feat : BeanSerializerModifier 를 이용한 직렬화 설정 방법 예제 추가

놀이터(예제 코드 작성)/jackson/src/main/kotlin/com/banjjoknim/playground/jackson/jsonserialize/CarSerializers.kt

@@ -3,10 +3,15 @@ package com.banjjoknim.playground.jackson.jsonserialize
 import com.banjjoknim.playground.jackson.common.Car
 import com.banjjoknim.playground.jackson.common.Secret
 import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.databind.BeanDescription
+import com.fasterxml.jackson.databind.SerializationConfig
 import com.fasterxml.jackson.databind.SerializerProvider
 import com.fasterxml.jackson.databind.introspect.Annotated
 import com.fasterxml.jackson.databind.introspect.AnnotatedMember
 import com.fasterxml.jackson.databind.introspect.JacksonAnnotationIntrospector
+import com.fasterxml.jackson.databind.module.SimpleModule
+import com.fasterxml.jackson.databind.ser.BeanPropertyWriter
+import com.fasterxml.jackson.databind.ser.BeanSerializerModifier
 import com.fasterxml.jackson.databind.ser.std.StdSerializer
 
 /**
@@ -125,3 +130,29 @@ class SecretAnnotationSerializer(private val substituteValue: String) : StdSeria
         gen.writeString(substituteValue)
     }
 }
+
+/**
+ * 직렬화될 프로퍼티를 수정하도록 하는 방법이다.
+ *
+ * BeanSerializerModifier#changeProperties() 를 재정의한 뒤,
+ *
+ * SimpleModule 을 이용해서 ObjectMapper 에 등록한다.
+ *
+ * 아래처럼 하면 직렬화 대상에서 완전히 제외된다(`@JsonIgnore`와 동일한 효과).
+ *
+ * @see com.fasterxml.jackson.databind.ser.BeanSerializerModifier
+ * @see com.fasterxml.jackson.databind.module.SimpleModule
+ */
+class SecretBeanSerializerModifier : BeanSerializerModifier() {
+    override fun changeProperties(
+        config: SerializationConfig,
+        beanDesc: BeanDescription,
+        beanProperties: MutableList<BeanPropertyWriter>
+    ): MutableList<BeanPropertyWriter> {
+        SimpleModule()
+        return beanProperties
+            .filter { property -> property.getAnnotation(Secret::class.java) == null }
+            .toMutableList()
+//        return super.changeProperties(config, beanDesc, beanProperties)
+    }
+}

놀이터(예제 코드 작성)/jackson/src/test/kotlin/com/banjjoknim/playground/jackson/jsonserialize/CarSerializersTest.kt

@@ -148,7 +148,7 @@ class CarSerializersTest {
         }
 
         @Test
-        fun `@Secret 어노테이션을 적용하여 직렬화한다`() {
+        fun `@Secret 어노테이션, AnnotationIntrospector 을 적용하여 직렬화한다`() {
             // given
             mapper.setAnnotationIntrospector(SecretAnnotationIntrospector())
 
@@ -159,6 +159,24 @@ class CarSerializersTest {
             assertThat(actual).isEqualTo("""{"name":"banjjoknim","secret":"****","price":10000000,"owner":{"name":"ban","age":30}}""")
         }
 
+        @Test
+        fun `@Secret 어노테이션, BeanSerializerModifier 를 적용하여 직렬화한다`() {
+            // given
+            val module = object : SimpleModule() {
+                override fun setupModule(context: SetupContext) {
+                    super.setupModule(context)
+                    context.addBeanSerializerModifier(SecretBeanSerializerModifier())
+                }
+            }
+            mapper.registerModule(module)
+
+            // when
+            val actual = mapper.writeValueAsString(carUsingSecretAnnotation)
+
+            // then
+            assertThat(actual).isEqualTo("""{"name":"banjjoknim","price":10000000,"owner":{"name":"ban","age":30}}""")
+        }
+
         /**
          *
          * Kotlin + Spring Boot 를 사용한다면 `com.fasterxml.jackson.module:jackson-module-kotlin` 의존성을 사용할 것이다.