Java 将JSONObject转换为JSONArray时出现的问题

因此，我的应用程序有一个小错误，阻止我进行货币转换

03-01 03:56:05.810 18853-18870/com.example.justin.currencyconverter20 D/JSON Parser: result: {"base":"SGD","date":"2016-02-29","rates":{"AUD":0.99576,"BGN":1.2762,"BRL":2.8316,"CAD":0.96359,"CHF":0.71217,"CNY":4.6559,"CZK":17.655,"DKK":4.868,"GBP":0.51276,"HKD":5.5237,"HRK":4.9764,"HUF":203.11,"IDR":9500.4,"ILS":2.7769,"INR":48.537,"JPY":80.352,"KRW":879.31,"MXN":12.92,"MYR":2.9931,"NOK":6.2018,"NZD":1.0804,"PHP":33.68,"PLN":2.8413,"RON":2.9205,"RUB":53.927,"SEK":6.0828,"THB":25.336,"TRY":2.1059,"USD":0.71047,"ZAR":11.391,"EUR":0.65253}}
03-01 03:56:05.811 18853-18870/com.example.justin.currencyconverter20 E/JSON Parser: Error parsing data org.json.JSONException: Value {"AUD":0.99576,"BGN":1.2762,"BRL":2.8316,"CAD":0.96359,"CHF":0.71217,"CNY":4.6559,"CZK":17.655,"DKK":4.868,"GBP":0.51276,"HKD":5.5237,"HRK":4.9764,"HUF":203.11,"IDR":9500.4,"ILS":2.7769,"INR":48.537,"JPY":80.352,"KRW":879.31,"MXN":12.92,"MYR":2.9931,"NOK":6.2018,"NZD":1.0804,"PHP":33.68,"PLN":2.8413,"RON":2.9205,"RUB":53.927,"SEK":6.0828,"THB":25.336,"TRY":2.1059,"USD":0.71047,"ZAR":11.391,"EUR":0.65253} at rates of type org.json.JSONObject cannot be converted to JSONArray

这是我的JSONParser：

package com.example.justin.currencyconverter20;

import android.util.Log;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.HashMap;

public class JSONParser {

    String charset = "UTF-8";
    HttpURLConnection conn;
    DataOutputStream wr;
    StringBuilder result;
    URL urlObj;
    JSONArray Obj = null;
    StringBuilder sbParams;
    String paramsString;


    public JSONArray makeHttpRequest(String url, String method) {

        int i = 0;

        if(method.equals("GET")){

            try {
                urlObj = new URL(url);

                conn = (HttpURLConnection) urlObj.openConnection();

                conn.setDoOutput(false);

                conn.setRequestMethod("GET");

                conn.setConnectTimeout(15000);

                conn.connect();

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

        }

        try {
            //Receive the response from the server
            InputStream in = new BufferedInputStream(conn.getInputStream());
            BufferedReader reader = new BufferedReader(new InputStreamReader(in));
            result = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                result.append(line);
            }

            Log.d("JSON Parser", "result: " + result.toString());

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

        conn.disconnect();

        // try parse the string to a JSON object
        try {
            JSONObject jObj = new JSONObject(result.toString());
            Obj = jObj.getJSONArray("rates");
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON Object
        return Obj;
    }
}

任何帮助都将不胜感激。注意：我对这一点还是相当陌生的，所以如果可能，请简化，非常感谢

编辑： 好的，我使用的JSON api是，我使用www.jsonlint.com将其转换为JSON格式，转换为以下JSON：

{
    "base": "SGD",
    "date": "2016-02-29",
    "rates": {
        "AUD": 0.99576,
        "BGN": 1.2762,
        "BRL": 2.8316,
        "CAD": 0.96359,
        "CHF": 0.71217,
        "CNY": 4.6559,
        "CZK": 17.655,
        "DKK": 4.868,
        "GBP": 0.51276,
        "HKD": 5.5237,
        "HRK": 4.9764,
        "HUF": 203.11,
        "IDR": 9500.4,
        "ILS": 2.7769,
        "INR": 48.537,
        "JPY": 80.352,
        "KRW": 879.31,
        "MXN": 12.92,
        "MYR": 2.9931,
        "NOK": 6.2018,
        "NZD": 1.0804,
        "PHP": 33.68,
        "PLN": 2.8413,
        "RON": 2.9205,
        "RUB": 53.927,
        "SEK": 6.0828,
        "THB": 25.336,
        "TRY": 2.1059,
        "USD": 0.71047,
        "ZAR": 11.391,
        "EUR": 0.65253
    }
}

---

JSON字符串中没有JSON数组。因此，您必须获得另一个JSON对象

JSONObject ratesObject = jObj.getJSONIObject("rates");

然后您可以很容易地得到如下值

Double aud = ratesObject.getDouble("AUD");
Double bgn = ratesObject.getDouble("BGN");

---

如果费率为数组，则代码如下：

 JSONArray Objs = jObj.getJSONArray("rates");

但字符串中有一个JSON对象“rates”：

因此，请使用下面的代码：

JSONObe Obj = jObj.getJSONObject("rates");

您可以通过以下方式访问Obj的任何字段：

Double php = Obj.getDouble("PHP");

或获取字符串类型：

String php = Obj.getString("PHP");

试试这个

public JSONObject makeHttpRequest(String url, String method) {
 try {
            JSONObject jObj = new JSONObject(result.toString());
             JSONObject jObj2 = jObj.getJSONObject("rates");
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }   
return jObj2; 
}

---

首先，在尝试解析Json格式的数据时，应该能够区分JSONObject和JSONArray。这方面有很多工具，但我建议：

其次，可以使用之类的库将json格式的数据转换为java POJO类和对象。为此，您可以使用以下工具，该工具将生成使用Gson需要创建的等效POJO类：

最后，您应该在代码中进行以下更改以删除错误：

JSONObject ratesObject = jObj.getJSONIObject("rates");
String aud = ratesObject.getString("AUD");

---

请发布您从服务器获得的json数据，如错误消息所示，json字符串以

{

开头，这意味着它是一个json对象而不是数组，您需要将其解析为一个对象而不是数组，rates是json对象而不是数组使用json数据进行更新//尝试将字符串解析为json对象重试{JSONObject jObj=new JSONObject（result.toString（））；Obj=jObj.getJSONArray（“rates”）；}catch（JSONException e）{Log.e（“JSON解析器”，“错误解析数据”+e.toString（））；}在这个try blockHmm中，在这样做之后，我得到了这个错误：03-01 04:37:22.960 19287-19335/com.example.justin.currencyconverter20 E/JSON解析器：错误解析数据org.JSON.JSONException:No value for RUNyes当然……因为JSON中没有键“RUN”。我看到的是“RON”。

JSONObject ratesObject = jObj.getJSONIObject("rates");
String aud = ratesObject.getString("AUD");