android sax解析本地XML和网络XML

  最近开始学android,学到解析sax解析网络XML文档时,真是让我无语了。总给我提示文档输入流InputStream空指针异常。我单独测试网络获取XML文件的类时是没有问题的，足足耗费了我两天的时间我都找不到事哪里的问题。网上各种查，终于发现了原来是AndroidMainfest.xml用户网络权限  <uses-permission android:name="android.permission.INTERNET" />没有加。ri了狗了。

   还有就是解析本地XML时XML文件应放在res目录下的assets下，然后使用InputStream inputSteam = MainActivity.this.getClassLoader().getResourceAsStream("person.xml");获取文件输入流。sax解析XML,首先要实现一个继承DefaultHandler的类，实现这个类后我们要重写四个方法，分别是startDocument();startElement();，characters();以及endElement();。四个方法会被默认调用，startDocument()在读到XML文件时被调用，startElement()在读到文件的一个节点时被调用，character()在读到文件节点中的属性时被调用。，endElement()在一个节点结束标志时被调用。我们应分别各个方法里添加一些操作。这个类实现后还应该再实现一个调用这个类中方法的类(我这么说可能不准确，只是我这么理解的)。生成一个SAXParserFactory工厂类对象，然后由这个工厂对象构造一个SaxParser类的对象，再由这个对象来调用XML文档解析的对象。

一.解析本地XML

MyHandler类，用于文档解析

public class MyHandler extends DefaultHandler { private List<person> persons = null; private Person person; private String tagName; public List<person> getPersons() { return persons; } public MyHandler() { // TODO Auto-generated constructor stub } @Override public void startDocument() throws SAXException { // TODO Auto-generated method stub persons = new ArrayList<person>(); } @Override public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { // TODO Auto-generated method stub this.tagName = localName; if(tagName.equals("person")){ person = new Person(); person.setId(attributes.getValue(0)); } } @Override public void characters(char[] ch, int start, int length) throws SAXException { // TODO Auto-generated method stub if(this.tagName != null){ String data = new String(ch,start,length); if(this.tagName.equals("name")){ person.setName(data); }else if(this.tagName.equals("age")){ person.setAge(data); } } } @Override public void endElement(String uri, String localName, String qName) throws SAXException { // TODO Auto-generated method stub if(localName.equals("person")){ persons.add(person); } this.tagName = null; } }

 

SaxService这个类对来调用MyHanler

public class SaxService { public SaxService() { // TODO Auto-generated constructor stub } public static List<person> readXML(InputStream inputStream){ List<person> persons = null; SAXParserFactory factory = SAXParserFactory.newInstance(); try { SAXParser parser = factory.newSAXParser(); MyHandler handler = new MyHandler(); parser.parse(inputStream,handler); persons = handler.getPersons(); inputStream.close(); } catch (ParserConfigurationException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (SAXException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return persons; } } textarea>

public class MainActivity extends ActionBarActivity { private Button button; private ListView listView; private ArrayAdapter<person> adapter = null; private List<person> list = null; private String path = "http://192.168.0.101:8080/http/person.xml"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); button = (Button)findViewById(R.id.button1); listView = (ListView)findViewById(R.id.listview); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub // InputStream inputStream = HttpUtils.getXML(path); InputStream inputStream = MainActivity.this.getClassLoader().getResourceAsStream("person.xml"); list = SaxService.readXML(inputStream); adapter = new ArrayAdapter<person>(MainActivity.this,android.R.layout.simple_expandable_list_item_1,list); listView.setAdapter(adapter); } }); } </person></person></person>