DOM/SAX/PULL解析XML
1. 代码结构
InterfaceXMLParseService 解析接口, DOM/SAX/PULL分别实现这个接口
XML来源是assets目录下的persons.xml文件
2. 代码
//persons.xml <?xml version="1.0" encoding="utf-8"?> <persons> <person> <id>1</id> <name>Tom</name> <age>12</age> </person> <person> <id>2</id> <name>May</name> <age>14</age> </person> <person> <id>3</id> <name>Joe</name> <age>13</age> </person> </persons>
//XMLParserService package mirror.android.XMLParseActivity; import java.io.IOException; import java.io.InputStream; import mirror.android.Services.DOMParseService; import mirror.android.Services.PULLParseService; import mirror.android.Services.SAXParseService; import mirror.android.resolvexml.R; import android.app.Activity; import android.os.Bundle; public class XMLParseActivity extends Activity{ @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_xmlparse); try { InputStream in1 = getAssets().open("persons.xml"); InputStream in2 = getAssets().open("persons.xml"); InputStream in3 = getAssets().open("persons.xml"); DOMParseService domParseService = new DOMParseService(); domParseService.getPersonsByParseXML(in1); SAXParseService saxParseService = new SAXParseService(); saxParseService.getPersonsByParseXML(in2); PULLParseService pullParseService = new PULLParseService(); pullParseService.getPersonsByParseXML(in3); } catch (IOException e) { e.printStackTrace(); } } }
//InterfaceXMLParserService.java package mirror.android.Services; import java.io.InputStream; public interface InterfaceXMLParseService { public void getPersonsByParseXML(InputStream is); }
//DOMParserService.java package mirror.android.Services; import java.io.InputStream; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import android.util.Log; /* DOM解析器在解析XML文档时，会把文档中的所有元素， 按照其出现的层次关系，解析成一个个Node对象(节点)。Node对象提供了一系列常量来代表结点的类型 当开发人员获得某个Node类型后，就可以把Node节点转换成相应节点对象(Node的子类对象)，以便于调用其特有的方法。 Node对象提供了相应的方法去获得它的父结点或子结点。编程人员通过这些方法就可以读取整个XML文档的内容、或添加、修改、删除XML文档的内容. 缺点： 一次性的完全加载整个xml文件，需要消耗大量的内存。 */ public class DOMParseService implements InterfaceXMLParseService{ @Override public void getPersonsByParseXML(InputStream is){ try { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db = dbf.newDocumentBuilder(); Document doc = db.parse(is); doc.getDocumentElement().normalize(); //得到根元素,这里是persons NodeList personNodes = doc.getElementsByTagName("person"); //Log.d("Mirror", personNodes.toString() + " its length is " + personNodes.getLength()); for (int i = 0; i < personNodes.getLength(); i++) { Element element_person = (Element)personNodes.item(i); Node node_id = element_person.getElementsByTagName("id").item(0); Node node_name = element_person.getElementsByTagName("name").item(0); Node node_age = element_person.getElementsByTagName("age").item(0); Log.d("DOMParse--->","Name: " + node_name.getFirstChild().getNodeValue() + ", Id: " + node_id.getFirstChild().getNodeValue() + ", age: "+ node_age.getFirstChild().getNodeValue()); } } catch (Exception e) { e.printStackTrace(); } } }
//SAXParserService.java package mirror.android.Services; import java.io.InputStream; import javax.xml.parsers.SAXParser; import javax.xml.parsers.SAXParserFactory; import org.xml.sax.Attributes; import org.xml.sax.SAXException; import org.xml.sax.helpers.DefaultHandler; import android.util.Log; //优点：SAX解析允许在读取文档的时候，即对文档进行处理，而不必等到整个文档装载完才会文档进行操作。 public class SAXParseService implements InterfaceXMLParseService { @Override public void getPersonsByParseXML(InputStream is) { try { SAXParserFactory factory = SAXParserFactory.newInstance(); SAXParser parser = factory.newSAXParser(); parser.parse(is, new saxHandler()); } catch (Exception e) { e.printStackTrace(); } } // 自定义一个handler实现DefaultHandler并 重写它的相关方法 private class saxHandler extends DefaultHandler{ private String currentTag = null; String str = ""; @Override public void startDocument() throws SAXException { //读到 <?xml version="1.0" encoding="utf-8"?> 时调用 } @Override public void endDocument() throws SAXException { } @Override public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { //if("person".equals(localName)); currentTag = localName; //Log.d("Mirror_startElement",localName); } @Override public void endElement(String uri, String localName, String qName) throws SAXException { //Log.d("Mirror_endElement",localName); if(localName.equals(currentTag)) currentTag = null; } @Override public void characters(char[] ch, int start, int length) throws SAXException { if("id".equals(currentTag)) str += "Id: " + new String(ch,start,length); if("name".equals(currentTag)) str += ",Name: " + new String(ch,start,length); if("age".equals(currentTag)){ str += ",Age: " + new String(ch,start,length); Log.d("SAXParse--->", str); str = ""; } } } }
//PULLParserService.java package mirror.android.Services; import java.io.InputStream; import org.xmlpull.v1.XmlPullParser; import org.xmlpull.v1.XmlPullParserFactory; import android.util.Log; //优点：不是一次加载，中途可以停止。 public class PULLParseService implements InterfaceXMLParseService { @Override public void getPersonsByParseXML(InputStream is) { String str = ""; try { XmlPullParserFactory factory = XmlPullParserFactory.newInstance(); XmlPullParser parser = factory.newPullParser(); parser.setInput(is,"utf-8"); //parser的几种事件类型 int type = parser.getEventType(); while(type != XmlPullParser.END_DOCUMENT){ String typeName = parser.getName(); switch (type) { case XmlPullParser.START_DOCUMENT: break; case XmlPullParser.START_TAG: if("person".equals(typeName)); else if("id".equals(typeName)) str += "Id: " + parser.nextText(); else if("name".equals(typeName)) str += ", name " + parser.nextText(); else if("age".equals(typeName)){ str += ", age " + parser.nextText(); Log.d("PULLParse--->", str); str = ""; } break; case XmlPullParser.END_TAG: break; default: break; } //Get next parsing event.最最重要的一步，pull解析中的特有的方法，解析下一个标签 type = parser.next(); } } catch (Exception e) { e.printStackTrace(); } } }
3. 打印结果
4. 项目地址
https://github.com/Mirrorhanyu/XMLParser
