data class ObjectA(
        @JSONField(serialize = false)
        var a:String?=""
){
    fun getB():String? = this.a
    fun setB(v:String){
        this.a = "b"
    }
}

fun testjson3(){
    var a:ObjectA = ObjectA()
    a.a = "c"
    val json:String = JSON.toJSONString(a)
    println(json)
    val obj:ObjectA = JSON.parseObject(json, ObjectA::class.java)
    println(obj)
}

{"b":"c"}
ObjectA(a=null)