为什么 JSON 问题让我困惑：JSONObject 文本必须以字符 1 处的“{”开头

Question

我使用谷歌地图 API 从谷歌地图 API 获取 GPS 坐标。我使用与我的老师代码几乎相似的代码，用于使用 api 中的 JSON。他使用来自 darksky 的 api，我使用来自谷歌地图的 API。

我的代码：

package com.company;

import org.json.JSONException;

import org.json.JSONObject;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.net.URL;

import java.nio.charset.Charset;

public class MyCoorGiver {

public final String API_URL = "https://maps.googleapis.com/maps/api/geocode/json?address=";

private String cityName;

private final String apiKey = "&key=";

private String fullUrl;

private String rawData;

JSONObject jsonObject;

private double lat;

private double lng;

public String getFullUrl() {

    return fullUrl;

}

public MyCoorGiver(String cityName) {

    this.cityName = cityName;

    this.fullUrl = this.API_URL + cityName + this.apiKey;

}

private JSONObject readFromJsonUrl() throws IOException, JSONException {

    InputStream is = new URL(this.fullUrl).openStream();

    BufferedReader br = new BufferedReader(new InputStreamReader(is, Charset.forName("UTF-8")));

    String jsonText = readAll(br);

    jsonObject = new JSONObject(jsonText);

    return jsonObject;

}

    public String readAll(BufferedReader br) throws IOException {

        StringBuilder sb = new StringBuilder();

        int cp;

        while((cp = br.read()) != -1){

            sb.append(cp);

        }

        rawData = sb.toString();

        return sb.toString();

    }

    public String getRaw(){

        return rawData;

    }

    private double getLat() throws IOException, JSONException {

        JSONObject myData = readFromJsonUrl();

        JSONObject location = myData.getJSONObject("location");

        double lat = location.getDouble("lat");

        return lat;

    }

    private double getLng() throws IOException, JSONException {

        JSONObject myData = readFromJsonUrl();

        JSONObject location = myData.getJSONObject("location");

        double lng = location.getDouble("lng");

        return lng;

    }

Answer 1

UPD2： [表示数组，{在JSON语法中表示对象。试试。private double getLat() throws IOException, JSONException {        JSONObject myData = readFromJsonUrl();        JSONArray results = myData.getJSONArray("results");        JSONObject geometry = results.getJSONObject(0).getJSONObject("geometry");        JSONObject location = geometry.getJSONObject("location");        double lat = location.getDouble("lat");        return lat;    }UPD：您应该使用readLine()方法而不是read()，尝试更改您的代码，如下所示。public String readAll(BufferedReader br) throws IOException {        StringBuilder sb = new StringBuilder();        String cp;        while ((cp = br.readLine()) != null) {            sb.append(cp);        }        return sb.toString();    }您可以jsonText在控制台中打印以查看 JSON 语法是否正确。也许你可以尝试使用这段代码。private JSONObject readFromJsonUrl() throws IOException, JSONException {    InputStream is = new URL(this.fullUrl).openStream();    BufferedReader br = new BufferedReader(new InputStreamReader(is, Charset.forName("UTF-8")));    String jsonText = readAll(br);    //jsonObject = new JSONObject(jsonText);    ObjectMapper objectMapper = new ObjectMapper();    JSONObject jsonObject = objectMapper.readValue(jsonText, JSONObject.class);    return jsonObject;}