我只想出于测试目的而显示JSON中的值，但实际上什么也没收到。哪里有问题？ Utils中的链接肯定是正确的，我已经在浏览器上运行了它，一切都很好。
这是代码
实用程序类
public class WeatherUtils {
public WeatherUtils(){}
public static ArrayList<Weather> getHourlyData (double minTemp, double maxTemp, double currentTemp, double airPressure){
ArrayList<Weather> weatherList = new ArrayList<>();
try {
JSONObject reader = new JSONObject("https://api.openweathermap.org/data/2.5/forecast?q=London,us&units=metric&appid=ID...");
JSONArray array = reader.getJSONArray("list");
for (int i = 0; i<array.length(); i++){
JSONObject secondReader = array.getJSONObject(i);
JSONObject dataObject = secondReader.getJSONObject("main");
for (int j = 0; j<dataObject.length(); j++){
currentTemp = dataObject.getDouble("temp");
minTemp = dataObject.getDouble("temp_min");
maxTemp = dataObject.getDouble("temp_max");
airPressure = dataObject.getDouble("pressure");
}
weatherList.add(new Weather(currentTemp,minTemp,maxTemp,airPressure));
}
} catch (JSONException e) {
e.printStackTrace();
}
return weatherList;
}
}
MainActivity 将a，b，c，d加倍；
a = 0.0;
b = 0.0;
c = 0.0;
d = 0.0;
ArrayList<Weather> weathers = WeatherUtils.getHourlyData(a,b,c,d);
System.out.println(weathers);
JSON结构
{
"cod": "200",
"message": 0.0074,
"cnt": 40,
"list": [
{
"dt": 1559131200,
"main": {
"temp": 22.1,
"temp_min": 21.32,
"temp_max": 22.1,
"pressure": 1012.31,
"sea_level": 1012.31,
"grnd_level": 976.84,
"humidity": 92,
"temp_kf": 0.78
},
"weather": [
{
"id": 500,
"main": "Rain",
"description": "light rain",
"icon": "10d"
}
],
"clouds": {
"all": 89
},
"wind": {
"speed": 3.08,
"deg": 213.025
},
"rain": {
"3h": 0.875
},
"sys": {
"pod": "d"
},
"dt_txt": "2019-05-29 12:00:00"
},
{
当然，还有更多数据。我发布了一个“块”
该如何解决？
答案 0 :(得分：0)
好吧，考虑到您只想“测试” json解析，您几乎没有选择，但是让我们来看一个简单的选择。但是首先，我会说要提取解析器并将其放在自己的类/方法中，以便测试变得更加容易，就像这样：
public class WeatherUtils {
public WeatherUtils(){}
public static ArrayList<Weather> getHourlyData (double minTemp, double maxTemp, double currentTemp, double airPressure){
final ArrayList<Weather> weatherList = new ArrayList<>();
try {
final JSONObject response = httpCall();
weatherList = mapWeatherResponse(response);
} catch (JSONException e) {
e.printStackTrace();
}
return weatherList;
}
public static List<Weather> mapWeatherResponse(JSONObject reader){
final ArrayList<Weather> weatherList = new ArrayList<>();
JSONArray array = reader.getJSONArray("list");
for (int i = 0; i<array.length(); i++){
JSONObject secondReader = array.getJSONObject(i);
JSONObject dataObject = secondReader.getJSONObject("main");
for (int j = 0; j<dataObject.length(); j++){
currentTemp = dataObject.getDouble("temp");
minTemp = dataObject.getDouble("temp_min");
maxTemp = dataObject.getDouble("temp_max");
airPressure = dataObject.getDouble("pressure");
}
weatherList.add(new Weather(currentTemp,minTemp,maxTemp,airPressure));
}
}
}
您可以这样创建一个junit测试：
public class WeatherUtilsTest {
@Test
public void parserResponseTEst() {
final List<String> expectedResponse = new ArrayList<>();
//fill the expectedResponse with the correspondent values
final String json = "{\n" +
" \"cod\": \"200\",\n" +
" \"message\": 0.0074,\n" +
" \"cnt\": 40,\n" +
" \"list\": [\n" +
" {\n" +
" \"dt\": 1559131200,\n" +
" \"main\": {\n" +
" \"temp\": 22.1,\n" +
" \"temp_min\": 21.32,\n" +
" \"temp_max\": 22.1,\n" +
" \"pressure\": 1012.31,\n" +
" \"sea_level\": 1012.31,\n" +
" \"grnd_level\": 976.84,\n" +
" \"humidity\": 92,\n" +
" \"temp_kf\": 0.78\n" +
" },\n" +
" \"weather\": [\n" +
" {\n" +
" \"id\": 500,\n" +
" \"main\": \"Rain\",\n" +
" \"description\": \"light rain\",\n" +
" \"icon\": \"10d\"\n" +
" }\n" +
" ],\n" +
" \"clouds\": {\n" +
" \"all\": 89\n" +
" },\n" +
" \"wind\": {\n" +
" \"speed\": 3.08,\n" +
" \"deg\": 213.025\n" +
" },\n" +
" \"rain\": {\n" +
" \"3h\": 0.875\n" +
" }\n" +
" }]\n" +
" }";
final List<String> response = WeatherUtils.mapWeatherResponse(new JSONObject(json));
assertEquals(expectedResponse, response);
}
}
您正在执行的JSONObject解析器没有任何问题。您提到在Utils中使用的链接是正确的，在浏览器中测试该链接是否正确，邮递员，失眠了吗？
OBS JSONObject reader = new JSONObject("https://api...");不会获取任何内容，您在这里所做的就是根据给定的JSONObject（即“ https：//”）创建一个String。 ...”。要获取数据，您需要实现一些http客户端。这是一个示例https://stackoverflow.com/a/4457526/761668
答案 1 :(得分：0)
您没有从服务器获得响应，而是尝试使用URL初始化JSONObject。
要检索它，您应该替换此行：
JSONObject reader = new JSONObject("https://api.openweathermap.org/data/2.5/forecast?q=London,us&units=metric&appid=ID...");
使用以下代码：
HttpURLConnection conn = null;
String data = null;
try {
conn = (HttpURLConnection) new URL("https://api.openweathermap.org/data/2.5/forecast?q=London,us&units=metric&appid=ID...").openConnection();
conn.setRequestMethod("GET");
conn.connect();
BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
StringBuilder sb = new StringBuilder();
String line;
while ((line = br.readLine()) != null) {
sb.append(line + "\n");
}
br.close();
data = sb.toString();
} catch (Exception e) {
// do something
} finally {
if (conn != null) {
try {
conn.disconnect();
} catch (Exception ex) {
// do something
}
}
}
JSONObject reader = new JSONObject(data);
此代码将从端点检索JSON对象，并将其转换为String对象。然后，您可以使用它创建一个JSONObject。