从 api 数组或矩阵 java ZC31B32364CE19CA8FCD150A417ECCE5 中提取 json 数据

Question

我无法从此 json 中提取数据。 我相信这是因为它是一个数组。 我读过它，但我没有找到任何关于这个案例的具体内容。

每次关闭 {} 时，我只需要单独获取这些值。

例如：结果 [0].getLoterias();

== 瞬间

连接正常，我只是无法提取数据。

httpservice2.java

package br.com.matheuscastiglioni.blog.requisicao_http.service;

import android.os.AsyncTask;

import com.google.gson.Gson;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Scanner;

import br.com.matheuscastiglioni.blog.requisicao_http.model.CEP2;

public class HttpService2 extends AsyncTask<Void, Void, CEP2> {


    private final String cep;
    private final String token;

    public HttpService2(String cep, String token) {
        this.cep = token;
        this.token = cep;

    }

    @Override
    protected CEP2 doInBackground(Void... voids) {
        StringBuilder resposta = new StringBuilder();



            try {
                URL url = new URL( "A" + this.cep + "&token=" + this.token);

                HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                connection.setRequestMethod("GET");
                connection.setRequestProperty("Content-type", "application/json");
                connection.setRequestProperty("Accept", "application/json");
                connection.setDoOutput(true);
                connection.setConnectTimeout(5000);
                connection.connect();

                Scanner scanner = new Scanner(url.openStream());
                while (scanner.hasNext()) {
                    resposta.append(scanner.next());
                }



            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }



            return new Gson().fromJson(resposta.toString(), CEP2.class);
    }



}

Main3Activity.java：

package br.com.matheuscastiglioni.blog.requisicao_http;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import java.util.concurrent.ExecutionException;

import br.com.matheuscastiglioni.blog.requisicao_http.model.CEP2;
import br.com.matheuscastiglioni.blog.requisicao_http.service.HttpService2;

public class Main3Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main3);


        final TextView resposta = findViewById(R.id.etMain_resposta2);
        final TextView cep = findViewById(R.id.etMain_resposta3);
        final TextView token = findViewById(R.id.etMain_resposta4);
        Bundle extras = getIntent().getExtras();
        String respostatoken = extras.getString("token");
        String respostaid = extras.getString("id");

        cep.setText(respostaid);
        token.setText(respostatoken);
//alert(cep.getText().toString() + token.getText().toString());
          try {
              CEP2 retorno = new HttpService2(cep.getText().toString(), token.getText().toString()).execute().get();
              String loteria = retorno.getIdloteria();
            resposta.setText(loteria);
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }

    }

    private void alert(String s) {
        Toast.makeText(this,s,Toast.LENGTH_LONG).show();
    }
}

CEP2.java：

package br.com.matheuscastiglioni.blog.requisicao_http.model;



public class CEP2 {


    private String idloteria;

    public String getIdloteria() {
        return idloteria;
    }

    public void setIdloteria(String idloteria) {
        this.idloteria = idloteria;
    }



}

目前：

我变了

return new Gson().fromJson(resposta.toString(), CEP2.class);

每

Type cep2ListType = new TypeToken<ArrayList<CEP2>>(){}.getType();
List<CEP2> cep2List = new Gson().fromJson(resposta.toString(), cep2ListType);
return cep2List;

httpsservic2 新：

package br.com.matheuscastiglioni.blog.requisicao_http.service;

import android.os.AsyncTask;

import com.google.gson.Gson;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Scanner;

import br.com.matheuscastiglioni.blog.requisicao_http.model.CEP2;

public class HttpService2 extends AsyncTask<Void, Void, CEP2> {


    private final String cep;
    private final String token;

    public HttpService2(String cep, String token) {
        this.cep = token;
        this.token = cep;

    }

    @Override
    protected CEP2 doInBackground(Void... voids) {
        StringBuilder resposta = new StringBuilder();



            try {
                URL url = new URL( "A" + this.cep + "&token=" + this.token);

                HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                connection.setRequestMethod("GET");
                connection.setRequestProperty("Content-type", "application/json");
                connection.setRequestProperty("Accept", "application/json");
                connection.setDoOutput(true);
                connection.setConnectTimeout(5000);
                connection.connect();

                Scanner scanner = new Scanner(url.openStream());
                while (scanner.hasNext()) {
                    resposta.append(scanner.next());
                }



            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }



               Type cep2ListType = new TypeToken<ArrayList<CEP2>>(){}.getType();
        List<CEP2> cep2List = new Gson().fromJson(resposta.toString(), cep2ListType);
        return cep2List;
    }



}

我需要从 doinbackground 更改返回但是，我迷路了

Answer 1

看来您只想要响应中的 idloteria 应该没问题。 但是正如你所说的它是一个数组，它应该被解析为一个数组或一个列表。

这：

return new Gson().fromJson(resposta.toString(), CEP2.class);

应该

Type cep2ListType = new TypeToken<ArrayList<CEP2>>(){}.getType();
List<CEP2> cep2List = new Gson().fromJson(resposta.toString(), cep2ListType);
return cep2List;

如果您希望将响应解析为列表。

另一种可能性是将数据解析为数组：

CEP2[] cep2Array = new Gson().fromJson(resposta.toString(), CEP2[].class);
return cep2Array;

并且您需要根据您选择的响应类型更改 doInBackground 的返回。

让我们选择返回一个列表。 在这种情况下，将AsyncTask<Void, Void, CEP2>更改为AsyncTask<Void, Void, List<CEP2>>并将protected CEP2 doInBackground为protected List<CEP2> doInBackground 。 返回的列表将在 onPostExecute 参数onPostExecute(List<CEP2> cep2List)中接收。 在这个 onPostExecute 中，您可以保存列表、打印它或对接收到的数据做任何您想做的事情。

但请记住， AsyncTask 在 API 级别 R 中已弃用。 建议改用标准 java.util.concurrent 或 Kotlin 并发实用程序。