Encapsulation of conversion between Json and objects (Gson)

I. Preface

Some time ago, due to the backend of spring boot, it was often necessary to convert between Json and objects, so using Gson combined with the characteristics of Kotlin extension functions to encapsulate two very convenient functions, if it is in other languages, it can also be encapsulatedFor a moment, it is not convenient without Kotlin.The following shows the final packaging effect

Object to Json

val cat = Cat()cat.toMyJson()

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Json to Object

 //Single object, here it needs to be converted into a single object manually, mainlyis an example of a unified formval cat = Cat()val data = cat.toMyJson()data.toMyObject()[0]//list typeval cats = List()val dataList = cats.toMyObject()[0]

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2. Object to Json

This needs to be extended under Any. Since Any is the parent class of all classes, this is somewhat similar to Object in Java

fun Any.toMyJson():String{return Gson().toJson(this)}

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It can be used directly after encapsulation. Gson is not so difficult to deal with, but only the way of writing points saves the time of bracketing

val cat = Cat()cat.toMyJson()

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Three, Json transfer object

This is a bit problematic when encapsulating it at first. First of all, it is easier to find the extended object, which is the String type, but there is one thing that needs to be paid attention to. Here, the reflection mechanism is used for Gson conversion, so two processes need to be done

• Generic materialization processing
• Dealing with reflection-related issues

Final code effect

inline fun  String.toMyObject(): List {val listType: Type = `$Gson$Types`.newParameterizedTypeWithOwner(null, ArrayList::class.java, T::class.java)return if(!contains("[")){Gson().fromJson("[${this}]", listType)}else{Gson().fromJson(this, listType)}}

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Use of packaging

val cat = Cat()val data = cat.toMyJson()data.toMyObject()[0]

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However, there is a disadvantage here that if it is a single object, you need to manually take the first value as the object, because the return value is of the list type. If there is a way to change the return value type, please leave a message in the comment area

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Fourth, issues that need attention

Object to Json needs attention

This only needs to pay attention to the format after conversion, list or single object can be directly converted

Json to object needs attention

What needs to be noted is that the type of the object should be clear, and the non-Json format string cannot be converted successfully, although it has this method, and then my current plan is to convert it into a unified list type, so you need to manually get the value

V. Summary

It was quite a headache when I encountered these before, and I often needed to go back and forth. Many articles on the Internet did not explain it clearly. Although the packaged library is only a few lines of code, in short, convenient development is the bestYes, the simpler the better.