yahoo的天气预报

 import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.HashMap;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

class GetWeatherInfo {
 public static HashMap<String, String> cityCode = new HashMap<String, String>();
 private final String[] dictionaryStrings = { "龙卷风", "热带风暴", "飓风", "强雷阵雨", "雷阵雨", "小雨加雪", "雨加冰雹", "雪加冰雹", "冰雨", "毛毛雨", "冻雨",
   "阵雨", "阵雨", "小雪", "零星小雪", "高吹雪", "雪", "冰雹", "雨夹雪", "尘", "雾", "薄雾", "多烟的", "大风", "有风", "寒冷", "阴天", "夜间阴天", "白天阴天",
   "夜间多云", "白天多云", "夜间清亮", "晴朗", "转晴", "转晴", "雨夹冰雹", "热", "雷阵雨", "雷阵雨", "雷阵雨", "雷阵雨", "大雪", "阵雪", "大雪", "多云", "雷", "阵雪",
   "雷雨" };

 public GetWeatherInfo() {
  initCitys();
 }

 /* 初始化城市代号 */
 private void initCitys() {
  cityCode.put("北京", "0008");
  cityCode.put("天津", "0133");
  cityCode.put("武汉", "0138");
  cityCode.put("杭州", "0044");
  cityCode.put("合肥 ", "0448");
  cityCode.put("上海 ", "0116");
  cityCode.put("福州 ", "0031");
  cityCode.put("重庆 ", "0017");
  cityCode.put("南昌 ", "0097");
  cityCode.put("香港 ", "0049");
  cityCode.put("济南 ", "0064");
  cityCode.put("澳门 ", "0512");
  cityCode.put("郑州 ", "0165");
  cityCode.put("呼和浩特 ", "0249");
  cityCode.put("乌鲁木齐 ", "0135");
  cityCode.put("长沙 ", "0013");
  cityCode.put("银川 ", "0259");
  cityCode.put("广州 ", "0037");
  cityCode.put("拉萨 ", "0080");
  cityCode.put("海口 ", "0502");
  cityCode.put("南京 ", "0100");
  cityCode.put("成都 ", "0016");
  cityCode.put("石家庄 ", "0122");
  cityCode.put("贵阳 ", "0039");
  cityCode.put("太原 ", "0129");
  cityCode.put("昆明 ", "0076");
  cityCode.put("沈阳 ", "0119");
  cityCode.put("西安 ", "0141");
  cityCode.put("长春 ", "0010");
  cityCode.put("兰州 ", "0079");
  cityCode.put("西宁 ", "0236");
 }

 private Document getWeatherXML(String cityCode) throws IOException {

//http://weather.yahooapis.com/forecastrss?w=2442047&u=c
  URL url = new URL("http://weather.yahooapis.com/forecastrss?w=" + cityCode + "&u=c");
  URLConnection connection = url.openConnection();
  Document Doc = stringToElement(connection.getInputStream());
  return Doc;
 }

 /* 保存获取的天气信息XML文档 */
 private void saveXML(Document Doc, String Path) {
  TransformerFactory transFactory = TransformerFactory.newInstance();
  Transformer transformer;
  try {
   transformer = transFactory.newTransformer();
   DOMSource domSource = new DOMSource(Doc);
   File file = new File(Path);
   FileOutputStream out = new FileOutputStream(file);
   StreamResult xmlResult = new StreamResult(out);
   transformer.transform(domSource, xmlResult);
  } catch (Exception e) {
   System.out.println("保存文件出错！");
  }
 }

 /* 获取天气信息 */
 public String getWeather(String city) {
  String result = null;
  try {
   Document doc = getWeatherXML(GetWeatherInfo.cityCode.get(city));
   NodeList nodeList = doc.getElementsByTagName("channel");
      for (int i = 0; i < nodeList.getLength(); i++) {
    Node node = nodeList.item(i);
    NodeList nodeList1 = node.getChildNodes();
    for (int j = 0; j < nodeList1.getLength(); j++) {
     Node node1 = nodeList1.item(j);
     if (node1.getNodeName().equalsIgnoreCase("item")) {
      NodeList nodeList2 = node1.getChildNodes();
      for (int k = 0; k < nodeList2.getLength(); k++) {
       Node node2 = nodeList2.item(k);
       if (node2.getNodeName().equalsIgnoreCase("yweather:forecast")) {
        NamedNodeMap nodeMap = node2.getAttributes();
        Node day =nodeMap.getNamedItem("day");
        Node lowNode = nodeMap.getNamedItem("low");
        Node highNode = nodeMap.getNamedItem("high");
        Node codeNode = nodeMap.getNamedItem("code");
        //String day = "今天";
        if (result == null) {
         result = "";
        } else {
         //day = " 明天";
        }
        result = result + day.getNodeValue() + " " + dictionaryStrings[Integer.parseInt(codeNode.getNodeValue())]
          + " 最低温度：" + lowNode.getNodeValue() + "℃ 最高温度：" + highNode.getNodeValue() + "℃ ";
       }
      }
     }
    }
   }
   saveXML(doc, "C:\Users\ygui\Desktop\Weather.xml");
  } catch (Exception e) {
   e.printStackTrace();
  }
  return result;
 }

 public Document stringToElement(InputStream input) {
  try {
   DocumentBuilder db = DocumentBuilderFactory.newInstance().newDocumentBuilder();
   Document doc = db.parse(input);
   return doc;
  } catch (Exception e) {
   return null;
  }
 }
}

public class Test {
 public static void main(String arg[]) {
  GetWeatherInfo info = new GetWeatherInfo();
  String weather = info.getWeather("武汉");
  System.out.println(weather);
 }
}