SAX解析xml

1.创建事件处理程序（编写ContentHandler的实现类，一般集成自DefaultHandler类， 采用 adapter 模式）
2.创建SAX解析器
3.将事件处理程序分配到解析器
4.对文档进行解析，将每个事件发送给事件处理程序

XMl文档

<?xml version = "1.0" encoding = "UTF-8"?>
<books>
    <book bookno="001">
        <title> java 编程</title>
        <author> me </author>
        <price> 80 </price>
    </book>
    <book bookno="002">
        <title> android 编程</title>
        <author> me </author>
        <price> 70 </price>
    </book>
</books>

Book基类

public class Book {
    private String no;
    private String title;
    private String author;
    private Double price;

    public String getNo() {
        return no;
    }

    public void setNo(String no) {
        this.no = no;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public Double getPrice() {
        return price;
    }

    public void setPrice(double d) {
        this.price = d;
    }

    @Override
    public String toString() {
        return "book [no=" + no + ", title=" + title + ", author=" + author + ", price=" + price + "]";
    }

    public Book() {
        super();
        // TODO Auto-generated constructor stub
    }

    public Book(String no, String title, String author, Double price) {
        super();
        this.no = no;
        this.title = title;
        this.author = author;
        this.price = price;
    }

}

XMLParser接口

import java.util.List;

public interface XMLParser {
public List<Book> parseXML(String filename);

}

SaxHandler处理程序

/*
 * 
 * 提供事件回调方法
 * */
import java.util.ArrayList;
import java.util.List;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

public class MySaxHandler extends DefaultHandler {
    private String tag;
    private Book book;
    private List<Book> list;

    public List<Book> getList() {
        return list;
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        super.characters(ch, start, length);
        if (tag != null) {
            String str = new String(ch, start, length).trim();
            if (tag.equals("title")) {
                book.setTitle(str);
            }
            if (tag.equals("author")) {
                book.setAuthor(str);
            }
            if (tag.equals("price")) {
                book.setPrice(Double.parseDouble(str));
            }

        }
    }

    @Override
    public void endDocument() throws SAXException {
        super.endDocument();
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        super.endElement(uri, localName, qName);
        if (qName.equals("book")) {
            list.add(book);
            book = null;
        }
        tag = null;
    }

    @Override
    public void startDocument() throws SAXException {
        super.startDocument();
        list = new ArrayList<Book>();
    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

        super.startElement(uri, localName, qName, attributes);
        if (qName.equals("book")) {
            book = new Book();
            String no = attributes.getValue("bookno");
            book.setNo(no);

        }
        tag = qName;
    }

}

SaxParser 解析器

import java.io.FileInputStream;
import java.io.FileNotFoundException;
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.SAXException;

public class SaxParser implements XMLParser {

@Override
public List<Book> parseXML(String filename) {
List<Book> list = new ArrayList<Book>();
MySaxHandler handler = null;
//XML解析器
SAXParserFactory factory = SAXParserFactory.newInstance();
try {
// xml解析器
SAXParser parser = factory.newSAXParser();
//文件输入流
InputStream is = new FileInputStream(filename);
//处理程序
handler = new MySaxHandler();
//分配处理程序到解析器
parser.parse(is, handler);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
//提取在处理程序中得到的容器
list = handler.getList();
return list;
}

public static void main(String[] args) {
XMLParser parser = new SaxParser();
List<Book> list = parser.parseXML("src\book.xml");
System.out.println("SAX解析结果：");
for (Book book : list) {
System.out.println(book.toString());
}

}

}