MoshiKotlin - 如何将 NULL JSON 字符串序列化为空字符串

如何将 NULL JSON 字符串序列化为空字符串？

kotlin
dependencies {
    implementation("com.squareup.moshi:moshi:1.12.0")
}

kotlin
import com.squareup.moshi.JsonAdapter
import com.squareup.moshi.JsonReader
import com.squareup.moshi.JsonWriter
import java.io.IOException
class NullToEmptyStringAdapter : JsonAdapter() {
    @Throws(IOException::class)
    override fun fromJson(reader: JsonReader): String? {
        if (reader.peek() == JsonReader.Token.NULL) {
            reader.nextNull()
            return ""
        }
        return reader.nextString()
    }
    @Throws(IOException::class)
    override fun toJson(writer: JsonWriter, value: String?) {
        if (value == null) {
            writer.nullValue()
        } else {
            writer.value(value)
        }
    }
}

kotlin
import com.squareup.moshi.Moshi
val moshi: Moshi = Moshi.Builder()
    .add(NullToEmptyStringAdapter())
    .build()

kotlin
data class User(
    val name: String?,
    val age: Int?
)
fun main() {
    val json = """{"name": null, "age": 25}"""
    val adapter = moshi.adapter(User::class.java)
    val user = adapter.fromJson(json)
    println("Name: ${user?.name}")
    println("Age: ${user?.age}")
    val serializedJson = adapter.toJson(user)
    println("Serialized JSON: $serializedJson")
}