编辑:2020 年更新 - 请忽略以下问题,因为 Google 的天气 API 不再可用。如果您对使用天气 API 感兴趣,Darksky 是大多数人使用的事实:https://darksky.net/dev
如果您使用 Java,解析 JSON 的正常方法是使用 org.json: https://devqa.io/java/how-to-parse-json-in-java
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原始问题如下。
<小时/>我最近一直在研究 xml 文档和 java,但我在使用 google 天气 API 方面却完全没有运气。
假设我正在尝试做一个简单的对象来存储当前温度,并预测明天的温度,我该怎么做?
http://www.google.com/ig/api?weather=02110这是我家乡的工作示例。
谢谢
使用此代码:
public static final String[] xmlLoader(){
String xmlData[] = new String[2];
try {
URL googleWeatherXml = new URL("http://www.google.com/ig/api?weather=02110");
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(googleWeatherXml.openStream());
// normalize text representation
doc.getDocumentElement ().normalize ();
NodeList listOfWeek = doc.getElementsByTagName("");
Node firstWeekNode = listOfWeek.item(dateCounter-1);
int totalWeeks = listOfWeek.getLength();
//Break xml file into parts, then break those parts down int an array by passing individual elements to srtings
if(firstWeekNode.getNodeType() == Node.ELEMENT_NODE){
Element firstWeekElement = (Element)firstWeekNode;
//-------
NodeList dateList = firstWeekElement.getElementsByTagName("date");
Element dateElement = (Element)dateList.item(0);
NodeList textDateList = dateElement.getChildNodes();
xmlData[0]= (((Node)textDateList.item(0)).getNodeValue().trim()).toString();
//-------
NodeList riddleList = firstWeekElement.getElementsByTagName("riddle");
Element riddleElement = (Element)riddleList.item(0);
NodeList textRiddleList = riddleElement.getChildNodes();
xmlData[1]= (((Node)textRiddleList.item(0)).getNodeValue().trim()).toString();
//----
NodeList lWSList = firstWeekElement.getElementsByTagName("lastWeekSolution");
Element ageElement = (Element)lWSList.item(0);
NodeList textLWSList = ageElement.getChildNodes();
xmlData[2]= (((Node)textLWSList.item(0)).getNodeValue().trim()).toString();
//------
}//end of if clause
}
catch(MalformedURLException f){System.err.println(f.getMessage()); }
catch(NullPointerException npe){
System.out.println("The Weather Data you searched for is incorrect or does not yet exist, try again. ");
String s[] = {" ", " "};
main(s);
}
catch (SAXParseException err) {
System.out.println ("** Parsing error" + ", line "
+ err.getLineNumber () + ", uri " + err.getSystemId ());
System.out.println(" " + err.getMessage ());
}
catch (SAXException e) {
Exception x = e.getException ();
((x == null) ? e : x).printStackTrace ();
}catch (Throwable t) {
t.printStackTrace ();
}
return xmlData;
}
无论我做什么,都会得到大量的空指针。
最佳答案
当您调用 .getElementsByTagName() 时,您需要对返回的值进行保护:
NodeList dateList = firstWeekElement.getElementsByTagName("date");
if (datelist != null) {
Element dateElement = (Element)dateList.item(0);
等等。
更新
现在我查看 XML,发现没有
NodeList forecasts = firstWeekElement.getElementsByTagName("forecast_information");
if (forecasts != null) {
Element forecastElement = (Element)forecasts.item(0);
关于java - 使用 Java 从 google Weather API 中提取数据,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/10487508/