通過您所提供的鏈接訪問當前JSON的反應似乎有一些設計問題或懷疑他們。我會在這裏發表JSON爲了不讓它失去了在未來：
{
"weather": {
"forecast3hours": [
{
"grid": {
"city": "충북",
"county": "충주시",
"village": "목행동",
"latitude": "37.0135600000",
"longitude": "127.9036500000"
},
"lightning1hour": "0",
"timeRelease": "2017-02-24 16:30:00",
"wind": {
"wspd2hour": "3.10",
"wdir1hour": "179.00",
"wspd1hour": "4.20",
"wdir2hour": "176.00",
"wdir3hour": "",
"wspd3hour": "",
"wdir4hour": "",
"wspd4hour": ""
},
"precipitation": {
"sinceOntime1hour": "0.00",
"type1hour": "0",
"sinceOntime2hour": "0.00",
"type2hour": "0",
"sinceOntime3hour": "",
"type3hour": "",
"sinceOntime4hour": "",
"type4hour": ""
},
"sky": {
"code1hour": "SKY_V01",
"name1hour": "맑음",
"code2hour": "SKY_V01",
"name2hour": "맑음",
"code3hour": "",
"name3hour": "",
"code4hour": "",
"name4hour": ""
},
"temperature": {
"temp1hour": "3.20",
"temp2hour": "2.00",
"temp3hour": "",
"temp4hour": ""
},
"humidity": {
"rh1hour": "41.00",
"rh2hour": "50.00",
"rh3hour": "",
"rh4hour": ""
},
"lightning2hour": "0",
"lightning3hour": "",
"lightning4hour": ""
}
]
},
"common": {
"alertYn": "N",
"stormYn": "N"
},
"result": {
"code": 9200,
"requestUrl": "/weather/forecast/3hours?lon=127.9259&lat=36.991&version=1&appKey=4ce0462a-3884-30ab-ab13-93efb1bc171f",
"message": "성공"
}
}
從我的角度來看，他們是：
- 沒有數組，但是人爲索引對象鍵（這就是你的問題的主題）。
- 可能爲
null值的空字符串而不是null s或僅從響應中排除。
- 幾乎所有的值都表示爲字符串文字，即使它們看起來不是字符串。
- 大概布爾值似乎是標有
Yn後綴，並且使用分別與"Y"限定"N"和truefalse。
這就是爲什麼自動POJO發電機可能無法對付它，因爲他們可能不檢測「真正的」類型的特定JSON字符串值的最佳方式，而且他們無法生成自定義解串器。不確定爲什麼它是這樣設計的，但是您可以設計自定義映射，使其更具編程友好性，並對其進行更多的控制。
final class Response {
final Weather weather = null;
final Common common = null;
final Result result = null;
@Override
public String toString() {
return new StringBuilder("Response{")
.append("weather=").append(weather)
.append(", common=").append(common)
.append(", result=").append(result)
.append('}').toString();
}
}
final class Weather {
final List<Forecast> forecast3hours = null;
@Override
public String toString() {
return new StringBuilder("Weather{")
.append("forecast3hours=").append(forecast3hours)
.append('}').toString();
}
}
final class Forecast {
final Grid grid;
final Date timeRelease;
final List<Integer> lightnings;
final List<Wind> winds;
final List<Precipitation> precipitations;
final List<Sky> skies;
final List<Float> temperatures;
final List<Float> humidities;
Forecast(final Grid grid, final Date timeRelease, final List<Integer> lightnings, final List<Wind> winds, final List<Precipitation> precipitations,
final List<Sky> skies, final List<Float> temperatures, final List<Float> humidities) {
this.grid = grid;
this.timeRelease = timeRelease;
this.lightnings = lightnings;
this.winds = winds;
this.precipitations = precipitations;
this.skies = skies;
this.temperatures = temperatures;
this.humidities = humidities;
}
@Override
public String toString() {
return new StringBuilder("Forecast{")
.append("grid=").append(grid)
.append(", timeRelease=").append(timeRelease)
.append(", lightnings=").append(lightnings)
.append(", winds=").append(winds)
.append(", precipitations=").append(precipitations)
.append(", skies=").append(skies)
.append(", temperatures=").append(temperatures)
.append(", humidities=").append(humidities)
.append('}').toString();
}
}
final class Grid {
final String city = null;
final String county = null;
final String village = null;
final double latitude = Double.valueOf(0); // disable inlining the primitive double 0
final double longitude = Double.valueOf(0); // disable inlining the primitive double 0
@Override
public String toString() {
return new StringBuilder("Grid{")
.append("city='").append(city).append('\'')
.append(", county='").append(county).append('\'')
.append(", village='").append(village).append('\'')
.append(", latitude=").append(latitude)
.append(", longitude=").append(longitude)
.append('}').toString();
}
}
final class Wind {
final float speed;
final float direction;
Wind(final float speed, final float direction) {
this.speed = speed;
this.direction = direction;
}
@Override
public String toString() {
return new StringBuilder("Wind{")
.append("speed=").append(speed)
.append(", direction=").append(direction)
.append('}').toString();
}
}
final class Precipitation {
final float sinceOntime;
final int type;
Precipitation(final float sinceOntime, final int type) {
this.sinceOntime = sinceOntime;
this.type = type;
}
@Override
public String toString() {
return new StringBuilder("Precipitation{")
.append("sinceOntime='").append(sinceOntime).append('\'')
.append(", type=").append(type)
.append('}').toString();
}
}
final class Sky {
final String code;
final String name;
Sky(final String code, final String name) {
this.code = code;
this.name = name;
}
@Override
public String toString() {
return new StringBuilder("Sky{")
.append("code='").append(code).append('\'')
.append(", name='").append(name).append('\'')
.append('}').toString();
}
}
final class Common {
@SerializedName("alertYn")
@JsonAdapter(YnToBooleanJsonDeserializer.class)
final boolean alert = Boolean.valueOf(false); // disable inlining the primitive boolean false
@SerializedName("stormYn")
@JsonAdapter(YnToBooleanJsonDeserializer.class)
final boolean storm = Boolean.valueOf(false); // disable inlining the primitive boolean false
@Override
public String toString() {
return new StringBuilder("Common{")
.append("alert=").append(alert)
.append(", storm=").append(storm)
.append('}').toString();
}
}
final class Result {
final int code = Integer.valueOf(0); // disable inlining the primitive int 0
final String requestUrl = null;
final String message = null;
@Override
public String toString() {
return new StringBuilder("Result{")
.append("code=").append(code)
.append(", requestUrl='").append(requestUrl).append('\'')
.append(", message='").append(message).append('\'')
.append('}').toString();
}
}
一些映射的顯式的構造 - 這樣的對象必須手動自定義解串器被實例化。如果沒有提供構造函數，那麼Gson就可以自己處理這種映射，只需要有足夠的信息來說明如何對一個特定的對象進行反序列化。
由於應以非標準方式解析數據，因此可以實施一些自定義的反序列化器。以下類型的適配器分別將"Y"和"N"轉換爲true和false。
final class YnToBooleanJsonDeserializer
implements JsonDeserializer<Boolean> {
// Gson will instantiate this adapter itself
private YnToBooleanJsonDeserializer() {
}
@Override
public Boolean deserialize(final JsonElement jsonElement, final Type type, final JsonDeserializationContext context)
throws JsonParseException {
final String rawFlag = jsonElement.getAsString();
switch (rawFlag) {
case "N":
return false;
case "Y":
return true;
default:
throw new JsonParseException("Can't parse: " + rawFlag);
}
}
}
下JsonDeserializer嘗試檢測xxx<N>hour式的按鍵使用正則表達式，並提取<N>指數構建構建Forecast實例所需的列表。請注意，它可以解析任意大小的「列表」（JSON中的）。
final class ForecastJsonDeserializer
implements JsonDeserializer<Forecast> {
// This deserializer does not hold any state and can be instantiated once per application life-cycle.
private static final JsonDeserializer<Forecast> forecastJsonDeserializer = new ForecastJsonDeserializer();
private ForecastJsonDeserializer() {
}
static JsonDeserializer<Forecast> getForecastJsonDeserializer() {
return forecastJsonDeserializer;
}
@Override
public Forecast deserialize(final JsonElement jsonElement, final Type type, final JsonDeserializationContext context)
throws JsonParseException {
final JsonObject jsonObject = jsonElement.getAsJsonObject();
return new Forecast(
context.deserialize(jsonObject.get("grid"), Grid.class),
context.deserialize(jsonObject.get("timeRelease"), Date.class),
lightningsExtractor.parseList(jsonObject),
windsExtractor.parseList(jsonObject.get("wind").getAsJsonObject()),
precipitationsExtractor.parseList(jsonObject.get("precipitation").getAsJsonObject()),
skiesExtractor.parseList(jsonObject.get("sky").getAsJsonObject()),
temperaturesExtractor.parseList(jsonObject.get("temperature").getAsJsonObject()),
humiditiesExtractor.parseList(jsonObject.get("humidity").getAsJsonObject())
);
}
private static final AbstractExtractor<Integer> lightningsExtractor = new AbstractExtractor<Integer>(compile("lightning(\\d)hour")) {
@Override
protected Integer parse(final int index, final JsonObject jsonObject) {
final String rawLightning = jsonObject.get("lightning" + index + "hour").getAsString();
if (rawLightning.isEmpty()) {
return null;
}
return parseInt(rawLightning);
}
};
private static final AbstractExtractor<Wind> windsExtractor = new AbstractExtractor<Wind>(compile("(?:wdir|wspd)(\\d)hour")) {
@Override
protected Wind parse(final int index, final JsonObject jsonObject) {
String rawSpeed = jsonObject.get("wspd" + index + "hour").getAsString();
String rawDirection = jsonObject.get("wdir" + index + "hour").getAsString();
if (rawSpeed.isEmpty() && rawDirection.isEmpty()) {
return null;
}
return new Wind(parseFloat(rawSpeed), parseFloat(rawDirection));
}
};
private static final AbstractExtractor<Precipitation> precipitationsExtractor = new AbstractExtractor<Precipitation>(compile("(?:sinceOntime|type)(\\d)hour")) {
@Override
protected Precipitation parse(final int index, final JsonObject jsonObject) {
final String rawSinceOntime = jsonObject.get("sinceOntime" + index + "hour").getAsString();
final String rawType = jsonObject.get("type" + index + "hour").getAsString();
if (rawSinceOntime.isEmpty() && rawType.isEmpty()) {
return null;
}
return new Precipitation(parseFloat(rawSinceOntime), parseInt(rawType));
}
};
private static final AbstractExtractor<Sky> skiesExtractor = new AbstractExtractor<Sky>(compile("(?:code|name)(\\d)hour")) {
@Override
protected Sky parse(final int index, final JsonObject jsonObject) {
final String rawCode = jsonObject.get("code" + index + "hour").getAsString();
final String rawName = jsonObject.get("name" + index + "hour").getAsString();
if (rawCode.isEmpty() && rawName.isEmpty()) {
return null;
}
return new Sky(rawCode, rawName);
}
};
private static final AbstractExtractor<Float> temperaturesExtractor = new AbstractExtractor<Float>(compile("temp(\\d)hour")) {
@Override
protected Float parse(final int index, final JsonObject jsonObject) {
final String rawTemperature = jsonObject.get("temp" + index + "hour").getAsString();
if (rawTemperature.isEmpty()) {
return null;
}
return parseFloat(rawTemperature);
}
};
private static final AbstractExtractor<Float> humiditiesExtractor = new AbstractExtractor<Float>(compile("rh(\\d)hour")) {
@Override
protected Float parse(final int index, final JsonObject jsonObject) {
final String rawHumidity = jsonObject.get("rh" + index + "hour").getAsString();
if (rawHumidity.isEmpty()) {
return null;
}
return parseFloat(rawHumidity);
}
};
private abstract static class AbstractExtractor<T> {
private final Pattern pattern;
private AbstractExtractor(final Pattern pattern) {
this.pattern = pattern;
}
protected abstract T parse(int index, JsonObject jsonObject);
private List<T> parseList(final JsonObject jsonObject) {
final List<T> list = new ArrayList<>();
for (final Entry<String, JsonElement> e : jsonObject.entrySet()) {
final String key = e.getKey();
final Matcher matcher = pattern.matcher(key);
// Check if the given regular expression matches the key
if (matcher.matches()) {
// If yes, then just extract and parse the index
final int index = parseInt(matcher.group(1));
// And check if there is enough room in the result list because the JSON response may contain unordered keys
while (index > list.size()) {
list.add(null);
}
// As Java lists are 0-based
if (list.get(index - 1) == null) {
// Assuming that null marks an object that's probably not parsed yet
list.set(index - 1, parse(index, jsonObject));
}
}
}
return list;
}
}
}
現在，這一切可以放在一起：
public static void main(final String... args) {
final Gson gson = new GsonBuilder()
.setDateFormat("yyyy-MM-dd hh:mm:ss")
.registerTypeAdapter(Forecast.class, getForecastJsonDeserializer())
.create();
final Response response = gson.fromJson(JSON, Response.class);
System.out.println(response);
}
輸出：
響應{天氣預報=天氣{forecast3hours = [預測{格=電網{城市=」 충북'，county ='충주시'，village ='목행동'，緯度= 37.01356，經度= 127.90365}，timeRelease = Fri Feb 24 16:30:00 EET 2017，lightnings = [0，0，null，null] = [風{速度= 4.2，方向= 179.0}，風{速度= 3.1，方向= 176.0}，空，空]，沉澱= [沉澱ation {sinceOntime ='0.0'，type = 0}，降水{sinceOntime ='0.0'，type = 0}，null，null]，skies = [Sky {code ='SKY_V01'，name ='맑음'}，Sky {code ='SKY_V01'，name ='맑음'}，null，null]，溫度= [3.2,2.0，null，null]，溼度= [41.0,50.0，null，null]}]}，common = Common { alert = false，storm = false}，result = result {code = 9200，requestUrl ='/ weather/forecast/3hours？lon = 127.9259 & lat = 36.991 & version = 1 & appKey = 4ce0462a-3884-30ab-ab13-93efb1bc171f '，message ='성공'}}
@NizomjonHajiev沒問題，但還有一件事：我剛剛通過添加缺少的YnToBooleanJsonDeserializer實現（實際Y/N解析）我發佈原始答案時忘了提及，並將「country」更改爲「county」錯字。請參閱最新的答案。 –
我再有問題我怎麼能registerType適配器GSON匕首java.lang.IllegalArgumentException異常：無法創建類com.example.nizomjon.enjoyweather.model.test.Response –
提供 辛格爾頓 命名（生產） GSON轉換器provideGson（）{ return new GsonBuilder（） .setLenient（） .create（）; } 提供 辛格爾頓 命名（SKPLANET） GSON provideGsonSk（）{ 返回新GsonBuilder（） .setDateFormat（ 「YYYY-MM-DD HH：MM：SS」） .registerTypeAdapter（Forecast.class，ForecastJsonDeserializer .getForecastJsonDeserializer（）） .create（）; } –