feat: 프론트엔드와의 PK 호환을 위한 Long <-> String ObjectMapper 모듈 추가

src/main/kotlin/roomescape/common/config/JacksonConfig.kt

@@ -1,6 +1,9 @@
 package roomescape.common.config
 
-import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.core.JsonParser
+import com.fasterxml.jackson.databind.*
+import com.fasterxml.jackson.databind.module.SimpleModule
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule
 import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer
 import com.fasterxml.jackson.datatype.jsr310.deser.LocalTimeDeserializer
@@ -9,6 +12,8 @@ import com.fasterxml.jackson.datatype.jsr310.ser.LocalTimeSerializer
 import com.fasterxml.jackson.module.kotlin.kotlinModule
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
+import roomescape.common.exception.CommonErrorCode
+import roomescape.common.exception.RoomescapeException
 import java.time.LocalDate
 import java.time.LocalTime
 import java.time.format.DateTimeFormatter
@@ -20,6 +25,7 @@ class JacksonConfig {
     fun objectMapper(): ObjectMapper = ObjectMapper()
         .registerModule(javaTimeModule())
         .registerModule(kotlinModule())
+        .registerModule(longIdModule())
 
     private fun javaTimeModule(): JavaTimeModule = JavaTimeModule()
         .addSerializer(
@@ -38,4 +44,35 @@ class JacksonConfig {
             LocalTime::class.java,
             LocalTimeDeserializer(DateTimeFormatter.ofPattern("HH:mm"))
         ) as JavaTimeModule
+
+    private fun longIdModule(): SimpleModule {
+        val simpleModule = SimpleModule()
+        simpleModule.addSerializer(Long::class.java, LongToStringSerializer())
+        simpleModule.addDeserializer(Long::class.java, StringToLongDeserializer())
+        return simpleModule
+    }
+}
+
+class LongToStringSerializer : JsonSerializer<Long>() {
+    override fun serialize(value: Long?, gen: JsonGenerator, serializers: SerializerProvider) {
+        if (value == null) {
+            gen.writeNull()
+        } else {
+            gen.writeString(value.toString())
+        }
+    }
+}
+
+class StringToLongDeserializer : JsonDeserializer<Long>() {
+    override fun deserialize(p: JsonParser, ctxt: DeserializationContext): Long? {
+        val text = p.text
+        if (text.isNullOrBlank()) {
+            return null
+        }
+        return try {
+            text.toLong()
+        } catch (_: NumberFormatException) {
+            throw RoomescapeException(CommonErrorCode.INVALID_INPUT_VALUE)
+        }
+    }
 }

src/test/kotlin/roomescape/common/config/JacksonConfigTest.kt

@@ -52,4 +52,18 @@ class JacksonConfigTest(
             }.message shouldContain "Text '$hour:$minute:$sec' could not be parsed"
         }
     }
+
+    context("Long 타입은 문자열로 (역)직렬화된다.") {
+        val number = 1234567890L
+        val serialized: String = objectMapper.writeValueAsString(number)
+        val deserialized: Long = objectMapper.readValue(serialized, Long::class.java)
+
+        test("Long 직렬화") {
+            serialized shouldBe "$number"
+        }
+
+        test("Long 역직렬화") {
+            deserialized shouldBe number
+        }
+    }
 })