CODEWITHSUNDEEP
kotlinfastjson
Forest Yang
Forest Yang

Reputation: 21

kotlin with fastjson parse object error: default constructor not found

I am trying use fastjson parse object in Kotlin code. but exception happened when I use JSON.parseObject, here are detail:

My data class:

    import com.alibaba.fastjson.JSONObject

    data class StatesMessage @JvmOverloads constructor(val command: String = 
        "states", var states: States = States()) {

      fun toJsonString(): String {
          return JSONObject.toJSONString(this)
      }

      data class States(var x: Double = 0.0, var y: Double = 0.0)
    }

Then I try to get object from string:

val state = JSON.parseObject(s, StatesMessage::class.java)

But exception throw from fastjson:

Caused by: com.alibaba.fastjson.JSONException: default constructor not found. 
    class com.example.demo.StatesMessage
   at com.alibaba.fastjson.util.JavaBeanInfo.build(JavaBeanInfo.java:475)
   at com.alibaba.fastjson.util.JavaBeanInfo.build(JavaBeanInfo.java:221)
   at com.alibaba.fastjson.parser.ParserConfig.createJavaBeanDeserializer(ParserConfig.java:670)
   at com.alibaba.fastjson.parser.ParserConfig.getDeserializer(ParserConfig.java:587)
   at com.alibaba.fastjson.parser.ParserConfig.getDeserializer(ParserConfig.java:398)
   at com.alibaba.fastjson.parser.DefaultJSONParser.parseObject(DefaultJSONParser.java:665)
   at com.alibaba.fastjson.JSON.parseObject(JSON.java:365)
   at com.alibaba.fastjson.JSON.parseObject(JSON.java:269)
   at com.alibaba.fastjson.JSON.parseObject(JSON.java:488)
   at com.example.demo.StartupRunner.run(StartupRunner.kt:25)
   at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:813)
... 5 more

all code refer to https://github.com/forest-yang/koltinjson

Upvotes: 1

Views: 1205

Answers (1)

Forest Yang
Forest Yang

Reputation: 21

I think it's a fastjson (till 1.2.54) bug. When I change to gson, it's work.

    /* it will throw exception
    val state = JSON.parseObject(s, StatesMessage::class.java)
    */
    val state = Gson().fromJson(s, StatesMessage::class.java)
    logger.info(state.states.x)
    logger.info(state.states.y)

Upvotes: 1

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