使用Yahoo Service实现天气预报
2008-01-05 10:18:13 来源:WEB开发网天气预告是非常有用的服务,假如能在网站上集成天气预告,能极大地方便用户查询。
寻遍了国内所有的气象站点,没找见提供Web服务的,太小气了,只能去国外找。NOAA(www.weather.gov)提供一个Web服务,但是死活连不上服务器,估计被屏蔽了,其他提供全球天气预告的有www.weather.com和yahoo,
不过weather.com的服务太麻烦,还需要注册,相比之下,yahoo的天气服务既简单又快速,只需一个http请求,然后解析返回的xml即可获得天气预告。
以北京为例,在weather.yahoo.com查找北京的城市代码为CHXX0008,对应的URL为:
http://xml.weather.yahoo.com/forecastrss?u=c&p=CHXX0008
然后,通过SAX解析返回的XML:
URL url = new URL("http://xml.weather.yahoo.com/forecastrss?u=c&p=CHXX0008");
InputStream input = url.openStream();
SAXParserFactory factory = SAXParserFactory.newInstance();
factory.setNamespaceAware(false);
SAXParser parser = factory.newSAXParser();
parser.parse(input, new YahooHandler());
自己定义一个YahooHandler来响应SAX事件:
/**
* For more information, please visit: http://www.crackj2ee.com
* Author: Liao Xuefeng
*/
public class YahooHandler extends DefaultHandler {
public void startElement(String uri, String localName, String qName, Attributes attributes)
throws SAXException {
if("yweather:condition".equals(qName)) {
String s_date = attributes.getValue(3);
try {
Date publish = new SimpleDateFormat("EEE, dd MMM yyyy hh:mm a z",
Locale.US).parse(s_date);
//System.out.PRintln("Publish: " + publish.toString());
}
catch (Exception e) {
e.printStackTrace();
throw new SAXException("Cannot parse date: " + s_date);
}
}
else if("yweather:forecast".equals(qName)) {
String s_date = attributes.getValue(1);
Date date = null;
try {
date = new SimpleDateFormat("dd MMM yyyy", Locale.US).parse(s_date);
}
catch (Exception e) {
e.printStackTrace();
throw new SAXException("Cannot parse date: " + s_date);
}
int low = Integer.parseInt(attributes.getValue(2));
int high = Integer.parseInt(attributes.getValue(3));
String text = attributes.getValue(4);
int code = Integer.parseInt(attributes.getValue(5));
System.out.println("Weather: "+ text + ", low=" + low + ", high=" + high);
}
super.startElement(uri, localName, qName, attributes);
}
}
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