SAX解析XML并把节点值保存到相应的对象中

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一、book.xml:

<?xml version="1.0" encoding="UTF-8"?>
<bookstore>
	<book id="1">
		<name>冰与火之歌</name>
		<author>乔治马丁</author>
		<year>2014</year>
		<price>89</price>
	</book>
	<book id="2">
		<name>安徒生童话</name>
		<year>2004</year>
		<price>77</price>
		<language>English</language>
	</book>
</bookstore>



二、hnadler类:

import java.util.ArrayList;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import com.imooc.entity.Book;

public class SAXParserHandler extends DefaultHandler {
	String value = null;
	Book book = null;
	private ArrayList<Book> bookList = new ArrayList<Book>();
	public ArrayList<Book> getBookList() {
		return bookList;
	}

	int bookIndex = 0;
	/**
	 * 用来标识解析开始
	 */
	@Override
	public void startDocument() throws SAXException {
		// TODO Auto-generated method stub
		super.startDocument();
		System.out.println("SAX解析开始");
	}
	
	/**
	 * 用来标识解析结束
	 */
	@Override
	public void endDocument() throws SAXException {
		// TODO Auto-generated method stub
		super.endDocument();
		System.out.println("SAX解析结束");
	}
	
	/**
	 * 解析xml元素
	 */
	@Override
	public void startElement(String uri,String localName,String qName,Attributes attributes) throws SAXException {
		//调用DefaultHandler类的startElement方法
		super.startElement(uri,localName,qName,attributes);
		if (qName.equals("book")) {
			bookIndex++;
			//创建一个book对象
			book = new Book();
			//开始解析book元素的属性
			System.out.println("======================开始遍历某一本书的内容=================");
//			//已知book元素下属性名称,根据属性名称获取属性值
//			String value = attributes.getValue("id");
//			System.out.println("book的属性值是:" + value);
			//不知道book元素下属性名称以及个数,如何获取属性名以及属性值
			int num = attributes.getLength();
			for(int i = 0; i < num; i++){
				System.out.print("book元素的第" + (i + 1) +  "个属性名是:"
						+ attributes.getQName(i));
				System.out.println("---属性值是:" + attributes.getValue(i));
				if (attributes.getQName(i).equals("id")) {
					book.setId(attributes.getValue(i));
				}
			}
		}
		else if (!qName.equals("name") && !qName.equals("bookstore")) {
			System.out.print("节点名是:" + qName + "---");
		}
	}
	
	@Override
	public void endElement(String uri,String qName)
			throws SAXException {
		//调用DefaultHandler类的endElement方法
		super.endElement(uri,qName);
		//判断是否针对一本书已经遍历结束
		if (qName.equals("book")) {
			bookList.add(book);
			book = null;
			System.out.println("======================结束遍历某一本书的内容=================");
		}
		else if (qName.equals("name")) {
			book.setName(value);
		}
		else if (qName.equals("author")) {
			book.setAuthor(value);
		}
		else if (qName.equals("year")) {
			book.setYear(value);
		}
		else if (qName.equals("price")) {
			book.setPrice(value);
		}
		else if (qName.equals("language")) {
			book.setLanguage(value);
		}
	}	
	
	@Override
	public void characters(char[] ch,int start,int length)
			throws SAXException {
		// TODO Auto-generated method stub
		super.characters(ch,start,length);
		value = new String(ch,length);
		if (!value.trim().equals("")) {
			System.out.println("节点值是:" + value);
		}
	}
}


三、测试类:

import java.io.IOException;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import com.imooc.entity.Book;
import com.imooc.handler.SAXParserHandler;

public class SAXTest {
	public static void main(String[] args) {
		//获取一个SAXParserFactory的实例
<span style="white-space:pre">		</span>SAXParserFactory factory = SAXParserFactory.newInstance();
<span style="white-space:pre">		</span>//通过factory获取SAXParser实例
<span style="white-space:pre">		</span>try {
<span style="white-space:pre">			</span>SAXParser parser = factory.newSAXParser();
<span style="white-space:pre">			</span>//创建SAXParserHandler对象
			SAXParserHandler handler = new SAXParserHandler();
			parser.parse("books.xml",handler);
			System.out.println("~!~!~!共有" + handler.getBookList().size()
					+ "本书");
			for (Book book : handler.getBookList()) {
				System.out.println(book.getId());
				System.out.println(book.getName());
				System.out.println(book.getAuthor());
				System.out.println(book.getYear());
				System.out.println(book.getPrice());
				System.out.println(book.getLanguage());
				System.out.println("----finish----");
			}
		} 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();
		}
	}

}

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