Exposed Json Extension (works for MySQL)

exposed_ext.kt

import org.jetbrains.exposed.sql.Column
import org.jetbrains.exposed.sql.ColumnType
import org.jetbrains.exposed.sql.Table


fun <T : Any> Table.json(name: String, klass: Class<T>): Column<T> =
    registerColumn(name, JsonTyped(klass))

class JsonTyped<T : Any>(private val klass: Class<T>) : ColumnType() {
    private val mapper = defaultObjectMapper // Please change this to whatever
    override fun sqlType(): String = "json"

    override fun valueFromDB(value: Any): Any {
        try {
            return mapper.readValue(value.toString(), klass)
        } catch (e: Exception) {
            // Logger here
            throw RuntimeException("Can't parse JSON: '$value' to '$klass'")
        }
    }

    override fun notNullValueToDB(value: Any): Any = mapper.writeValueAsString(value)
    override fun nonNullValueToString(value: Any): String = "'${mapper.writeValueAsString(value)}'"
}