diff --git a/src/main/java/icu/samnyan/aqua/api/model/resp/sega/maimai2/external/Maimai2DataExport.java b/src/main/java/icu/samnyan/aqua/api/model/resp/sega/maimai2/external/Maimai2DataExport.java
deleted file mode 100644
index b0e499e8..00000000
--- a/src/main/java/icu/samnyan/aqua/api/model/resp/sega/maimai2/external/Maimai2DataExport.java
+++ /dev/null
@@ -1,35 +0,0 @@
-package icu.samnyan.aqua.api.model.resp.sega.maimai2.external;
-
-import icu.samnyan.aqua.sega.maimai2.model.userdata.*;
-import lombok.AllArgsConstructor;
-import lombok.Data;
-import lombok.NoArgsConstructor;
-
-import java.util.List;
-
-/**
- * @author samnyan (privateamusement@protonmail.com)
- */
-@Data
-@AllArgsConstructor
-@NoArgsConstructor
-public class Maimai2DataExport {
-    public String gameId = "SDEZ";
-    public Mai2UserDetail userData;
-    public Mai2UserExtend userExtend;
-    public Mai2UserOption userOption;
-    public List<Mai2MapEncountNpc> mapEncountNpcList;
-    public List<Mai2UserAct> userActList;
-    public List<Mai2UserCharacter> userCharacterList;
-    public List<Mai2UserCharge> userChargeList;
-    public List<Mai2UserCourse> userCourseList;
-    public List<Mai2UserFavorite> userFavoriteList;
-    public List<Mai2UserFriendSeasonRanking> userFriendSeasonRankingList;
-    public List<Mai2UserGeneralData> userGeneralDataList;
-    public List<Mai2UserItem> userItemList;
-    public List<Mai2UserLoginBonus> userLoginBonusList;
-    public List<Mai2UserMap> userMapList;
-    public List<Mai2UserMusicDetail> userMusicDetailList;
-    public List<Mai2UserPlaylog> userPlaylogList;
-    public Mai2UserUdemae userUdemae;
-}
diff --git a/src/main/java/icu/samnyan/aqua/api/model/resp/sega/maimai2/external/Maimai2DataExport.kt b/src/main/java/icu/samnyan/aqua/api/model/resp/sega/maimai2/external/Maimai2DataExport.kt
new file mode 100644
index 00000000..6bd4356e
--- /dev/null
+++ b/src/main/java/icu/samnyan/aqua/api/model/resp/sega/maimai2/external/Maimai2DataExport.kt
@@ -0,0 +1,29 @@
+package icu.samnyan.aqua.api.model.resp.sega.maimai2.external
+
+import icu.samnyan.aqua.sega.maimai2.model.userdata.*
+
+data class Maimai2DataExport(
+    var userData: Mai2UserDetail,
+    var userExtend: Mai2UserExtend,
+    var userOption: Mai2UserOption,
+    var userUdemae: Mai2UserUdemae,
+    var mapEncountNpcList: List<Mai2MapEncountNpc>,
+    var userActList: List<Mai2UserAct>,
+    var userCharacterList: List<Mai2UserCharacter>,
+    var userChargeList: List<Mai2UserCharge>,
+    var userCourseList: List<Mai2UserCourse>,
+    var userFavoriteList: List<Mai2UserFavorite>,
+    var userFriendSeasonRankingList: List<Mai2UserFriendSeasonRanking>,
+    var userGeneralDataList: List<Mai2UserGeneralData>,
+    var userItemList: List<Mai2UserItem>,
+    var userLoginBonusList: List<Mai2UserLoginBonus>,
+    var userMapList: List<Mai2UserMap>,
+    var userMusicDetailList: List<Mai2UserMusicDetail>,
+    var userPlaylogList: List<Mai2UserPlaylog>,
+    var gameId: String = "SDEZ",
+) {
+    constructor() : this(Mai2UserDetail(), Mai2UserExtend(), Mai2UserOption(), Mai2UserUdemae(),
+        mutableListOf(), mutableListOf(), mutableListOf(), mutableListOf(), mutableListOf(), mutableListOf(),
+        mutableListOf(), mutableListOf(), mutableListOf(), mutableListOf(), mutableListOf(), mutableListOf(),
+        mutableListOf())
+}
diff --git a/src/main/java/icu/samnyan/aqua/net/games/ImportController.kt b/src/main/java/icu/samnyan/aqua/net/games/ImportController.kt
index c9df4e5a..22173eb6 100644
--- a/src/main/java/icu/samnyan/aqua/net/games/ImportController.kt
+++ b/src/main/java/icu/samnyan/aqua/net/games/ImportController.kt
@@ -1,6 +1,11 @@
 package icu.samnyan.aqua.net.games
 
+import com.fasterxml.jackson.core.JsonParser
+import com.fasterxml.jackson.databind.DeserializationContext
+import com.fasterxml.jackson.databind.JsonDeserializer
+import com.fasterxml.jackson.databind.module.SimpleModule
 import ext.JACKSON
+import ext.minus
 import ext.splitLines
 import java.lang.reflect.Field
 import kotlin.reflect.KClass
@@ -54,7 +59,7 @@ abstract class ImportController<T: Any>(
             lists[tb.name]?.add(obj) ?: field.set(data, obj)
         }
 
-        return ImportResult(errors, warnings, JACKSON.writeValueAsString(data))
+        return ImportResult(errors, warnings, JACKSON_ARTEMIS.writeValueAsString(data))
     }
 
     companion object
@@ -69,7 +74,7 @@ abstract class ImportController<T: Any>(
             // Process Nones
             dict = dict.filterValues { it != "None" }
 
-            return JACKSON.convertValue(dict, type.java)
+            return JACKSON_ARTEMIS.convertValue(dict, type.java)
         }
     }
 }
@@ -96,3 +101,18 @@ fun String.asSqlInsert(): SqlInsert {
     assert(cols.size == vals.size) { "Column and value count mismatch" }
     return SqlInsert(table, cols.zip(vals).toMap())
 }
+
+@Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+val JSON_INT_LIST_STR = SimpleModule().addDeserializer(List::class.java, object : JsonDeserializer<List<Integer>>() {
+    override fun deserialize(parser: JsonParser, context: DeserializationContext) =
+        try {
+            val text = parser.text.trim('[', ']')
+            if (text.isEmpty()) emptyList()
+            else text.split(',').map { it.trim().toInt() } as List<Integer>
+        } catch (e: Exception) {
+            400 - "Invalid list value ${parser.text}: $e" }
+})
+
+val JACKSON_ARTEMIS = JACKSON.copy().apply {
+    registerModule(JSON_INT_LIST_STR)
+}
diff --git a/src/main/java/icu/samnyan/aqua/net/games/Models.kt b/src/main/java/icu/samnyan/aqua/net/games/Models.kt
index 9e2edcfa..65bc3459 100644
--- a/src/main/java/icu/samnyan/aqua/net/games/Models.kt
+++ b/src/main/java/icu/samnyan/aqua/net/games/Models.kt
@@ -1,6 +1,7 @@
 package icu.samnyan.aqua.net.games
 
 import com.fasterxml.jackson.annotation.JsonIgnore
+import ext.JACKSON
 import ext.JavaSerializable
 import icu.samnyan.aqua.sega.general.model.Card
 import jakarta.persistence.*
@@ -11,6 +12,8 @@ import org.springframework.data.jpa.repository.JpaRepository
 import org.springframework.data.jpa.repository.Query
 import org.springframework.data.repository.NoRepositoryBean
 import java.util.*
+import kotlin.reflect.full.memberProperties
+import kotlin.reflect.jvm.isAccessible
 
 data class TrendOut(val date: String, val rating: Int, val plays: Int)
 
@@ -99,13 +102,16 @@ interface IGenericGamePlaylog {
     val isAllPerfect: Boolean
 }
 
+@Serializable
 @MappedSuperclass
 open class BaseEntity(
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     @JsonIgnore
     var id: Long = 0
-) : JavaSerializable
+) : JavaSerializable {
+    override fun toString() = JACKSON.writeValueAsString(this)
+}
 
 @NoRepositoryBean
 interface GenericUserDataRepo<T : IGenericUserData> : JpaRepository<T, Long> {
diff --git a/src/main/java/icu/samnyan/aqua/net/games/mai2/Mai2Import.kt b/src/main/java/icu/samnyan/aqua/net/games/mai2/Mai2Import.kt
index 529de2ad..3f9c235f 100644
--- a/src/main/java/icu/samnyan/aqua/net/games/mai2/Mai2Import.kt
+++ b/src/main/java/icu/samnyan/aqua/net/games/mai2/Mai2Import.kt
@@ -34,8 +34,5 @@ class Mai2Import : ImportController<Maimai2DataExport>(
         // "mai2_profile_region" to ImportClass(UserRegion::class),
     )
 ) {
-    override fun createEmpty() = Maimai2DataExport("SDEZ", Mai2UserDetail(), Mai2UserExtend(), Mai2UserOption(),
-        ArrayList(), ArrayList(), ArrayList(), ArrayList(), ArrayList(), ArrayList(),
-        ArrayList(), ArrayList(), ArrayList(), ArrayList(), ArrayList(), ArrayList(),
-        ArrayList(), Mai2UserUdemae())
+    override fun createEmpty() = Maimai2DataExport()
 }
\ No newline at end of file
diff --git a/src/main/java/icu/samnyan/aqua/net/games/mai2/Maimai2.kt b/src/main/java/icu/samnyan/aqua/net/games/mai2/Maimai2.kt
index 741d22f1..8106b4a8 100644
--- a/src/main/java/icu/samnyan/aqua/net/games/mai2/Maimai2.kt
+++ b/src/main/java/icu/samnyan/aqua/net/games/mai2/Maimai2.kt
@@ -12,11 +12,11 @@ import icu.samnyan.aqua.sega.maimai2.model.userdata.Mai2UserEntity
 import org.springframework.transaction.PlatformTransactionManager
 import org.springframework.transaction.support.TransactionTemplate
 import org.springframework.web.bind.annotation.RestController
-import java.lang.reflect.Field
 import java.time.LocalDateTime
 import java.util.*
 import kotlin.io.path.Path
 import kotlin.io.path.writeText
+import kotlin.reflect.KMutableProperty1
 import kotlin.reflect.full.declaredMembers
 
 @RestController
@@ -58,7 +58,7 @@ class Maimai2(
     }
 
     // Use reflection to get all properties in Mai2Repos with matching names in Maimai2DataExport
-    val exportFields: Map<Field, UserLinked<*>> = listOf(*Maimai2DataExport::class.java.declaredFields)
+    val exportFields: Map<KMutableProperty1<Maimai2DataExport, Any>, UserLinked<*>> = Maimai2DataExport::class.vars()
         .filter { f -> f.name !in setOf("gameId", "userData") }
         .associateWith { Mai2Repos::class.declaredMembers
             .filter { f -> f returns UserLinked::class }
@@ -66,15 +66,15 @@ class Maimai2(
             ?.call(repos) as UserLinked<*>? ?: error("No matching field found for ${it.name}")
         }
 
-    val listFields = exportFields.filter { it.key.type == List::class.java }
-    val singleFields = exportFields.filter { it.key.type != List::class.java }
+    val listFields = exportFields.filter { it.key returns List::class }
+    val singleFields = exportFields.filter { !(it.key returns List::class) }
 
     fun export(u: AquaNetUser) = Maimai2DataExport().apply {
         gameId = "SDEZ"
         userData = repos.userData.findByCard(u.ghostCard) ?: (404 - "User not found")
         exportFields.forEach { (f, u) ->
-            f.set(this, if (f.type == List::class.java) u.findByUser(userData)
-            else u.findSingleByUser(userData).orElse(null))
+            if (f returns List::class) f.set(this, u.findByUser(userData))
+            else u.findSingleByUser(userData)()?.let { f.set(this, it) }
         }
     }
 
@@ -84,13 +84,11 @@ class Maimai2(
     @Suppress("UNCHECKED_CAST")
     @API("import")
     fun importUserData(@RP token: Str, @RB json: Str) = us.jwt.auth(token) { u ->
-        val export = json.parseJson<Maimai2DataExport>()
+        val export = json.parseJackson<Maimai2DataExport>()
         if (!export.gameId.equals("SDEZ", true)) 400 - "Invalid game ID"
 
-        val lists = listFields.toList().associate { (f, r) -> r to f.gets<List<Mai2UserEntity>>(export) }.vNotNull()
-        val singles = singleFields.toList().associate { (f, r) -> r to f.gets<Mai2UserEntity>(export) }.vNotNull()
-
-        if (export.userData == null) 400 - "Invalid user data"
+        val lists = listFields.toList().associate { (f, r) -> r to f.get(export) as List<Mai2UserEntity> }.vNotNull()
+        val singles = singleFields.toList().associate { (f, r) -> r to f.get(export) as Mai2UserEntity }.vNotNull()
 
         // Validate new user data
         // Check that all ids are 0 (this should be true since all ids are @JsonIgnore)
@@ -120,8 +118,8 @@ class Maimai2(
             lists.values.flatten().forEach { it.user = nu }
             singles.values.forEach { it.user = nu }
             // Save new data
-            lists.forEach { (repo, list) -> (repo as UserLinked<Any>).saveAll(list) }
             singles.forEach { (repo, single) -> (repo as UserLinked<Any>).save(single) }
+            lists.forEach { (repo, list) -> (repo as UserLinked<Any>).saveAll(list) }
         }
 
         SUCCESS