping(source = "birthDate", target = "birthdate")
   Customer map(CustomerDto source);
 
+  @InheritInverseConfiguration
   CustomerDto map(Customer source);
 
   default String mapState(Customer.CustomerState source) {

customer-api-provider/src/main/java/de/schulung/sample/quarkus/boundary/config/JsonSnakeCaseConfiguration.java

@@ -0,0 +1,18 @@
+package de.schulung.sample.quarkus.boundary.config;
+
+import io.quarkus.jsonb.JsonbConfigCustomizer;
+import jakarta.enterprise.context.Dependent;
+import jakarta.json.bind.JsonbConfig;
+import jakarta.json.bind.config.PropertyNamingStrategy;
+
+@Dependent
+public class JsonSnakeCaseConfiguration implements JsonbConfigCustomizer {
+
+  @Override
+  public void customize(JsonbConfig jsonbConfig) {
+    jsonbConfig.withPropertyNamingStrategy(
+      PropertyNamingStrategy.LOWER_CASE_WITH_UNDERSCORES
+    );
+  }
+
+}