SAX解析XML文檔之二

 

<?xml version="1.0" encoding="UTF-8"?>
<books>
	<book id="12">
		<name>thinking in java</name>
		<price>85.5</price>
	</book>
	<book id="15">
		<name>Spring in Action</name>
		<price>39.0</price>
	</book>
</books>

 

 

package cn.sisy.xml;

public class Book {
	private int id;
	private String name;
	private float price;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public float getPrice() {
		return price;
	}
	public void setPrice(float price) {
		this.price = price;
	}
	@Override
	public String toString(){
		return this.id+":"+this.name+":"+this.price;
	}
}

 

 

 

package cn.sisy.xml;

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

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 cn.sisy.xml.Book;

public class SaxParseService extends DefaultHandler{
	private List<Book> books = null;
	private Book book = null;
	private String preTag = null;//作用是記錄解析時的上一個節點名稱
	
	public List<Book> getBooks(InputStream xmlStream) throws Exception{
		SAXParserFactory factory = SAXParserFactory.newInstance();
		SAXParser parser = factory.newSAXParser();
		SaxParseService handler = new SaxParseService();
		parser.parse(xmlStream, handler);
		return handler.getBooks();
	}
	
	public List<Book> getBooks(){
		return books;
	}
	
	@Override
	public void startDocument() throws SAXException {
		books = new ArrayList<Book>();
	}

	@Override
	public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
		if("book".equals(qName)){
			book = new Book();
			book.setId(Integer.parseInt(attributes.getValue(0)));
		}
		preTag = qName;//將正在解析的節點名稱賦給preTag
	}

	@Override
	public void endElement(String uri, String localName, String qName)
			throws SAXException {
		if("book".equals(qName)){
			books.add(book);
			book = null;
		}
		preTag = null;/**當解析結束時置爲空。這裏很重要，例如，當圖中畫3的位置結束後，會調用這個方法
		，如果這裏不把preTag置爲null，根據startElement(....)方法，preTag的值還是book，當文檔順序讀到圖
		中標記4的位置時，會執行characters(char[] ch, int start, int length)這個方法，而characters(....)方
		法判斷preTag!=null，會執行if判斷的代碼，這樣就會把空值賦值給book，這不是我們想要的。*/
	}
	
	@Override
	public void characters(char[] ch, int start, int length) throws SAXException {
		if(preTag!=null){
			String content = new String(ch,start,length);
			if("name".equals(preTag)){
				book.setName(content);
			}else if("price".equals(preTag)){
				book.setPrice(Float.parseFloat(content));
			}
		}
	}
	
}

 

 

package cn.sisy.xml;

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

import junit.framework.TestCase;

import cn.sisy.xml.SaxParseService;
import cn.sisy.xml.Book;

public class ParseTest extends TestCase{

	public void testSAX() throws Throwable{
		SaxParseService sax = new SaxParseService();
		//InputStream input = this.getClass().getClassLoader().getResourceAsStream("book.xml");
		InputStream input = new FileInputStream(new File("book.xml"));
		List<Book> books = sax.getBooks(input);
		for(Book book : books){
			System.out.println(book.toString());
		}
	}
}

 

代碼轉載自：http://sinye.iteye.com/blog/763895