我试图解析这样的JSON字符串

[
   {
      "updated_at":"2012-03-02 21:06:01",
      "fetched_at":"2012-03-02 21:28:37.728840",
      "description":null,
      "language":null,
      "title":"JOHN",
      "url":"http://rus.JOHN.JOHN/rss.php",
      "icon_url":null,
      "logo_url":null,
      "id":"4f4791da203d0c2d76000035",
      "modified":"2012-03-02 23:28:58.840076"
   },
   {
      "updated_at":"2012-03-02 14:07:44",
      "fetched_at":"2012-03-02 21:28:37.033108",
      "description":null,
      "language":null,
      "title":"PETER",
      "url":"http://PETER.PETER.lv/rss.php",
      "icon_url":null,
      "logo_url":null,
      "id":"4f476f61203d0c2d89000253",
      "modified":"2012-03-02 23:28:57.928001"
   }
]

变成一个对象列表。

List<ChannelSearchEnum> lcs = (List<ChannelSearchEnum>) new Gson().fromJson( jstring , ChannelSearchEnum.class);

这是我使用的一个对象类。

import com.google.gson.annotations.SerializedName;

public class ChannelSearchEnum {



@SerializedName("updated_at")
private String updated_at;

@SerializedName("fetched_at")
private String fetched_at;

@SerializedName("description")
private String description;

@SerializedName("language")
private String language;

@SerializedName("title")
private String title;

@SerializedName("url")
private String url;

@SerializedName("icon_url")
private String icon_url;

@SerializedName("logo_url")
private String logo_url;

@SerializedName("id")
private String id;

@SerializedName("modified")
private String modified;

public final String get_Updated_at() {
    return this.updated_at;
}

public final String get_Fetched_at() {
    return this.fetched_at;
}

public final String get_Description() {
    return this.description;
}

public final String get_Language() {
    return this.language;
}

public final String get_Title() {
    return this.title;
}

public final String get_Url() {
    return this.url;
}

public final String get_Icon_url() {
    return this.icon_url;
}

public final String get_Logo_url() {
    return this.logo_url;
}

public final String get_Id() {
    return this.id;
}

public final String get_Modified() {
    return this.modified;
}

        }

但这让我

com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2

有什么好办法吗?


当前回答

科特林:

var list=ArrayList<Your class name>()
val listresult: Array<YOUR CLASS NAME> = Gson().fromJson(
                YOUR JSON RESPONSE IN STRING,
                Array<Your class name>:: class.java)

list.addAll(listresult)

其他回答

在我的例子中是JSON字符串:

[{"category":"College Affordability",
  "uid":"150151",
  "body":"Ended more than $60 billion in wasteful subsidies for big banks and used the savings to put the cost of college within reach for more families.",
  "url":"http:\/\/www.whitehouse.gov\/economy\/middle-class\/helping middle-class-families-pay-for-college",
  "url_title":"ending subsidies for student loan lenders",
  "type":"Progress",
  "path":"node\/150385"}]

然后在recycleview中打印“category”和“url_title”

Datum.class

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Datum {
@SerializedName("category")
@Expose
private String category;
@SerializedName("uid")
@Expose
private String uid;
@SerializedName("url_title")
@Expose
private String urlTitle;

/**
 * @return The category
 */
public String getCategory() {
    return category;
}

/**
 * @param category The category
 */
public void setCategory(String category) {
    this.category = category;
}

/**
 * @return The uid
 */
public String getUid() {
    return uid;
}

/**
 * @param uid The uid
 */
public void setUid(String uid) {
    this.uid = uid;
}

/**
 * @return The urlTitle
 */
public String getUrlTitle() {
    return urlTitle;
}

/**
 * @param urlTitle The url_title
 */
public void setUrlTitle(String urlTitle) {
    this.urlTitle = urlTitle;
}

}

RequestInterface

import java.util.List;

import retrofit2.Call;
import retrofit2.http.GET;

/**
 * Created by Shweta.Chauhan on 13/07/16.
 */

public interface RequestInterface {

   @GET("facts/json/progress/all")
   Call<List<Datum>> getJSON();
}

DataAdapter

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by Shweta.Chauhan on 13/07/16.
 */

public class DataAdapter extends RecyclerView.Adapter<DataAdapter.MyViewHolder>{

private Context context;
private List<Datum> dataList;

public DataAdapter(Context context, List<Datum> dataList) {
    this.context = context;
    this.dataList = dataList;
}

@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.data,parent,false);
    return new MyViewHolder(view);
}

@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
    holder.categoryTV.setText(dataList.get(position).getCategory());
    holder.urltitleTV.setText(dataList.get(position).getUrlTitle());

}

@Override
public int getItemCount() {
    return dataList.size();
}

public class MyViewHolder extends RecyclerView.ViewHolder{

    public TextView categoryTV, urltitleTV;

    public MyViewHolder(View itemView) {
        super(itemView);
        categoryTV = (TextView) itemView.findViewById(R.id.txt_category);
        urltitleTV = (TextView)     itemView.findViewById(R.id.txt_urltitle);
    }
}
}

最后是MainActivity.java

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;

public class MainActivity extends AppCompatActivity {

private RecyclerView recyclerView;
private DataAdapter dataAdapter;
private List<Datum> dataArrayList;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initViews();
}

private void initViews(){
    recyclerView=(RecyclerView) findViewById(R.id.recycler_view);
    recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));
    loadJSON();
}

private void loadJSON(){
    dataArrayList = new ArrayList<>();
    Retrofit retrofit=new Retrofit.Builder().baseUrl("https://www.whitehouse.gov/").addConverterFactory(GsonConverterFactory.create()).build();
    RequestInterface requestInterface=retrofit.create(RequestInterface.class);
    Call<List<Datum>> call= requestInterface.getJSON();
    call.enqueue(new Callback<List<Datum>>() {
        @Override
        public void onResponse(Call<List<Datum>> call, Response<List<Datum>> response) {
            dataArrayList = response.body();
            dataAdapter=new DataAdapter(getApplicationContext(),dataArrayList);
            recyclerView.setAdapter(dataAdapter);
        }

        @Override
        public void onFailure(Call<List<Datum>> call, Throwable t) {
            Log.e("Error",t.getMessage());
        }
    });
}
}

问题是,您告诉Gson您有一个属于自己类型的对象。你不。你有一个自己类型的对象数组。你不能只是尝试这样的结果,并期望它神奇地工作;)

Gson的用户指南解释了如何处理这个问题:

https://github.com/google/gson/blob/master/UserGuide.md

这是可行的:

ChannelSearchEnum[] enums = gson.fromJson(yourJson, ChannelSearchEnum[].class);

但这样更好:

Type collectionType = new TypeToken<Collection<ChannelSearchEnum>>(){}.getType();
Collection<ChannelSearchEnum> enums = gson.fromJson(yourJson, collectionType);

解决方案

我正在使用截击库。我解析响应自动在凌空使用GSON


    [
            {
                "name": "Naruto: Shippuuden",
                "description": "It has been two and a half years since Naruto Uzumaki left Konohagakure, the Hidden Leaf Village, for intense training following events which fueled his desire to be stronger. Now Akatsuki, the mysterious organization of elite rogue ninja, is closing in on their grand plan which may threaten the safety of the entire shinobi world.",
                "Rating": "8.16",
                "episode": 500,
                "categorie":"Animation | Drama | Adventure",
                "studio":"Studio Pierrot",
                "img": "https://myanimelist.cdn-dena.com/images/anime/5/17407.jpg"
            },
            {
                "name": "One Piece",
                "description": "Gol D. Roger was known as the 'Pirate King',the strongest and most infamous being to have sailed the Grand Line. The capture and death of Roger by the World Government brought a change throughout the world. His last words before his death revealed the existence of the greatest treasure in the world, One Piece. It was this revelation that brought about the Grand Age of Pirates, men who dreamed of finding One Piece—which promises an unlimited amount of riches and fame—and quite possibly the pinnacle of glory and the title of the Pirate King.",
                "Rating": "8.54",
                "episode": 700,
                 "categorie":"Animation | Drama | Adventure",
                "studio":"Toei Animation",
                "img": "https://myanimelist.cdn-dena.com/images/anime/6/73245.jpg"
            }
        ]

2.这是我的模型


    public class DataResponse implements Serializable {
    
        @SerializedName("studio")
        private String studio;
    
        @SerializedName("img")
        private String img;
    
        @SerializedName("categorie")
        private String categorie;
    
        @SerializedName("Rating")
        private String rating;
    
        @SerializedName("name")
        private String name;
    
        @SerializedName("description")
        private String description;
    
        @SerializedName("episode")
        private int episode;
    
        public void setStudio(String studio){
            this.studio = studio;
        }
    
        public String getStudio(){
            return studio;
        }
    
        public void setImg(String img){
            this.img = img;
        }
    
        public String getImg(){
            return img;
        }
    
        public void setCategorie(String categorie){
            this.categorie = categorie;
        }
    
        public String getCategorie(){
            return categorie;
        }
    
        public void setRating(String rating){
            this.rating = rating;
        }
    
        public String getRating(){
            return rating;
        }
    
        public void setName(String name){
            this.name = name;
        }
    
        public String getName(){
            return name;
        }
    
        public void setDescription(String description){
            this.description = description;
        }
    
        public String getDescription(){
            return description;
        }
    
        public void setEpisode(int episode){
            this.episode = episode;
        }
    
        public int getEpisode(){
            return episode;
        }
    
        @Override
        public String toString(){
            return 
                "Response{" + 
                "studio = '" + studio + '\'' + 
                ",img = '" + img + '\'' + 
                ",categorie = '" + categorie + '\'' + 
                ",rating = '" + rating + '\'' + 
                ",name = '" + name + '\'' + 
                ",description = '" + description + '\'' + 
                ",episode = '" + episode + '\'' + 
                "}";
            }
    }

我的API方法

define globle

private List<DataResponse> dataResponses = new ArrayList<>();


    private void volleyAutomation(String url) {
            JSONArray array = new JSONArray();
            JsonArrayRequest request_json = new JsonArrayRequest(Request.Method.GET, url, array,
                    new Response.Listener<JSONArray>() {
                        @Override
                        public void onResponse(JSONArray response) {
    
                            GsonBuilder gsonBuilder = new GsonBuilder();
                            Gson gson = gsonBuilder.create();
                           dataResponses = Arrays.asList(gson.fromJson(response.toString(), DataResponse[].class));
    
                            rvList(dataResponses);
                            Log.d("respknce___", String.valueOf(dataResponses.size()));
                        }
                    }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError volleyError) {
    
                }
            });
            RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());
            requestQueue.add(request_json);
        }

根据GSON用户指南,您不能。

集合的局限性 可以序列化任意对象的集合,但不能从它反序列化。因为用户无法指示结果对象的类型

科特林:

var list=ArrayList<Your class name>()
val listresult: Array<YOUR CLASS NAME> = Gson().fromJson(
                YOUR JSON RESPONSE IN STRING,
                Array<Your class name>:: class.java)

list.addAll(listresult)