从WeatherUnderground读取JSON回复 [英] Reading a JSON reply from WeatherUnderground
本文介绍了从WeatherUnderground读取JSON回复的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
package test;
导入java.net。*;
import java.io. *;
import com.google.gson。*;
import com.google.gson.stream.JsonReader;
public class TestGson {
URL callToApi;
// -------------------------------------------- ----------------------------------
public static void main（String [] args）{
new TestGson（）;
}
// --------------------------------------- ---------------------------------------
public TestGson（）{
尝试{
sendCallToApi（）;
readJson（）;
} catch（IOException e）{
e.printStackTrace（）;
}
}
// ---------------------------------- --------------------------------------------
public void sendCallToApi（）{
try {
callToApi = new URL（http://api.wunderground.com/api+
/ [insert key here]+
/ geolookup / conditions / forecast / q /+
Australia /+
Sydney.json）;
} catch（MalformedURLException e）{
e.printStackTrace（）;
}
}
// ---------------------------------- --------------------------------------------
public void readJson（）抛出IOException {
Gson g = new Gson（）;
InputStreamReader in = new InputStreamReader（callToApi.openStream（））;
BufferedReader reader = new BufferedReader（in）;
String message =hello;
StringBuffer buf = new StringBuffer（）;
while（message！= null）{
message = reader.readLine（）;
buf.append（message）;
}
message = buf.toString（）;
String wdf = g.fromJson（message，String.class）;
System.out.println（wdf）;
}
// --------------------------------------- ---------------------------------------
}
这是我第一次尝试使用GSON解析JSON。我只是打电话给Weather Underground网站，要求他们寄给我澳大利亚悉尼的天气。
但是，我得到了多个错误：
线程main中的异常com.google.gson.JsonSyntaxException：java.lang.IllegalStateException：期望一个字符串，但是在第1行的BEGIN_OBJECT第2列
在com.google .gson.Gson.fromJson（Gson.java:806）
在com.google.gson.Gson.fromJson（Gson.java:761）
在com.google.gson.Gson.fromJson（Gson .java：710）
at com.google.gson.Gson.fromJson（Gson.java:682）
at test.TestGson.readJson（TestGson.java:49）
at test。 TestGson。< init>（TestGson.java:19）
at test.TestGson.main（TestGson.java:13）
引起：java.lang.IllegalStateException：期望一个字符串，但是BEGIN_OBJECT在第1行第2列
位于com.google.gson.stream.JsonReader.nextString（JsonReader.java:464）
位于com.google.gson.internal.bind.TypeAdapters $ 13.read（TypeAdapters.java ：349）
在com.google.gson.internal.bind.TypeAdapters $ 13.read（TypeAdapters.java:337）
在com.google.gson.Gson.fromJson（Gson.java:795）
。 .. 6更多
什么导致了这些错误？我如何正确地呼叫Weather Underground API以接收天气信息？
我通过修改Mykong.com上给出的示例尝试了此操作。
JSON地下天气的回复
{response：{ 版本：0.1，服务条款：http://www.wunderground.com/weather/api/d/terms.html，功能：{geolookup：1，条件：1 ，位置：{type：INTLCITY，country：SD，country_iso3166：SA，country_name：沙特阿拉伯，州 ：，city：Jeddah，tz_short：AST，tz_long：亚洲/利雅得，lat：21.67000008，lon：39.15000153，zip： 00000，magic：1，wmo：41024，l：/ q / zmw：00000.1.41024，requesturl：global / stations / 41024.html wuiurl：http://www.wunderground.com/global/stations/41024.html，nearby_weather_stations：{airport：{station：[{city：吉达国王阿卜杜勒阿齐兹国际机场，国家：，国家：沙特阿拉伯，icao：O EJN，lat：21.70000076，lon：39.18333435}，{city：Jeddah，state：，country：SD，icao：OEJN lat：21.67000008，lon：39.15000153}，{city：Makkah，state：，country：SD，icao ，lat：21.43000031，lon：39.77000046}]}，pws：{station：[]}}}，current_observation：{image：{url： http://icons-ak.wxug.com/graphics/wu2/logo_130x80.png，title：Weather Underground，link：http://www.wunderground.com}，display_location ：沙特阿拉伯，沙特阿拉伯，城市 SA，zip：00000，纬度：21.67000008，经度：39.15000153，海拔：12.00000000}，observation_location：{full：Jeddah 城市：吉达，国家：，国家：SD， country_iso3166：SA，纬度：21.67000008，经度：39.15000153，高程：39英尺}，估计：{}，station_id：OEJN观察时间：最后更新时间为2月12日上午9:00 AST，observation_time_rfc822：星期二，2013年2月12日09:00:00 +0300，observation_epoch：1360648800，local_time_rfc822：星期二，2013年2月12日09时08分53秒+0300，local_epoch：1360649333，local_tz_short：AST，local_tz_long：Asia / Riyadh，local_tz_offset：+ 0300 ：Clear，temperature_string：77F（25C），temp_f：77，temp_c：25，ative_humidity：57％，wind_string： MPH，wind_dir，North，wind_degrees10，wind_mph10，wind_gust_mph0，wind_kph17，wind_gust_kph0，pressure_mb，1011 pressure_in：29.86，pressure_trend：0，露点_字符串：61F（16C），露点t_f：61，dewpoint_c：16，heat_index_string：NA，heat_index_f：NA，heat_index_c：NA，windchill_string：NA，windchill_f ，windchill_c：NA，feellike_string：77F（25C），feellike_f：77，feellike_c：25，visibility_mi：N / A，visibility_km ：N / A，solarradiation：，UV： - 1，precipitation_1hr_string： - 9999.00 in（-9999.00mm），precip_1hr_in： - 9999.00，precip_1hr_metric ： - 9999.00，precipitation_today_string：0.00 in（0.0 mm），precip_today_in：0.00，precipitation_today_metric：0.0，icon：clear，icon_url：http ：//icons-ak.wxug.com/i/c/k/clear.gif，forecast_url：http://www.wunderground.com/global/stations/41024.html，history_url： http://www.wunderground.com/history/airport/OEJN/2013/2/12/DailyHistory.html，ob_url：http://www.wunderground.com/cgi-bin/findweather/getForecast ？查询= 21.67000008,39.15000153\" }，forecast：{txt_forecast：{date：3:00 AM AST，forecastday：[{period：0，icon：partiallycloudy，icon_url：http ：//icons-ak.wxug.com/i/c/k/partlycloudy.gif，标题：星期二，fcttext：清晨，晴间多云。 84F高。凉风习习。 北风从10至20英里/小时。，fcttext_metric：早上晴，一会儿晴间多云。高29C。凉风习习。风速从15至30公里/小时。，pop：0}，{period：1，icon：clear，icon_url：http：// icons-ak .wxug.com / i / c / k / clear.gif，标题：星期二晚上，fcttext：清除。 70F的低。以10-15英里/小时的速度从北大西洋风吹过。，fcttext_metric：清除。低于21C。凉风习习。风速从15至25公里/小时。，pop：0}，{period：2，icon：partiallycloudy，icon_url：http：// icons-ak .wxug.com / i / c / k / partiallycloudy.gif，title：星期三，fcttext：早上晴朗，然后局部多云。 88F高。风力从北方风力的5到15英里/小时。，fcttext_metric：晴朗，早上晴间多云。 31C高。凉风习习。风速从10到25 km / h。，pop：0}，{period：3，icon：clear，icon_url：http：// icons-ak .wxug.com / i / c / k / clear.gif，标题：周三晚上，fcttext：晚上晴朗，然后局部多云。 70F的低。西北风力5至15英里/小时。，fcttext_metric：晴朗，傍晚时分偏多云。低于21C。凉风习习。风速从10到25公里/小时。，pop：0}，{period：4，icon：partlycloudy，icon_url：http：// icons-ak .wxug.com / i / c / k / partiallycloudy.gif，标题：星期四，fcttext：清晨，晴间多云。 88F高。风速从北方以5至10英里/小时的速度在下午转移至WSW。，fcttext_metric：清晨，晴间多云。 31C高。 ，pop：0}，{period：5，icon：清除，icon_url：从北方向以5至15公里/小时的速度向下移动至WSW。 http://icons-ak.wxug.com/i/c/k/clear.gif，title：星期四之夜，fcttext：清晰。 73F的低。风力从WNW上5到10英里/小时。，fcttext_metric：清除。低23C。 WNW以5至15公里/小时的风速，pop：0}，{period：6，icon：clear，icon_url：http：// icons-ak .wxug.com / i / c / k / clear.gif，title：星期五，fcttext：清除。 88F高。 NNE以5至10英里/小时的速度在下午转移到WSW。，fcttext_metric：晴。 31C高。 NNE以5至20公里/小时的速度在下午转移至WSW。，pop：0}，{period：7，icon：clear，icon_url： http://icons-ak.wxug.com/i/c/k/clear.gif，title：星期五之夜，fcttext：清除。低于72F。风速从5到10英里/小时。，fcttext_metric：清除。低于22C。风速从5到15公里/小时。，pop：0}]}，simpleforecast：{forecastday：[{date：{epoch：1360692000，漂亮：2013年2月12日9:00 AST，日：12，月：2，年：2013年，yday：42，小时：21，min： 00，sec：0，isdst：0，monthname：2月，weekday_short：Tue，weekday：Tuesday，ampm：PM， tz_short：AST，tz_long：Asia / Riyadh，period：1，high：{fahrenheit：84，celsius：29}， ：{fahrenheit：70，celsius：21}，conditions：部分多云，icon：partiallycloudy，icon_url：http：//icons-ak.wxug .com / i / c / k / partiallycloudy.gif，skyicon：mostlysunny，pop：0，qpf_allday：{in：0.00，mm：0.0}，qpf_day： {in：0.00，mm：0.0}，qpf_night：{in：0.00，mm：0.0}，snow_allday：{in 0，cm：0}，snow_day：{in：0，cm：0}，snow_night：{in：0，cm：0}，maxwind mph：17，kph：27，dir：NW，度：317}，avewind：{mph：14，kph：22，dir ，度数：324}，平衡度：52，最大湿度：74，最小湿度：43}，{日期：{epoch：1360778400，漂亮 2013年2月13日的PM AST，日：13，月：2，年：2013，yday：43，小时：21，min：00 ：0，月，月，月，星期 ，tz_long：Asia / Riyadh}，period：2，high：{fahrenheit：88，celsius：31}，low：{fahrenheit 70，摄氏，21，条件：部分多云，图标：partiallycloudy，icon_url：http：// icons- ak.wxug.com/i/c/k/partlycloudy.gif，skyicon：partiallycloudy，pop：0，qpf_allday：{in：0.00，mm：0.0}， qpf_day：{in：0.00，mm：0.0}，qpf_night：{in：0.00，mm：0.0}，snow_allday：{in：0，cm 0}snow_day：{in：0，cm：0}，snow_night：{in：0，cm：0}，maxwind：{mph kph：22，dir：NW，度：308}，avewind：{mph：12，kph：19，dir：NW，度 315，avehumidity：51，maxhumidity：75，minhumidity：39}，{date：{epoch：1360864800，pretty 2013，yday：44，hour：21，min：00，sec：0，isdst ：0，monthname：2月，weekday_short：星期四，星期几：星期四，ampm：P M，tz_short：AST，tz_long：Asia / Riyadh}，period：3，high：{fahrenheit：88，celsius：31 low：{fahrenheit：73，celsius：23}，conditions：Partly Cloudy，icon：partiallycloudy，icon_url：http：// icons- ak.wxug.com/i/c/k/partlycloudy.gif，skyicon：mostlysunny，pop：0，qpf_allday：{in：0.00，mm：0.0}， qpf_day：{in：0.00，mm：0.0}，qpf_night：{in：0.00，mm：0.0}，snow_allday：{in：0，cm 0}snow_day：{in：0，cm：0}，snow_night：{in：0，cm：0}，maxwind：{mph kph：14，dir：West，度：259}，avewind：{mph：7，kph：11，dir：WSW，度 250}，avehumidity：51，maxhumidity：69，minhumid ity：37，{date：{epoch：1360951200，pretty：9:00 PM 2013年2月15日AST，day：15，month：2， yday：45，hour：21，min：00，sec：0，isdst：0，monthname：February，weekday_short ：星期五，星期几，星期五，安眠，PM，tz_short：AST，tz_long：亚洲/利雅得}，时间段：4， {fahrenheit：88，celsius：31}，low：{fahrenheit：72，celsius：22}，conditions：Clear， ：clear，icon_url：http://icons-ak.wxug.com/i/c/k/clear.gif，skyicon：mostlysunny，pop：0，qpf_allday ：{in：0.00，mm：0.0}，qpf_day：{in：0.00，mm：0.0}，qpf_night：{in：0.00，mm }，snow_allday：{in：0，cm：0}，snow_day：{in：0，cm：0}，snow_night：{in：0，厘米： 0}，maxwind：{mph：10，kph：16，dir：WSW，度：248}，avewind：{mph：7，kph 11，dir：WSW，度：248}，avehumidity：53，maxhumidity：60，minhumidity：38}]}}} null
解决方案
This is my first attempt at parsing JSON using GSON. I am simply making a call to the Weather Underground site asking them to send me the weather of Sydney, Australia.
However, I get multiple errors:
您似乎不明白 Gson 确实。这是一个JSON解析器，特别是将JSON反序列化为Java POJO的解析器。
在你的代码中有：
字符串wdf = g。 fromJson（message，String.class）;
您告诉Gson将JSON反序列化为Java 您需要创建一个POJO，以便JSON可以反序列化，或者使用Gson的解析器和关联的对象/方法从您想要的JSON中选择部分。 以下是POJO看起来的样子（所有公开的没有getter / setter的字段只是为了让这个例子变小）： 然后，您可以将JSON反序列化为 如果你不想去POJO路线，你可以解析JSON然后得到你想要的从它： 现在您可以使用 GSON用户指南编写得很好，并对此进行了详细解释。 / p> 编辑以添加：您的JSON结尾处的 您追加 String 对象。它不能那样做;你的JSON 不是一个 String 对象 - 它是从Weather Underground返回的一个很大的JSON对象。您已经拥有包含JSON文本本身的Java String （ message ）。
class MyWUPojo {
public response response;
//在此之后匹配JSON
}
class响应{
public String version;
public String termsofservice;
public Map< String，Integer>特征;
}
MyWUPojo with：
MyWUPojo wup = new Gson（）。fromJson（message，MyWUPojo.class ）;
JsonObject o =（JsonObject）new JsonParser（）。parse（message）;
JsonObject 来访问解析的JSON。 （请参阅： http：// google-gson.googlecode.com/svn/trunk/gson/docs/javadocs/com/google/gson/JsonObject.html ）
null 是由此导致的：
while（message！= null）{
message = reader.readLine（）;
buf.append（message）;
}
null 然后
$ b
while（（message = reader.readline（））！= null）{
buf .append（消息）;
}
package test;
import java.net.*;
import java.io.*;
import com.google.gson.*;
import com.google.gson.stream.JsonReader;
public class TestGson {
URL callToApi;
//------------------------------------------------------------------------------
public static void main(String[] args) {
new TestGson();
}
//------------------------------------------------------------------------------
public TestGson(){
try{
sendCallToApi();
readJson();
}catch(IOException e){
e.printStackTrace();
}
}
//------------------------------------------------------------------------------
public void sendCallToApi(){
try{
callToApi = new URL("http://api.wunderground.com/api" +
"/[insert key here]" +
"/geolookup/conditions/forecast/q/" +
"Australia/" +
"Sydney.json");
}catch(MalformedURLException e){
e.printStackTrace();
}
}
//------------------------------------------------------------------------------
public void readJson() throws IOException{
Gson g = new Gson();
InputStreamReader in = new InputStreamReader(callToApi.openStream());
BufferedReader reader = new BufferedReader(in);
String message = "hello";
StringBuffer buf = new StringBuffer();
while(message!=null){
message = reader.readLine();
buf.append(message);
}
message = buf.toString();
String wdf = g.fromJson(message, String.class);
System.out.println(wdf);
}
//------------------------------------------------------------------------------
}
This is my first attempt at parsing JSON using GSON. I am simply making a call to the Weather Underground site asking them to send me the weather of Sydney, Australia.
However, I get multiple errors:
Exception in thread "main" com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected a string but was BEGIN_OBJECT at line 1 column 2
at com.google.gson.Gson.fromJson(Gson.java:806)
at com.google.gson.Gson.fromJson(Gson.java:761)
at com.google.gson.Gson.fromJson(Gson.java:710)
at com.google.gson.Gson.fromJson(Gson.java:682)
at test.TestGson.readJson(TestGson.java:49)
at test.TestGson.<init>(TestGson.java:19)
at test.TestGson.main(TestGson.java:13)
Caused by: java.lang.IllegalStateException: Expected a string but was BEGIN_OBJECT at line 1 column 2
at com.google.gson.stream.JsonReader.nextString(JsonReader.java:464)
at com.google.gson.internal.bind.TypeAdapters$13.read(TypeAdapters.java:349)
at com.google.gson.internal.bind.TypeAdapters$13.read(TypeAdapters.java:337)
at com.google.gson.Gson.fromJson(Gson.java:795)
... 6 more
What is causing those errors? How do I properly make the call to the Weather Underground API to receive the weather info?
I tried this by modifying the example given on Mykong.com.
JSON Reply from Weather Underground
{ "response": { "version": "0.1" ,"termsofService": "http://www.wunderground.com/weather/api/d/terms.html" ,"features": { "geolookup": 1 , "conditions": 1 , "forecast": 1 } } , "location": { "type":"INTLCITY", "country":"SD", "country_iso3166":"SA", "country_name":"Saudi Arabia", "state":"", "city":"Jeddah", "tz_short":"AST", "tz_long":"Asia/Riyadh", "lat":"21.67000008", "lon":"39.15000153", "zip":"00000", "magic":"1", "wmo":"41024", "l":"/q/zmw:00000.1.41024", "requesturl":"global/stations/41024.html", "wuiurl":"http://www.wunderground.com/global/stations/41024.html", "nearby_weather_stations": { "airport": { "station": [ { "city":"Jeddah King Abdul Aziz International Airport", "state":"", "country":"Saudi Arabia", "icao":"OEJN", "lat":"21.70000076", "lon":"39.18333435" }, { "city":"Jeddah", "state":"", "country":"SD", "icao":"OEJN", "lat":"21.67000008", "lon":"39.15000153" }, { "city":"Makkah", "state":"", "country":"SD", "icao":"OEMK", "lat":"21.43000031", "lon":"39.77000046" } ] } , "pws": { "station": [ ] } } } , "current_observation": { "image": { "url":"http://icons-ak.wxug.com/graphics/wu2/logo_130x80.png", "title":"Weather Underground", "link":"http://www.wunderground.com" }, "display_location": { "full":"Jeddah, Saudi Arabia", "city":"Jeddah", "state":"", "state_name":"Saudi Arabia", "country":"SD", "country_iso3166":"SA", "zip":"00000", "latitude":"21.67000008", "longitude":"39.15000153", "elevation":"12.00000000" }, "observation_location": { "full":"Jeddah, ", "city":"Jeddah", "state":"", "country":"SD", "country_iso3166":"SA", "latitude":"21.67000008", "longitude":"39.15000153", "elevation":"39 ft" }, "estimated": { }, "station_id":"OEJN", "observation_time":"Last Updated on February 12, 9:00 AM AST", "observation_time_rfc822":"Tue, 12 Feb 2013 09:00:00 +0300", "observation_epoch":"1360648800", "local_time_rfc822":"Tue, 12 Feb 2013 09:08:53 +0300", "local_epoch":"1360649333", "local_tz_short":"AST", "local_tz_long":"Asia/Riyadh", "local_tz_offset":"+0300", "weather":"Clear", "temperature_string":"77 F (25 C)", "temp_f":77, "temp_c":25, "relative_humidity":"57%", "wind_string":"From the North at 10 MPH", "wind_dir":"North", "wind_degrees":10, "wind_mph":10, "wind_gust_mph":0, "wind_kph":17, "wind_gust_kph":0, "pressure_mb":"1011", "pressure_in":"29.86", "pressure_trend":"0", "dewpoint_string":"61 F (16 C)", "dewpoint_f":61, "dewpoint_c":16, "heat_index_string":"NA", "heat_index_f":"NA", "heat_index_c":"NA", "windchill_string":"NA", "windchill_f":"NA", "windchill_c":"NA", "feelslike_string":"77 F (25 C)", "feelslike_f":"77", "feelslike_c":"25", "visibility_mi":"N/A", "visibility_km":"N/A", "solarradiation":"", "UV":"-1", "precip_1hr_string":"-9999.00 in (-9999.00 mm)", "precip_1hr_in":"-9999.00", "precip_1hr_metric":"-9999.00", "precip_today_string":"0.00 in (0.0 mm)", "precip_today_in":"0.00", "precip_today_metric":"0.0", "icon":"clear", "icon_url":"http://icons-ak.wxug.com/i/c/k/clear.gif", "forecast_url":"http://www.wunderground.com/global/stations/41024.html", "history_url":"http://www.wunderground.com/history/airport/OEJN/2013/2/12/DailyHistory.html", "ob_url":"http://www.wunderground.com/cgi-bin/findweather/getForecast?query=21.67000008,39.15000153" } , "forecast":{ "txt_forecast": { "date":"3:00 AM AST", "forecastday": [ { "period":0, "icon":"partlycloudy", "icon_url":"http://icons-ak.wxug.com/i/c/k/partlycloudy.gif", "title":"Tuesday", "fcttext":"Clear in the morning, then partly cloudy. High of 84F. Breezy. Winds from the NNW at 10 to 20 mph.", "fcttext_metric":"Clear in the morning, then partly cloudy. High of 29C. Breezy. Winds from the NNW at 15 to 30 km/h.", "pop":"0" } , { "period":1, "icon":"clear", "icon_url":"http://icons-ak.wxug.com/i/c/k/clear.gif", "title":"Tuesday Night", "fcttext":"Clear. Low of 70F. Winds from the NNW at 10 to 15 mph.", "fcttext_metric":"Clear. Low of 21C. Breezy. Winds from the NNW at 15 to 25 km/h.", "pop":"0" } , { "period":2, "icon":"partlycloudy", "icon_url":"http://icons-ak.wxug.com/i/c/k/partlycloudy.gif", "title":"Wednesday", "fcttext":"Clear in the morning, then partly cloudy. High of 88F. Winds from the NNW at 5 to 15 mph.", "fcttext_metric":"Clear in the morning, then partly cloudy. High of 31C. Breezy. Winds from the NNW at 10 to 25 km/h.", "pop":"0" } , { "period":3, "icon":"clear", "icon_url":"http://icons-ak.wxug.com/i/c/k/clear.gif", "title":"Wednesday Night", "fcttext":"Clear in the evening, then partly cloudy. Low of 70F. Winds from the NW at 5 to 15 mph.", "fcttext_metric":"Clear in the evening, then partly cloudy. Low of 21C. Breezy. Winds from the NW at 10 to 25 km/h.", "pop":"0" } , { "period":4, "icon":"partlycloudy", "icon_url":"http://icons-ak.wxug.com/i/c/k/partlycloudy.gif", "title":"Thursday", "fcttext":"Clear in the morning, then partly cloudy. High of 88F. Winds from the North at 5 to 10 mph shifting to the WSW in the afternoon.", "fcttext_metric":"Clear in the morning, then partly cloudy. High of 31C. Winds from the North at 5 to 15 km/h shifting to the WSW in the afternoon.", "pop":"0" } , { "period":5, "icon":"clear", "icon_url":"http://icons-ak.wxug.com/i/c/k/clear.gif", "title":"Thursday Night", "fcttext":"Clear. Low of 73F. Winds from the WNW at 5 to 10 mph.", "fcttext_metric":"Clear. Low of 23C. Winds from the WNW at 5 to 15 km/h.", "pop":"0" } , { "period":6, "icon":"clear", "icon_url":"http://icons-ak.wxug.com/i/c/k/clear.gif", "title":"Friday", "fcttext":"Clear. High of 88F. Winds from the NNE at 5 to 10 mph shifting to the WSW in the afternoon.", "fcttext_metric":"Clear. High of 31C. Winds from the NNE at 5 to 20 km/h shifting to the WSW in the afternoon.", "pop":"0" } , { "period":7, "icon":"clear", "icon_url":"http://icons-ak.wxug.com/i/c/k/clear.gif", "title":"Friday Night", "fcttext":"Clear. Low of 72F. Winds from the NW at 5 to 10 mph.", "fcttext_metric":"Clear. Low of 22C. Winds from the NW at 5 to 15 km/h.", "pop":"0" } ] }, "simpleforecast": { "forecastday": [ {"date":{ "epoch":"1360692000", "pretty":"9:00 PM AST on February 12, 2013", "day":12, "month":2, "year":2013, "yday":42, "hour":21, "min":"00", "sec":0, "isdst":"0", "monthname":"February", "weekday_short":"Tue", "weekday":"Tuesday", "ampm":"PM", "tz_short":"AST", "tz_long":"Asia/Riyadh"}, "period":1, "high": { "fahrenheit":"84", "celsius":"29" }, "low": { "fahrenheit":"70", "celsius":"21" }, "conditions":"Partly Cloudy", "icon":"partlycloudy", "icon_url":"http://icons-ak.wxug.com/i/c/k/partlycloudy.gif", "skyicon":"mostlysunny", "pop":0, "qpf_allday": { "in": 0.00, "mm": 0.0 }, "qpf_day": { "in": 0.00, "mm": 0.0 }, "qpf_night": { "in": 0.00, "mm": 0.0 }, "snow_allday": { "in": 0, "cm": 0 }, "snow_day": { "in": 0, "cm": 0 }, "snow_night": { "in": 0, "cm": 0 }, "maxwind": { "mph": 17, "kph": 27, "dir": "NW", "degrees": 317 }, "avewind": { "mph": 14, "kph": 22, "dir": "NW", "degrees": 324 }, "avehumidity": 52, "maxhumidity": 74, "minhumidity": 43 } , {"date":{ "epoch":"1360778400", "pretty":"9:00 PM AST on February 13, 2013", "day":13, "month":2, "year":2013, "yday":43, "hour":21, "min":"00", "sec":0, "isdst":"0", "monthname":"February", "weekday_short":"Wed", "weekday":"Wednesday", "ampm":"PM", "tz_short":"AST", "tz_long":"Asia/Riyadh"}, "period":2, "high": { "fahrenheit":"88", "celsius":"31" }, "low": { "fahrenheit":"70", "celsius":"21" }, "conditions":"Partly Cloudy", "icon":"partlycloudy", "icon_url":"http://icons-ak.wxug.com/i/c/k/partlycloudy.gif", "skyicon":"partlycloudy", "pop":0, "qpf_allday": { "in": 0.00, "mm": 0.0 }, "qpf_day": { "in": 0.00, "mm": 0.0 }, "qpf_night": { "in": 0.00, "mm": 0.0 }, "snow_allday": { "in": 0, "cm": 0 }, "snow_day": { "in": 0, "cm": 0 }, "snow_night": { "in": 0, "cm": 0 }, "maxwind": { "mph": 14, "kph": 22, "dir": "NW", "degrees": 308 }, "avewind": { "mph": 12, "kph": 19, "dir": "NW", "degrees": 315 }, "avehumidity": 51, "maxhumidity": 75, "minhumidity": 39 } , {"date":{ "epoch":"1360864800", "pretty":"9:00 PM AST on February 14, 2013", "day":14, "month":2, "year":2013, "yday":44, "hour":21, "min":"00", "sec":0, "isdst":"0", "monthname":"February", "weekday_short":"Thu", "weekday":"Thursday", "ampm":"PM", "tz_short":"AST", "tz_long":"Asia/Riyadh"}, "period":3, "high": { "fahrenheit":"88", "celsius":"31" }, "low": { "fahrenheit":"73", "celsius":"23" }, "conditions":"Partly Cloudy", "icon":"partlycloudy", "icon_url":"http://icons-ak.wxug.com/i/c/k/partlycloudy.gif", "skyicon":"mostlysunny", "pop":0, "qpf_allday": { "in": 0.00, "mm": 0.0 }, "qpf_day": { "in": 0.00, "mm": 0.0 }, "qpf_night": { "in": 0.00, "mm": 0.0 }, "snow_allday": { "in": 0, "cm": 0 }, "snow_day": { "in": 0, "cm": 0 }, "snow_night": { "in": 0, "cm": 0 }, "maxwind": { "mph": 9, "kph": 14, "dir": "West", "degrees": 259 }, "avewind": { "mph": 7, "kph": 11, "dir": "WSW", "degrees": 250 }, "avehumidity": 51, "maxhumidity": 69, "minhumidity": 37 } , {"date":{ "epoch":"1360951200", "pretty":"9:00 PM AST on February 15, 2013", "day":15, "month":2, "year":2013, "yday":45, "hour":21, "min":"00", "sec":0, "isdst":"0", "monthname":"February", "weekday_short":"Fri", "weekday":"Friday", "ampm":"PM", "tz_short":"AST", "tz_long":"Asia/Riyadh"}, "period":4, "high": { "fahrenheit":"88", "celsius":"31" }, "low": { "fahrenheit":"72", "celsius":"22" }, "conditions":"Clear", "icon":"clear", "icon_url":"http://icons-ak.wxug.com/i/c/k/clear.gif", "skyicon":"mostlysunny", "pop":0, "qpf_allday": { "in": 0.00, "mm": 0.0 }, "qpf_day": { "in": 0.00, "mm": 0.0 }, "qpf_night": { "in": 0.00, "mm": 0.0 }, "snow_allday": { "in": 0, "cm": 0 }, "snow_day": { "in": 0, "cm": 0 }, "snow_night": { "in": 0, "cm": 0 }, "maxwind": { "mph": 10, "kph": 16, "dir": "WSW", "degrees": 248 }, "avewind": { "mph": 7, "kph": 11, "dir": "WSW", "degrees": 248 }, "avehumidity": 53, "maxhumidity": 60, "minhumidity": 38 } ] } }}null
解决方案
You don't seem to understand what Gson does. It's a JSON parser, specifically one that will deserialize JSON to a Java POJO.
In your code you have:
String wdf = g.fromJson(message, String.class);
You're telling Gson to deserialize the JSON to a Java String object. It can't do that; your JSON isn't a String object - it's a big JSON object returned from Weather Underground. You already have a Java String (message) that contains the JSON text itself.
You either need to create a POJO that the JSON can be deserialized to, or pick the parts out of the JSON you want using Gson's parser and associated objects/methods.
Here's the start of what a POJO would look like (all fields public with no getters/setters just to make this example small):
class MyWUPojo {
public Response response;
// more after this that match the JSON
}
class Response {
public String version;
public String termsofservice;
public Map<String, Integer> features;
}
You'd then deserialize the JSON into an instance of MyWUPojo with:
MyWUPojo wup = new Gson().fromJson(message,MyWUPojo.class);
If you didn't want to go the POJO route you could parse the JSON then get what you want from it:
JsonObject o = (JsonObject) new JsonParser().parse(message);
Now you' can use the various methods of JsonObject to access the parsed JSON. (See: http://google-gson.googlecode.com/svn/trunk/gson/docs/javadocs/com/google/gson/JsonObject.html )
The GSON User's Guide is pretty well written and explains this and more in great detail.
Edit to add: That null at the end of your JSON is caused by this:
while(message!=null){
message = reader.readLine();
buf.append(message);
}
You append null then the loop exits. It needs to be:
while ((message = reader.readline()) != null) {
buf.append(message);
}
这篇关于从WeatherUnderground读取JSON回复的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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