[kotlin] JacksonUtil (beautify JSON) - INDENT_OUTPUT

import com.fasterxml.jackson.core.type.TypeReference
import com.fasterxml.jackson.databind.DeserializationFeature
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.databind.SerializationFeature
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer
import com.fasterxml.jackson.module.afterburner.AfterburnerModule
import com.fasterxml.jackson.module.kotlin.KotlinModule
import java.time.LocalDate
import java.time.LocalDateTime
import java.time.format.DateTimeFormatter

object JacksonUtil {
    val objectMapper: ObjectMapper = ObjectMapper()
        .registerModule(KotlinModule.Builder().build())
        .registerModule(JavaTimeModule())
        .registerModule(AfterburnerModule())
        .configure(SerializationFeature.INDENT_OUTPUT, true)
        .configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false)
        .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
        .configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false)
        .registerModule(
            JavaTimeModule().apply {
                addDeserializer(LocalDate::class.java, LocalDateDeserializer(DateTimeFormatter.ISO_DATE))
                addDeserializer(
                    LocalDateTime::class.java,
                    LocalDateTimeDeserializer(DateTimeFormatter.ISO_DATE_TIME)
                )
            }
        )

    fun toJson(obj: Any?): String {
        if (obj == null) {
            return ""
        }

        return objectMapper.writeValueAsString(obj)
    }

    fun merged(a: MutableMap<String, Any>, b: Any): Map<String, Any> {
        return objectMapper
            .readerForUpdating(a)
            .readValue(toJson(b))
    }

    inline fun <reified T> toObject(s: String): T {
        return objectMapper.readValue(s, object : TypeReference<T>() {})
    }
}

https://stackoverflow.com/questions/5457524/json-beautifier-library-for-java

JSON Beautifier Library for Java