Java xml解析（DOM、SAX）

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test.mxl

<?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>

封装成一个对象

package com.hz;/** * 封装book对象 *  * @author ztw * * 2016-12-20 */public class Book {    private String id;    private String name;    private double price;    public String getId() {        return id;    }    public void setId(String id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public double getPrice() {        return price;    }    public void setPrice(double price) {        this.price = price;    }    @Override    public int hashCode() {        final int prime = 31;        int result = 1;        result = prime * result + ((id == null) ? 0 : id.hashCode());        result = prime * result + ((name == null) ? 0 : name.hashCode());        long temp;        temp = Double.doubleToLongBits(price);        result = prime * result + (int) (temp ^ (temp >>> 32));        return result;    }    @Override    public boolean equals(Object obj) {        if (this == obj)            return true;        if (obj == null)            return false;        if (getClass() != obj.getClass())            return false;        Book other = (Book) obj;        if (id == null) {            if (other.id != null)                return false;        } else if (!id.equals(other.id))            return false;        if (name == null) {            if (other.name != null)                return false;        } else if (!name.equals(other.name))            return false;        if (Double.doubleToLongBits(price) != Double                .doubleToLongBits(other.price))            return false;        return true;    }    @Override    public String toString() {        return "Book [id=" + id + ", name=" + name + ", price=" + price + "]\n";    }}

三步曲走起：

1、创建解析器工厂
2、新建解析器
3、使用解析器解析文档，获取文档对象

DOM解析

tree

package com.hz.dom;import java.io.IOException;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;import com.hz.Book;/** * DOM解析 *  * @author ztw * * 2016-12-20 */public class DOMParse {    public static List<Book> Parse(String fileName){        List<Book> result = new  ArrayList<Book>();        //1、创建解析器工厂        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();        try {            //2、新建解析器            DocumentBuilder builder = dbf.newDocumentBuilder();            //3、使用解析器解析文档，获取文档对象            Document document = builder.parse(fileName);            //目标是解析book对象            //包含node的容器List<Book>            NodeList nodeList = document.getElementsByTagName("book");            //获取到的长度            int count = nodeList.getLength();            for (int i = 0; i < count; i++) {                Book book = new Book();                //获取到nodeList中的每一个node节点                //强制转换成元素节点                Element elementsNode = (Element) nodeList.item(i);                //获取id属性                String id = elementsNode.getAttribute("id");                book.setId(id);                //获取当前elementsNode的子节点                NodeList childNodesList = elementsNode.getChildNodes();                int size = childNodesList.getLength();                for (int j = 0; j < size; j++) {                    //这里的node有两种节点  文本节点   元素节点                    Node childNode = childNodesList.item(j);                    if(childNode.getNodeType() == Node.ELEMENT_NODE){                        Element childElementsNode = (Element) childNode;                        if("name".equals(childElementsNode.getTagName())){                            String name = childElementsNode.getFirstChild().getNodeValue();                            book.setName(name);                        }else if("price".equals(childElementsNode.getTagName())){                            String priceStr = childElementsNode.getFirstChild().getNodeValue();                            try {                                book.setPrice(Double.valueOf(priceStr));                            } catch (NumberFormatException e) {                                e.printStackTrace();                            }                        }                    }                }                result.add(book);            }        } catch (ParserConfigurationException e) {            e.printStackTrace();        } catch (SAXException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }        return result;    }}

SAX解析

逐行解析

package com.hz.sax;import java.io.File;import java.io.IOException;import javax.xml.parsers.ParserConfigurationException;import javax.xml.parsers.SAXParser;import javax.xml.parsers.SAXParserFactory;import org.xml.sax.SAXException;/** * SAX解析 *  * @author ztw * * 2016-12-20 */public class SaxParse {    public static void parse(String fileName){        //1 创建解析工厂        SAXParserFactory spf = SAXParserFactory.newInstance();        try {            //创建解析器            SAXParser parse = spf.newSAXParser();            parse.parse(new File(fileName), new MyDefaultHandler());        } catch (ParserConfigurationException e) {            e.printStackTrace();        } catch (SAXException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }    }}

package com.hz.sax;import java.util.ArrayList;import java.util.List;import org.xml.sax.Attributes;import org.xml.sax.SAXException;import org.xml.sax.helpers.DefaultHandler;import com.hz.Book;/** * 重写DefaultHandler中的方法 *  * @author ztw * * 2016-12-20 */public class MyDefaultHandler extends DefaultHandler {    private List<Book> bookList;    private Book book;    private String tag;    /**     * 在文档解析开始之前调用     */    @Override    public void startDocument() throws SAXException {        super.startDocument();        bookList = new ArrayList<Book>();    }    /**     * 标签的开始     */    @Override    public void startElement(String uri, String localName, String qName,            Attributes attributes) throws SAXException {        super.startElement(uri, localName, qName, attributes);        tag = qName;        if("book".equals(qName)){            book = new Book();            String id = attributes.getValue("id");            book.setId(id);        }    }    /**     * 对文本的解析     */    @Override    public void characters(char[] ch, int start, int length)            throws SAXException {        super.characters(ch, start, length);        String str = new String(ch, start, length);        if(tag.equals("name")){            book.setName(str);        }else if(tag.equals("price")){            try {                book.setPrice(Double.valueOf(str));            } catch (NumberFormatException e) {                e.printStackTrace();            }        }    }    /**     * 标签的结束     */    @Override    public void endElement(String uri, String localName, String qName)            throws SAXException {        super.endElement(uri, localName, qName);        if(qName.equals("book")){            bookList.add(book);        }        tag = "";    }    /**     * 在文档解析结束之后调用     */    @Override    public void endDocument() throws SAXException {        super.endDocument();        System.out.println(bookList);    }}

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