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;
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;
9. import javax.xml.parsers.DocumentBuilder;
10. import javax.xml.parsers.DocumentBuilderFactory;
11. import javax.xml.parsers.ParserConfigurationException;
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;
20. public class Weather
21. {
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();
30. if(is!=null)
31. {
32. return is;
33. }
34. return null;
35. }
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) )));
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);
49. // Node weatherNode = rootElement.getFirstChild();
50. System.out.println(weatherNode.getNodeName());
51. // 得到weather
52. // Node nodeWeather = weatherNode.getChildNodes();
54. // 得到weather下節點數組
55. NodeList nodeForecastWeathers = weatherNode.getChildNodes();
57. // 遍歷weather下的節點
58. for(int i=0; i<nodeForecastWeathers.getLength(); i++)
59. {
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();
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());
92. }
93. }
95. }
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");
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. }
122. public void setHigh(String high)
123. {
124. this.high = high;
125. }
127. public void setConditionData(String conditionData)
128. {
129. this.conditionData = conditionData;
130. }
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