Java解析XML（一）、SAX

偏执的太偏执、 2022-06-15 00:16 205阅读 0赞

package xml;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.util.List;
    
    import javax.xml.parsers.SAXParser;
    import javax.xml.parsers.SAXParserFactory;
    
    import model.Book;
    
    /**
     * 使用SAX解析XML文件
     */
    public class SaxHelper {
    	
    	private static SAXParserFactory spf;
    
    	/**
    	 * 使用SAX方式解析XML文件
    	 * @param is XML文件输入流
    	 * @return 
    	 */
    	public static List<Book> saxReader(InputStream is) {
    		try {
    			if (spf == null)
    			 spf = SAXParserFactory.newInstance();
    			SAXParser saxParser = spf.newSAXParser(); 
    			XmlContentHandler xmlContentHandler = new XmlContentHandler();
    			saxParser.parse(is, xmlContentHandler);
    			return xmlContentHandler.getBooks();
    		} catch (Exception e) {
    			e.printStackTrace();
    			return null;
    		} finally {
    			try {
    				is.close();
    			} catch (IOException e) {
    				e.printStackTrace();
    			}
    		}
    	}
    	
    }
    
    
    package xml;
    
    import java.util.ArrayList;
    import java.util.List;
    
    import model.Book;
    
    import org.xml.sax.Attributes;
    import org.xml.sax.SAXException;
    import org.xml.sax.helpers.DefaultHandler;
    
    import util.DateUtils;
    
    /**
     * SAX解析XML文件的事件处理器
     */
    public class XmlContentHandler extends DefaultHandler {
    	
    	private Book book;	//保存每一个节点的对象
    	
    	private List<Book> books;	//保存已解析好的节点对象
    	
    	private String preTag;		//保存当前正在解析的节点标签名
    	
    	@Override
    	public void startDocument() throws SAXException {
    		System.out.println("开始解析文档...");
    		books = new ArrayList<Book>();
    	}
    	
    	@Override
    	public void startElement(String uri, String localName, String name,
    			Attributes attributes) throws SAXException {
    		if (name.equals("book") && book == null) {
    			book = new Book();
    			book.setIsbn(attributes.getValue("", "isbn"));
    		}
    		
    		preTag = name;	//记录当前开始节点名
    	}
    	
    	@Override
    	public void characters(char[] ch, int start, int length)
    			throws SAXException {
    		if (book != null && preTag != null && !"book".equals(preTag) && !"books".equals(preTag)) {
    			String data = new String(ch,start,length);
    			if (!"".equals(data.trim())) {
    				if ("name".equals(preTag)) {
    					book.setName(data);
    				} else if ("author".equals(preTag)) {
    					book.setAuthor(data);
    				} else if ("publishing".equals(preTag)) {
    					book.setPublishing(data);
    				} else if ("pubdate".equals(preTag)) {
    					book.setPubdate(DateUtils.string2Date("yyyy-mm-dd", data));
    				} else if ("price".equals(preTag)) {
    					book.setPrice(Double.parseDouble(data));
    				}
    			}
    		}
    	}
    	
    	@Override
    	public void endElement(String uri, String localName, String name)
    			throws SAXException {
    		if ("book".equals(name) && book != null) {
    			books.add(book);
    			book = null;	//一个节点的结束,代表一本书的信息解析完成,所以要将book设为null
    		}
    		preTag = null;		//同时将当前书的节点设为null
    	}
    	
    	@Override
    	public void endDocument() throws SAXException {
    		System.out.println("XML文件解析结束...");
    		System.out.println("结果:" + books);
    	}
    
    	/**
    	 * 获得解析后的数据
    	 * @return
    	 */
    	public List<Book> getBooks() {
    		return books;
    	}
    	
    }
    
    
    package model;
    
    import java.util.Date;
    
    /**
     * 图书
     */
    public class Book {
    
    	/**
    	 * 图书编号
    	 */
    	private String isbn;
    	
    	/**
    	 * 书名
    	 */
    	private String name;
    	
    	/**
    	 * 作者
    	 */
    	private String author;
    	
    	/**
    	 * 出版社
    	 */
    	private String publishing;
    	
    	/**
    	 * 发布时间
    	 */
    	private Date pubdate;
    	
    	/**
    	 * 价格
    	 */
    	private double price;
    
    	public String getIsbn() {
    		return isbn;
    	}
    
    	public void setIsbn(String isbn) {
    		this.isbn = isbn;
    	}
    
    	public String getName() {
    		return name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    	public String getAuthor() {
    		return author;
    	}
    
    	public void setAuthor(String author) {
    		this.author = author;
    	}
    
    	public String getPublishing() {
    		return publishing;
    	}
    
    	public void setPublishing(String publishing) {
    		this.publishing = publishing;
    	}
    
    	public Date getPubdate() {
    		return pubdate;
    	}
    
    	public void setPubdate(Date pubdate) {
    		this.pubdate = pubdate;
    	}
    
    	public double getPrice() {
    		return price;
    	}
    
    	public void setPrice(double price) {
    		this.price = price;
    	}
    	
    	public String toString() {
    		return "name: " + name + " isbn: " + isbn + " author: " + author
    				+ " publishing: " + publishing + " pubdate: " + pubdate
    				+ " price: " + price;
    	}
    }

<?xml version="1.0" encoding="UTF-8"?>
    <books>
    	
    	<book isbn="9787121025389">
    		<name>JAVA面向对象编程</name>
    		<author>孙卫琴</author>
    		<publishing>电子工业出版社</publishing>
    		<pubdate>2006-07-01</pubdate>
    		<price>50.60</price>
    	</book>
    	<book isbn="9787111349662">
    		<name>深入理解Java虚拟机：JVM高级特性与最佳实践</name>
    		<author>周志明</author>
    		<publishing>机械工业出版社</publishing>
    		<pubdate>2011-07-01</pubdate>
    		<price>46.20</price>
    	</book>
    	<book isbn="9787508338408">
    		<name>Java网络编程（第3版）</name>
    		<author>（英）哈诺德 著 朱涛江，林剑 译</author>
    		<publishing>中国电力出版社</publishing>
    		<pubdate>2005-11-01</pubdate>
    		<price>63.80</price>
    	</book>
    	<book isbn="9787508379661">
    		<name>Java经典实例（第2版）</name>
    		<author>（美）达尔文（Darwin，F.I） 著 关丽荣，张晓坤 译</author>
    		<publishing>中国电力出版社</publishing>
    		<pubdate>2009-02-01</pubdate>
    		<price>72.10</price>
    	</book>
    	<book isbn="9787111213826">
    		<name>Java编程思想（第4版）</name>
    		<author>（美）埃克尔 著 陈昊鹏 译</author>
    		<publishing>机械工业出版社</publishing>
    		<pubdate>2007-06-01</pubdate>
    		<price>74.50</price>
    	</book>
    	<book isbn="9787508344980">
    		<name>Head First Java（中文版）（第2版）</name>
    		<author>（美）塞若（Sierra，K.），（美）贝茨（Bates，B.） 著 O’Reilly Taiwan公司 译 张然，等 编</author>
    		<publishing>中国电力出版社</publishing>
    		<pubdate>2007-02-01</pubdate>
    		<price>55.20</price>
    	</book>
    	<book isbn="9787111231837">
    		<name>数据结构与算法分析：Java语言描述（第2版）</name>
    		<author>（美）韦斯（Weiss，M.A.） 著 冯舜玺 译</author>
    		<publishing>机械工业出版社</publishing>
    		<pubdate>2009-01-01</pubdate>
    		<price>41.20</price>
    	</book>
    </books>