android dom解析相关理解

DOM解析XML 
DOM是Document Object Model的缩写,即文档对象模型.DOM解析器是通过将XML文档解析成树状模型并将其放入内存来完成解析工作的,而后对文档的操作都是在这个树状模型上完成.这个在内存中的文档是实际文档大小的几倍.好处是结构清晰,操作方便,坏处是耗费系统资源.要使用DOM方式来解析xml,需引入下面两个包: 
importjavax.xml.parsers.*;//包含DOM解析器和SAX解析器的具体实现 
import org.w3c.dom.*;//定义了W3C制定的DOM接口 
具体思路: 
*首先创建一个DocumentBuilderFactory实例, 
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); 

*利用DocumentBuilderFactory实例创建DocumentBuilder, 
DocumentBuilder builder = factory.newDocumentBuilder(); 
*然后加载xml文档(Document), 
Document doc = builder.parse(getAssets().open("xml/student.xml")); 
*然后获取文档的根节点(Element), 
Element root = doc.getDocumentElement(); 
*然后获取根节点中所有子节点的列表(NodeList), 
NodeListnodeList = root.getElementsByTagName("student"); 
*然后再获取子节点列表中需获取的节点. 
**************************************相关代码***************** 

 

 1 //student是一个实体类，里面有name，age参数，构造方法，和getter and setter方法，tostring输出； 

 2 public class DomParserActivity extends Activity { 

 3 private TextView mtextview; 

 4 private ListView mlistview; 

 5 @Override 

 6 protected void onCreate(Bundle savedInstanceState) { 

 7 

 8 super.onCreate(savedInstanceState); 

 9 setContentView(R.layout.domparser); 

10 mtextview = (TextView) findViewById(R.id.textView1); 

11 mlistview = (ListView) findViewById(R.id.listView1); 

12 mtextview.setText("dom解析xml"); 

13 List<Student> list = parserxml(); 

14 ArrayAdapter< Student> adapter = new ArrayAdapter<Student>(this,android.R.layout.simple_expandable_list_item_1,list); 

15 mlistview.setAdapter(adapter); 

16 

17 } 

18 private List<Student> parserxml() { 

19 List<Student> list = new ArrayList<Student>(); 

20 try { 

21 //获取工厂实例 

22 DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 

23 //获取解析器实例 

24 DocumentBuilder db; 

25 

26 db = dbf.newDocumentBuilder(); 

27 

28 //// 用解析器解析Xml， 放于src下面 

29 Document doc = db.parse(DomParserActivity.this.getClassLoader().getResourceAsStream("student.xml")); 

30 //获取Document根节点 

31 Element ele = doc.getDocumentElement(); 

32 //拿到某个标签的节点列表 

33 NodeList nodelist = ele.getElementsByTagName("student"); 

34 int length = nodelist.getLength(); 

35 Student stu = null; 

36 //遍历节点列表 

37 for(int i=0;i<length;i++){ 

38 stu = new Student(); 

39 Element stuele = (Element) nodelist.item(i); 

40     stu.setId(Integer.parseInt(stuele.getAttribute("id"))); 

41   //拿到<student>标签的子节点列表 

42     NodeList childlist = stuele.getChildNodes(); 

43     int childlength = childlist.getLength(); 

44   //遍历子节点列表 

45     for(int j=0;j<childlength;j++){ 

46     Node node = childlist.item(j); 

47    if(node.getNodeType()==Node.ELEMENT_NODE){ 

48      Element element = (Element) node; 

49      if("name".equals(element.getNodeName())){ 

50     stu.setName(element.getFirstChild().getNodeValue()); 

51     Log.i("TAG", ""+stu.getName()); 

52      } 

53      else if("age".equals(element.getNodeName())){ 

54     stu.setAge(Integer.valueOf(element.getAttribute("value"))); 

55     

56      } 

57      

58     } 

59    } 

60     list.add(stu); 

61 } 

62 } 

63 catch (ParserConfigurationException e) { 

64 // TODO Auto-generated catch block 

65 e.printStackTrace(); 

66 } catch (SAXException e) { 

67 // TODO Auto-generated catch block 

68 e.printStackTrace(); 

69 } catch (IOException e) { 

70 // TODO Auto-generated catch block 

71 e.printStackTrace(); 

72 } 

73 

74 

75 return list; 

76 

77 } 

78   

79 }