[Kotlin] import com.google.gson.*

build.gradle (Module: app)

android {
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

dependencies {
    // com.google.gson
    implementation 'com.squareup.retrofit2:converter-gson:2.7.1'
}

 

 

 

 

 

 

Privacy.kt

package com.jwsoft.kotlinproject

data class Privacy (
    var height: Int,
    var weight: Int
)

 

 

 

 

 

 

 

User.kt

package com.jwsoft.kotlinproject

data class User (
    var name: String,
    var age: Int,
    var hobby: Array<String>,
    var privacy: Privacy
)

 

 

 

 

 

 

 

MainActivity.kt

package com.jwsoft.kotlinproject

import android.os.Bundle
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import com.google.gson.Gson

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // user 1
        val jsonString = "{" +
                " 'name':'James Kim'," +
                " 'age':30" +
                " }"

        val gson = Gson()
        var user: User = gson.fromJson(jsonString, User::class.java)
        Log.e("name", user.name)
        Log.e("age", user.age.toString())

        var jsonUser = gson.toJson(user)
        Log.e("jsonUser", jsonUser)


        // user 2
        var arrHobby = arrayOf("music", "movice")
        var privacy = Privacy(184, 84)
        var user2 = User("Sonata Lee", 27, arrHobby, privacy)

        var jsonUser2 = gson.toJson(user2)
        Log.e("jsonUser2", jsonUser2)

        var user3: User = gson.fromJson(jsonUser2, User::class.java)
        Log.e("name", user3.name)
        Log.e("age", user3.age.toString())

        for (i in 0 until user3.hobby.size) {
            Log.e("hobby $i", user3.hobby[i])
        }

        Log.e("privacy", user3.privacy.toString())
        Log.e("height", user3.privacy.height.toString())
        Log.e("weight", user3.privacy.weight.toString())
    }

}

실행 결과

 

 

 

 

 

 

 

---

MainActivity.kt

package com.jwsoft.kotlinproject

import android.os.Bundle
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import com.google.gson.Gson
import com.google.gson.GsonBuilder

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        var userMap: HashMap<String, Any> = HashMap()
        userMap["name"] = "James Kim"
        userMap["age"] = 30

        val arrHobby: Array<String> = arrayOf("music", "movie")
        userMap["hobby"] = arrHobby

        val privacy = Privacy(184, 84)
        userMap["privacy"] = privacy

        val gson = GsonBuilder().create()
        val jsonUser = gson.toJson(userMap)

        Log.e("jsonUser", jsonUser)

        var map = gson.fromJson(jsonUser, HashMap::class.java)
        Log.e("map", map.toString())

        var user = gson.fromJson(jsonUser, User::class.java)
        Log.e("name", user.name)
        Log.e("age", user.age.toString())
    }

}

실행 결과

 

 

 

 

 

 

 

---

MainActivity.kt

package com.jwsoft.kotlinproject

import android.os.Bundle
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import com.google.gson.Gson
import com.google.gson.GsonBuilder
import com.google.gson.JsonArray
import com.google.gson.JsonObject

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        var jsonObject: JsonObject = JsonObject()
        jsonObject.addProperty("name", "James Kim")
        jsonObject.addProperty("age", 30)

        var hobbyArray = JsonArray()
        hobbyArray.add("music")
        hobbyArray.add("movie")
        jsonObject.add("hobby", hobbyArray)

        var privacy = JsonObject()
        privacy.addProperty("height", 184)
        privacy.addProperty("weight", 84)
        jsonObject.add("privacy", privacy)

        Log.e("jsonObject", jsonObject.toString())

        val gson = GsonBuilder().setPrettyPrinting().create()
        val jsonString = gson.toJson(jsonObject)
        Log.e("jsonString", jsonString)

        val user = gson.fromJson(jsonObject, User::class.java)
        Log.e("name", user.name)
        Log.e("age", user.age.toString())

    }

}

val gson = Gson() 에서

val gson = GsonBuilder().setPrettyPrinting().create() 로 수정

콘솔 출력 시 예쁘게 출력됨.

 

실행 결과