XML解析的三种方式

参考：http://blog.csdn.net/liuhe688/article/details/6415593

首先定义一个接口

package com.lei.xml;

import java.io.InputStream;
import java.util.List;

public interface XMLParser {
	// 解析xml
	<T> List<T> xmlParse(InputStream is);

	//构造xml
	<T> String xmlSerializer(List<T> list);
}

1. PULL解析

解析速度快，事件处理，不会预加载整个文档

package com.lei.xml;

import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.List;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlSerializer;

import android.util.Xml;

public class PullParse implements XMLParser {

	public static PullParse getInstance() {
		return new PullParse();
	}

	public <T> List<T> xmlParse(InputStream is) {
		List<Book> list = null;
		Book book = null;
		XmlPullParser parser = Xml.newPullParser();
		// XmlPullParser parser =
		// XmlPullParserFactory.newInstance().newPullParser();
		try {
			parser.setInput(is, "utf-8");

			int type = parser.getEventType();
			while (type != XmlPullParser.END_DOCUMENT) {//整个xml结束标签，出口

				switch (type) {
				case XmlPullParser.START_DOCUMENT://整个xml开始标签，入口
					list = new ArrayList<Book>();
					break;

				case XmlPullParser.START_TAG://子开始标签
					if (parser.getName().equals("book")) {
						book = new Book();
					} else if (parser.getName().equals("id")) {
						type = parser.next();
						book.setId(Integer.parseInt(parser.getText()));

					} else if (parser.getName().equals("name")) {
						type = parser.next();
						book.setName(parser.getText());
					}
					break;
				case XmlPullParser.END_TAG://子结束标签
					if (parser.getName().equals("book")) {
						list.add(book);
					}
					break;
				}
				type = parser.next();
			}

		} catch (XmlPullParserException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}

		return (List<T>) list;
	}

	public <T> String xmlSerializer(List<T> list) {
		List<Book> lists = (List<Book>) list;
		XmlSerializer serializer = Xml.newSerializer();
		try {
			serializer.startDocument("utf-8", true);
			serializer.setOutput(new StringWriter());
			serializer.startTag("", "books");

			for (Book book : lists) {
				serializer.startTag("", "book");

				serializer.attribute("", "id", String.valueOf(book.getId()));

				serializer.startTag("", "name");
				serializer.text(book.getName());
				serializer.endTag("", "name");

				serializer.endTag("", "book");
			}

			serializer.endTag("", "books");
			serializer.endDocument();
		} catch (IllegalArgumentException e) {
			e.printStackTrace();
		} catch (IllegalStateException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}

		return serializer.toString();
	}

}

2. SAX解析

树形结构，速度款，占用内存少，会预加载整个文档，适用于文档较小。

package com.lei.xml;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.ParserConfigurationException;
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 com.lei.utils.Logs;

public class SaxParse implements XMLParser {

	public static SaxParse getInstance() {
		return new SaxParse();
	}

	/**
	 * 解析xml
	 */
	public <T> List<T> xmlParse(InputStream is) {
		try {
			SAXParser parser = SAXParserFactory.newInstance().newSAXParser();
			MyXmlHandler handler = new MyXmlHandler();
			parser.parse(is, handler);

			return (List<T>) handler.getBookList();
		} catch (ParserConfigurationException e) {
			e.printStackTrace();
		} catch (SAXException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 生成xml
	 */
	public <T> String xmlSerializer(List<T> list) {
		return null;
	}

	class MyXmlHandler extends DefaultHandler {
		List<Book> list;
		Book book;
		StringBuilder builder;

		public List<Book> getBookList() {

			return list;
		}

		// 入口，开始
		@Override
		public void startDocument() throws SAXException {
			super.startDocument();
			Logs.v("startDocument");
			list = new ArrayList<Book>();
			builder = new StringBuilder();
		}

		// 出口，结束
		@Override
		public void endDocument() throws SAXException {
			super.endDocument();
			Logs.v("endDocument");

		}

		// 开始解析开始标签
		@Override
		public void startElement(String uri, String localName, String qName,
				Attributes attributes) throws SAXException {
			super.startElement(uri, localName, qName, attributes);
			Logs.v("startElement  " + "uri " + uri + " localName " + localName
					+ " qName  " + qName);
			if ("book".equals(localName)) {
				book = new Book();
			}
			builder.setLength(0);// 每次豆浆builder清空

		}

		// 结束标签
		@Override
		public void endElement(String uri, String localName, String qName)
				throws SAXException {
			super.endElement(uri, localName, qName);
			Logs.v("endElement  " + "uri " + uri + " localName " + localName
					+ " qName  " + qName);
			if ("id".equals(localName)) {
				book.setId(Integer.parseInt(builder.toString()));
			} else if ("name".equals(localName)) {
				book.setName(builder.toString());
			} else if ("book".equals(localName)) {
				list.add(book);
			}

		}

		// 获取子标签的内容
		@Override
		public void characters(char[] ch, int start, int length)
				throws SAXException {
			super.characters(ch, start, length);
			builder.append(ch, start, length);
			Logs.v("characters " + new String(ch, start, length));
		}

	}

}

3.DOM解析

预先加载整个文档，占用内存大，不推荐使用

package com.lei.xml;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class DomParse implements XMLParser {

	public static DomParse getInstance(){
		return new DomParse();
	}

	public <T> List<T> xmlParse(InputStream is) {
		List<Book> list = new ArrayList<Book>();
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
		try {
			DocumentBuilder builder = factory.newDocumentBuilder();
			Document doc = builder.parse(is);
			Element element = doc.getElementById("book");
			NodeList nodeList = element.getChildNodes();
			Book book = null;
			for (int i = 0; i < nodeList.getLength(); i++) {
				Node node = nodeList.item(i);
				book = new Book();

				NodeList details = node.getChildNodes();
				for (int j = 0; j < details.getLength(); j++) {
					if (node.getLocalName().equals("id")) {
						book.setId(Integer.parseInt(node.getNodeValue()));
					} else if (node.getLocalName().equals("name")) {
						book.setName(node.getNodeValue());
					}
				}
				list.add(book);
			}

		} catch (ParserConfigurationException e) {
			e.printStackTrace();
		} catch (SAXException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}

		return (List<T>) list;
	}

	public <T> String xmlSerializer(List<T> list) {
		return null;
	}

}

使用：

在 assets下放了一个books.xml

private void parseXmBySax() {
		try {
			InputStream is = getAssets().open("books.xml");
			List<Book> list = new SaxParse().xmlParse(is);
			for (Book book : list) {
				mShowTv.append(book.toString());
			}

		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	private void parseXmByPull() {
		InputStream is = null;
		try {
			is = getAssets().open("books.xml");
		} catch (IOException e) {
			e.printStackTrace();
		}
		List<Book> list = PullParse.getInstance().xmlParse(is);
		for (Book book : list) {
			mShowTv.append(book.toString());
		}
	}

	private void parseXmlByDom() {
		InputStream is = null;
		try {
			is = getAssets().open("books.xml");
		} catch (IOException e) {
			e.printStackTrace();
		}
		List<Book> list = new SaxParse().xmlParse(is);
		for (Book book : list) {
			mShowTv.append(book.toString());
		}
	}