预期 BEGIN_ARRAY 但在第 1 行第 2 列是 BEGIN_OBJECT。如何解决？

Posted 2023-04-18

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【中文标题】预期 BEGIN_ARRAY 但在第 1 行第 2 列是 BEGIN_OBJECT。如何解决？【英文标题】：Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2. How to solve it? 【发布时间】：2022-01-07 07:16:58 【问题描述】：

我正在尝试检索数据并将它们显示在回收站视图中。我正在进行改造，提出获取请求.. 一切都很好，除了：它不会在回收器中显示数据，因为它说： “应为 BEGIN_ARRAY，但在第 1 行第 2 列是 BEGIN_OBJECT”。我还使用 JSON 插件中的 kotlin 数据类文件从响应中生成数据类。我不知道该怎么办，我被卡住了..

这是我的课程：

ApiClient.kt

object ApiClient 

private const val BASE_URL: String = "https://dev.fastbeach.it/api/"

private val gson : Gson by lazy 
    GsonBuilder().setLenient().create()


private val httpClient : OkHttpClient by lazy 
    OkHttpClient.Builder().build()


private val retrofit : Retrofit by lazy 
    Retrofit.Builder()
        .baseUrl(BASE_URL)
        .client(httpClient)
        .addConverterFactory(GsonConverterFactory.create(gson))
        .build()


val apiService :  ApiService by lazy
    retrofit.create(ApiService::class.java)

ApiService.kt

interface ApiService 

@GET("tenant/searchAllWithPagesAndFilters")
fun getUsers(
    @Query("reservationEnabled") reservationEnabled:Boolean,
    @Query("page") page:Int,
    @Query("size") size:Int,
    @Query("sort") sort:String,
    @Query("direction") direction:String
): Call<MutableList<User>>

UserRepository.kt

object UserRepository 

fun getMutableLiveData(context: Context) : MutableLiveData<ArrayList<User>>

    val mutableLiveData = MutableLiveData<ArrayList<User>>()

    context.showProgressBar()

    ApiClient.apiService.getUsers(true,0,5,"order","ASC").enqueue(object : Callback<MutableList<User>> 
        override fun onFailure(call: Call<MutableList<User>>, t: Throwable) 
            hideProgressBar()
            Log.e("error", t.localizedMessage)
        

        override fun onResponse(
            call: Call<MutableList<User>>,
            response: Response<MutableList<User>>
        ) 
            hideProgressBar()
            val usersResponse = response.body()
            usersResponse?.let  mutableLiveData.value = it as ArrayList<User> 
        

    )

    return mutableLiveData

UserViewModel.kt

class UserViewModel(private val context: Context) : ViewModel() 

private var listData = MutableLiveData<ArrayList<User>>()

init
    val userRepository : UserRepository by lazy 
        UserRepository
    
    if(context.isInternetAvailable()) 
        listData = userRepository.getMutableLiveData(context)
    


fun getData() : MutableLiveData<ArrayList<User>>
    return listData

MainActivity.kt

class MainActivity : AppCompatActivity() 

private lateinit var listUsers: MutableList<User>
private lateinit var adapter: UsersAdapter

override fun onCreate(savedInstanceState: Bundle?) 
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    recycler_main.layoutManager = LinearLayoutManager(this@MainActivity)
    listUsers = mutableListOf<User>()
    adapter = UsersAdapter(this,
        listUsers
    )
    recycler_main.adapter = adapter

    val userViewModel = ViewModelProviders.of(this,UserViewModelFactory(this)).get(UserViewModel::class.java)
    userViewModel.getData().observe(this,object:Observer<ArrayList<User>>
        override fun onChanged(t: ArrayList<User>?) 
            listUsers.clear()
            t?.let  listUsers.addAll(it) 
            adapter.notifyDataSetChanged()
        

    )

来自 POSTMAN 的 API 响应


"content": [
    
        "id": "609d2d79be5f8e42d9c13e41",
        "name": "bagno-sirena-posillipo",
        "title": "Bagno Sirena Posillipo",
        "tenantName": "Bagno Sirena",
        "tenantCode": "BSI",
        "description": "E' uno dei siti balneari più antichi, inserito in un posto incantevole a ridosso del Palazzo Donn'Anna, in una piccola insenatura riparata e quindi usufruibile in tutti i mesi dell'anno per chi vuole in piena città trascorrere qualche ora di relax respirando aria di mare e conservare l'abbronzatura estiva.\nI gestori si stanno impegnando per migliorare i servizi della location.\nVorremmo condividere con tutti gli amanti del mare e della costa di Posillipo questa meraviglia che abbiamo.\nVeniteci a trovare e avrete modo di constatare questa bellezza.",
        "confirmBookingsRequired": false,
        "paymentRequired": true,
        "fee": 1.0,
        "foodFee": 0.5,
        "feePercentage": 0.02,
        "foodFeePercentage": 0.02,
        "percentage": true,
        "signInSignOnEnabled": true,
        "qrCodeValidation": true,
        "tenantImage": ,
        "tenantOtherImage": [],
        "type": "Beach",
        "enabledServices": [],
        "master": false,
        "comune": "Napoli",
        "comuneId": "063049",
        "address": 
            "address": "Via Posillipo, 357",
            "city": "Napoli",
            "province": "NA",
            "country": "Italia",
            "postalNumber": "80123",
            "phoneNumber": "081 769 2885",
            "web": "https://www.facebook.com/bagnosirenanapoli/",
            "email": "development@synclab.it"
        ,
        "reservationEnabled": true,
        "foodEnabled": true,
        "reservationWithoutMapButWithCart": false,
        "criteriaNumPlaces": ,
        "supportedServices": [
            
                "id": "5f04a23f968f9926b4b76746",
                "name": "Lettini",
                "description": "Lettini",
                "supported": true,
                "tenantTypes": []
            ,
            
                "id": "5f04a240968f9926b4b76747",
                "name": "Ombrelloni",
                "description": "Ombrelloni",
                "supported": true,
                "tenantTypes": []
            ,
            
                "id": "5f04a240968f9926b4b76748",
                "name": "Sdraio",
                "description": "Sdraio",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "5f04a240968f9926b4b76749",
                "name": "Parcheggio",
                "description": "Parcheggio",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "5f04a240968f9926b4b7674a",
                "name": "Lettoni",
                "description": "Lettoni",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "5f04a240968f9926b4b7674b",
                "name": "Accessibilita",
                "description": "Accesso disabili\n",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "5f04a240968f9926b4b7674c",
                "name": "Area_baby",
                "description": "Area baby",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "5f04a240968f9926b4b7674d",
                "name": "Ristorante",
                "description": "Ristorante",
                "supported": true,
                "tenantTypes": []
            ,
            
                "id": "5f04a240968f9926b4b7674e",
                "name": "Bar",
                "description": "Bar",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "5f04a240968f9926b4b7674f",
                "name": "Alcolici",
                "description": "Alcolici",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "5f04a240968f9926b4b76750",
                "name": "Gazebo",
                "description": "Gazebo",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "5f04a240968f9926b4b76751",
                "name": "Pagoda",
                "description": "Pagoda",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "5f04a240968f9926b4b76752",
                "name": "Wc",
                "description": "Wc",
                "supported": true,
                "tenantTypes": []
            ,
            
                "id": "60c72a1709e2081fa9b6d422",
                "name": "Wi-fi",
                "description": "Wi-fi",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "60c72a2509e2081fa9b6d423",
                "name": "Accesso_animali",
                "description": "Animali",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "60c72a2709e2081fa9b6d424",
                "name": "Animazione",
                "description": "Animazione",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "60c72a2a09e2081fa9b6d425",
                "name": "Cabine",
                "description": "Cabine",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "60c72a4109e2081fa9b6d426",
                "name": "Piscina",
                "description": "Piscina",
                "supported": false,
                "tenantTypes": []
            ,
            
                "id": "60ec61341dbc2d4ed0d130ff",
                "name": "Sedia_regista",
                "description": "Sedia regista",
                "supported": false,
                "searchable": true,
                "tenantTypes": []
            
        ],
        "types": [
            
                "typeId": "60c73af609e2081fa9b6d42a",
                "name": "Sassi",
                "description": "Sassi",
                "supported": false,
                "tenantTypes": []
            ,
            
                "typeId": "60c73af609e2081fa9b6d42b",
                "name": "Erba_sintetica",
                "description": "Erba sintetica",
                "supported": false,
                "tenantTypes": []
            ,
            
                "typeId": "60c73af609e2081fa9b6d42c",
                "name": "Molo",
                "description": "Molo",
                "supported": false,
                "tenantTypes": []
            ,
            
                "typeId": "60ccb0874107e97fccaac087",
                "name": "Spiaggia",
                "description": "Spiaggia",
                "supported": true,
                "tenantTypes": []
            ,
            
                "typeId": "60ccb0874107e97fccaac088",
                "name": "Erba_naturale",
                "description": "Erba naturale",
                "supported": false,
                "tenantTypes": []
            ,
            
                "typeId": "60ccb0874107e97fccaac089",
                "name": "Ciottoli",
                "description": "Ciottoli",
                "supported": false,
                "tenantTypes": []
            
        ],
        "targets": [
            
                "id": "60c73af609e2081fa9b6d42d",
                "name": "Famiglie",
                "description": "Famiglie",
                "supported": true,
                "tenantTypes": []
            ,
            
                "id": "60c73af609e2081fa9b6d42e",
                "name": "Coppie",
                "description": "Coppie",
                "supported": true,
                "tenantTypes": []
            ,
            
                "id": "60c73af609e2081fa9b6d42f",
                "name": "Ragazzi",
                "description": "Ragazzi",
                "supported": false,
                "tenantTypes": []
            
        ],
        "visible": true,
        "maxNumBookingGuests": 0,
        "numBookablePlaces": 0,
        "maxPlacesPerBooking": 0,
        "withoutLayout": false,
        "lastMinute": true,
        "upfront": false,
        "latitude": 40.8197859,
        "longitude": 14.2113269,
        "order": 1,
        "bookingUserDetailActive": false
    
],
"pageable": 
    "sort": 
        "sorted": true,
        "unsorted": false,
        "empty": false
    ,
    "pageNumber": 0,
    "pageSize": 1,
    "offset": 0,
    "paged": true,
    "unpaged": false
,
"last": true,
"totalElements": 1,
"totalPages": 1,
"sort": 
    "sorted": true,
    "unsorted": false,
    "empty": false
,
"first": true,
"number": 0,
"numberOfElements": 1,
"size": 1,
"empty": false

通过插件生成的数据类。（我就贴这个）

data class User(
@SerializedName("content")
val content: Content? = null,
@SerializedName("empty")
val empty: Boolean? = null,
@SerializedName("first")
val first: Boolean? = null,
@SerializedName("last")
val last: Boolean? = null,
@SerializedName("number")
val number: Int? = null,
@SerializedName("numberOfElements")
val numberOfElements: Int? = null,
@SerializedName("size")
val size: Int? = null,
@SerializedName("totalElements")
val totalElements: Int? = null,
@SerializedName("totalPages")
val totalPages: Int? = null

) : 可序列化

【问题讨论】：

这能回答你的问题吗？ Retrofit Expected BEGIN_OBJECT but was BEGIN_ARRAY 您期望响应中的用户列表 (Call<MutableList<User>>) 但 api 返回一个 json 对象。您可以在问题中添加您的 api 响应吗？ @IvanWooll 不，我在问这个问题之前已经在网上检查了所有内容 @ArpitShukla 我想我已经添加了它，请告诉我.. 提前谢谢你 @JonathanQuaranta 您在哪里有响应中的用户列表？您在Call<MutableList<User>> 中接受的那个 【参考方案1】：

您期望的数据类型不是服务器提供的。实际上，您的端点会返回一个 json 对象，而您需要一个用户列表。

您需要创建另一个包含用户列表的数据类。

如果您在创建数据类时迷失了方向，我建议您使用JsonToKotlin android Studio 扩展来轻松实现它们。

【讨论】：

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