Android開發：天氣預報Dom解析

DOM是用與平台無關和語言無關的方式表示XML文檔的官方W3C標准，DOM是以層次結構組織的節點或信息片段的集合。DOM是基於樹的，DOM相對SAX來說簡單,耗內存...

本次學習目標：了解DOM解析XML ，並用DOM解析谷歌提供的天氣 

谷歌提供的天氣接口是 http://www.google.com/ig/api?hl=zh_CN&weather=wuhan   這個接口末尾是wuhan 即 "武漢" 的拼音,依次類推，北京的查詢方式是把後面拼音換成beijing就行了，這個接口是查詢武漢四天的天氣。

根元素(Element)是 xml_api_reply 即樹的根 然後往裡面擴展。

我要獲取節點forecas_conditions中的數據 

DOM初始工作需要幾個函數

DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = builderFactory.newDocumentBuilder();
Document document = builder.parse(new InputSource(new InputStreamReader(lianJie(strUrl) )));

然後通過Document對象解析XML，解析XML時會用到節點,並取得他的值 用到類 NodeList  ,Node. 下面開始上我的程序 

1. package com.study.weather;  
2.   
3. import java.io.IOException;  
4. import java.io.InputStream;  
5. import java.io.InputStreamReader;  
6. import java.net.HttpURLConnection;  
7. import java.net.URL;  
8.   
9. import javax.xml.parsers.DocumentBuilder;  
10. import javax.xml.parsers.DocumentBuilderFactory;  
11. import javax.xml.parsers.ParserConfigurationException;  
12.   
13. import org.w3c.dom.Document;  
14. import org.w3c.dom.Element;  
15. import org.w3c.dom.Node;  
16. import org.w3c.dom.NodeList;  
17. import org.xml.sax.InputSource;  
18. import org.xml.sax.SAXException;  
19.   
20. public class Weather  
21. {  
22.   
23.     public InputStream lianJie(String strUrl) throws IOException  
24.     {  
25.         URL url = new URL(strUrl);  
26.         HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();  
27.         InputStream is = urlConnection.getInputStream();  
28.           
29.           
30.         if(is!=null)  
31.         {  
32.             return is;  
33.         }  
34.         return null;  
35.     }  
36.       
37.     public void resolutionXML(String strUrl) throws ParserConfigurationException, SAXException, IOException  
38.     {  
39.         WeatherData wd = new WeatherData();  
40.         DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();  
41.         DocumentBuilder builder = builderFactory.newDocumentBuilder();  
42.         Document document = builder.parse(new InputSource(new InputStreamReader(lianJie(strUrl) )));  
43.           
44.         // 得到xml_api_reply    
45.         Element rootElement = document.getDocumentElement();  
46.         System.out.println(rootElement.getNodeName());  
47.         Node weatherNode =  rootElement.getElementsByTagName("weather").item(0);  
48.           
49. //      Node weatherNode = rootElement.getFirstChild();   
50.         System.out.println(weatherNode.getNodeName());  
51.         // 得到weather    
52. //      Node nodeWeather = weatherNode.getChildNodes();   
53.   
54.         // 得到weather下節點數組   
55.         NodeList nodeForecastWeathers =  weatherNode.getChildNodes();  
56.           
57.         // 遍歷weather下的節點   
58.         for(int i=0; i<nodeForecastWeathers.getLength(); i++)  
59.         {  
60.               
61.             Node nodeForecastWeather = nodeForecastWeathers.item(i);  
62.             // 篩選節點  找名稱為 forecast_conditions 節點   
63.             if(nodeForecastWeather.getNodeType()==Node.ELEMENT_NODE  
64.                     &&nodeForecastWeather.getNodeName().equals("forecast_conditions"))  
65.             {  
66.                         // 建立forecast_conditions下節點數組   
67.                         NodeList nodeListForecastConditions =  nodeForecastWeather.getChildNodes();  
68.                           
69.                         for(int j=0; j<nodeListForecastConditions.getLength(); j++)  
70.                         {  
71.                             //day_of_week low high condition   
72.                             Node data = nodeListForecastConditions.item(j);  
73.                         if(data.getNodeName().equals("day_of_week"))  
74.                         {  
75.                             wd.setDayOfWeek(data.getAttributes().getNamedItem("data").getNodeValue());  
76.                         }  
77.                         else if(data.getNodeName().equals("low"))  
78.                         {  
79.                             wd.setLow(data.getAttributes().item(0).getNodeValue());  
80.                         }  
81.                         else if(data.getNodeName().equals("high"))  
82.                         {  
83.                             wd.setHigh(data.getAttributes().item(0).getNodeValue());  
84.                         }  
85.                         else if(data.getNodeName().equals("condition"))  
86.                         {  
87.                             wd.setConditionData(data.getAttributes().item(0).getNodeValue());  
88.                         }  
89.                         }  
90.                         System.out.println(wd.printWeatheaInfo());  
91.                       
92.                 }  
93.             }  
94.           
95.         }  
96.               
97.           
98.       
99.           
100.       
101.     public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException  
102.     {  
103.         Weather weather = new Weather();  
104.         weather.resolutionXML("http://www.google.com/ig/api?hl=zh_CN&weather=wuhan");  
105.    
106.     }  
107.     class WeatherData  
108.     {  
109.         String dayOfWeek;  
110.         String low;  
111.         String high;  
112.         String conditionData;  
113.         public void setDayOfWeek(String dayOfWeek)  
114.         {  
115.             this.dayOfWeek = dayOfWeek;  
116.         }  
117.         public void setLow(String low)  
118.         {  
119.             this.low = low;  
120.         }  
121.   
122.         public void setHigh(String high)  
123.         {  
124.             this.high = high;  
125.         }  
126.   
127.         public void setConditionData(String conditionData)  
128.         {  
129.             this.conditionData = conditionData;  
130.         }  
131.           
132.         public String printWeatheaInfo()  
133.         {  
134.             return dayOfWeek+"\n"+"溫度: "+low+"~~"+high+"  \n天氣情況: "+conditionData;  
135.         }  
136.     }  
137. }

  這個是執行結果,完全解析正確