java中的XML

一：读取XML

1. DOM解析
2. SAX解析
3. DOM4J解析
4. JDOM解析

1.DOM解析：是把xml文件全部读到内存中。然后再进行解析。

<?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>

books.xml文件如上图

解析如下：

package com.imooc.domtest.test;

import java.io.IOException;

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.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class DOMTest {

    public static void main(String[] args) {
        //创建一个DocumentBuilderFactory的对象
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        //创建一个DocumentBuilder的对象
        try {
            //创建DocumentBuilder对象
            DocumentBuilder db = dbf.newDocumentBuilder();
            //通过DocumentBuilder对象的parser方法加载books.xml文件到当前项目下
            Document document = db.parse("books.xml");
            //获取所有book节点的集合
            NodeList bookList = document.getElementsByTagName("book");
            //通过nodelist的getLength()方法可以获取bookList的长度
            System.out.println("一共有" + bookList.getLength() + "本书");
            //遍历每一个book节点
            for (int i = 0; i < bookList.getLength(); i++) {
                System.out.println("=================下面开始遍历第" + (i + 1) + "本书的内容=================");
                //通过 item(i)方法 获取一个book节点，nodelist的索引值从0开始
                Node book = bookList.item(i);
//                获取book节点的所有属性集合
                NamedNodeMap attrs = book.getAttributes();
                System.out.println("第 " + (i + 1) + "本书共有" + attrs.getLength() + "个属性");
//                遍历book的属性
                for (int j = 0; j < attrs.getLength(); j++) {
                    //通过item(index)方法获取book节点的某一个属性
                    Node attr = attrs.item(j);
                    //获取属性名
                    System.out.print("属性名：" + attr.getNodeName());
                    //获取属性值
                    System.out.println("--属性值" + attr.getNodeValue());
                }
//                //前提：已经知道book节点有且只能有1个id属性
//                //将book节点进行强制类型转换，转换成Element类型
//                Element book = (Element) bookList.item(i);
//                //通过getAttribute("id")方法获取属性值
//                String attrValue = book.getAttribute("id");
//                System.out.println("id属性的属性值为" + attrValue);
                //解析book节点的子节点
                NodeList childNodes = book.getChildNodes();
                //遍历childNodes获取每个节点的节点名和节点值
                System.out.println("第" + (i+1) + "本书共有" + 
                childNodes.getLength() + "个子节点");
                for (int k = 0; k < childNodes.getLength(); k++) {
                    //区分出text类型的node以及element类型的node
                    if (childNodes.item(k).getNodeType() == Node.ELEMENT_NODE) {
                        //获取了element类型节点的节点名
                        System.out.print("第" + (k + 1) + "个节点的节点名：" 
                        + childNodes.item(k).getNodeName());
//                        获取了element类型节点的节点值
                        System.out.println("--节点值是：" + childNodes.item(k).getFirstChild().getNodeValue());
//                        System.out.println("--节点值是：" + childNodes.item(k).getTextContent());
                    }
                }
                System.out.println("======================结束遍历第" + (i + 1) + "本书的内容=================");
            }
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        }  catch (SAXException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        
    }
}

 2.SAX解析，handle像是驱动式进行读取XML文件

进行测试类

package com.imooc.test;

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 {

    /**
     * @param args
     */
    public static void main(String[] args) {
        //获取一个SAXParserFactory的实例
        SAXParserFactory factory = SAXParserFactory.newInstance();
        //通过factory获取SAXParser实例
        try {
            SAXParser parser = factory.newSAXParser();
            //获取SAXParserHandler实例
            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();
        }
    }

}

//进行SAX解析的工具类
package com.imooc.handler;

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元素下属性的名称，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元素下属性的名称以及个数，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 localName, String qName)
            throws SAXException {
        //调用DefaultHandler类的endElement方法
        super.endElement(uri, localName, 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, start, length);
        if (!value.trim().equals("")) {
            System.out.println("节点值是：" + value);
        }
    }
}

//book的实体类
package com.imooc.entity;

public class Book {
    private String id;
    private String name;
    private String author;
    private String year;
    private String price;
    private String language;
    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 String getAuthor() {
        return author;
    }
    public void setAuthor(String author) {
        this.author = author;
    }
    public String getYear() {
        return year;
    }
    public void setYear(String year) {
        this.year = year;
    }
    public String getPrice() {
        return price;
    }
    public void setPrice(String price) {
        this.price = price;
    }
    public String getLanguage() {
        return language;
    }
    public void setLanguage(String language) {
        this.language = language;
    }
    
    
}

 3.JDOM解析XML

 maven中的depend的路劲

 <!-- 解析XML文件jdom2.0系列 -->
       <dependency>
         <groupId>org.jdom</groupId>
         <artifactId>jdom2</artifactId>
         <version>2.0.6</version>
     </dependency>

 测试JDOM的test

package com.imooc.jdomtest;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import org.jdom2.Attribute;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;

import com.imooc.entity.Book;


public class JDOMTest {
    private static ArrayList<Book> booksList = new ArrayList<Book>();
    /**
     * @param args
     */
    public static void main(String[] args) {
        // 进行对books.xml文件的JDOM解析
        // 准备工作
        // 1.创建一个SAXBuilder的对象
        SAXBuilder saxBuilder = new SAXBuilder();
        InputStream in;
        try {
            // 2.创建一个输入流，将xml文件加载到输入流中
            in = new FileInputStream("src/res/books.xml");
            InputStreamReader isr = new InputStreamReader(in, "UTF-8");
            // 3.通过saxBuilder的build方法，将输入流加载到saxBuilder中
            Document document = saxBuilder.build(isr);
            // 4.通过document对象获取xml文件的根节点
            Element rootElement = document.getRootElement();
            // 5.获取根节点下的子节点的List集合
            List<Element> bookList = rootElement.getChildren();
            // 继续进行解析
            for (Element book : bookList) {
                Book bookEntity = new Book();
                System.out.println("======开始解析第" + (bookList.indexOf(book) + 1)
                        + "书======");
                // 解析book的属性集合
                List<Attribute> attrList = book.getAttributes();
                // //知道节点下属性名称时，获取节点值
                // book.getAttributeValue("id");
                // 遍历attrList(针对不清楚book节点下属性的名字及数量)
                for (Attribute attr : attrList) {
                    // 获取属性名
                    String attrName = attr.getName();
                    // 获取属性值
                    String attrValue = attr.getValue();
                    System.out.println("属性名：" + attrName + "----属性值："
                            + attrValue);
                    if (attrName.equals("id")) {
                        bookEntity.setId(attrValue);
                    }
                }
                // 对book节点的子节点的节点名以及节点值的遍历
                List<Element> bookChilds = book.getChildren();
                for (Element child : bookChilds) {
                    System.out.println("节点名：" + child.getName() + "----节点值："
                            + child.getValue());
                    if (child.getName().equals("name")) {
                        bookEntity.setName(child.getValue());
                    }
                    else if (child.getName().equals("author")) {
                        bookEntity.setAuthor(child.getValue());
                    }
                    else if (child.getName().equals("year")) {
                        bookEntity.setYear(child.getValue());
                    }
                    else if (child.getName().equals("price")) {
                        bookEntity.setPrice(child.getValue());
                    }
                    else if (child.getName().equals("language")) {
                        bookEntity.setLanguage(child.getValue());
                    }
                }
                System.out.println("======结束解析第" + (bookList.indexOf(book) + 1)
                        + "书======");
                booksList.add(bookEntity);
                bookEntity = null;
                System.out.println(booksList.size());
                System.out.println(booksList.get(0).getId());
                System.out.println(booksList.get(0).getName());
                
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (JDOMException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

 4.DOM4J解析方式：

maven中depend

<!-- 解析XML文件dom4j -->
      <dependency>
        <groupId>dom4j</groupId>
        <artifactId>dom4j</artifactId>
        <version>1.6.1</version>
    </dependency>

DOM4J测试类

package com.imooc.dom4jtest;

import java.io.File;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import com.imooc.entity.Book;

public class DOM4JTest {
    private static ArrayList<Book> bookList = new ArrayList<Book>();
    /**
     * @param args
     */
    public static void main(String[] args) {
        // 解析books.xml文件
        // 创建SAXReader的对象reader
        SAXReader reader = new SAXReader();
        try {
            // 通过reader对象的read方法加载books.xml文件,获取docuemnt对象。
            Document document = reader.read(new File("src/res/books.xml"));
            // 通过document对象获取根节点bookstore
            Element bookStore = document.getRootElement();
            // 通过element对象的elementIterator方法获取迭代器
            Iterator it = bookStore.elementIterator();
            // 遍历迭代器，获取根节点中的信息（书籍）
            while (it.hasNext()) {
                System.out.println("=====开始遍历某一本书=====");
                Element book = (Element) it.next();
                // 获取book的属性名以及 属性值
                List<Attribute> bookAttrs = book.attributes();
                for (Attribute attr : bookAttrs) {
                    System.out.println("属性名：" + attr.getName() + "--属性值："
                            + attr.getValue());
                }
                Iterator itt = book.elementIterator();
                while (itt.hasNext()) {
                    Element bookChild = (Element) itt.next();
                    System.out.println("节点名：" + bookChild.getName() + "--节点值：" + bookChild.getStringValue());
                }
                System.out.println("=====结束遍历某一本书=====");
            }
        } catch (DocumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

}

 四种解析方法的对比

利用junit进行测试编码测试

package com.parser.test;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.dom4j.DocumentException;
import org.dom4j.io.SAXReader;
import org.jdom2.Attribute;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;
import org.junit.Test;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import com.imooc.entity.Book;
import com.imooc.handler.SAXParserHandler;

public class ParseTest {


    public void domXmlParser() {
        ArrayList<Book> bookLists = new ArrayList<Book>();
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        try {
            DocumentBuilder db = dbf.newDocumentBuilder();
            Document document = db.parse("books.xml");
            NodeList bookList = document.getElementsByTagName("book");
            for (int i = 0; i < bookList.getLength(); i++) {
                Node book = bookList.item(i);
                Book bookEntity = new Book();
                NamedNodeMap attrs = book.getAttributes();
                for (int j = 0; j < attrs.getLength(); j++) {
                    Node attr = attrs.item(j);
                    if (attr.getNodeName().equals("id")) {
                        bookEntity.setId(attr.getNodeValue());
                    }
                }
                NodeList childNodes = book.getChildNodes();
                for (int k = 0; k < childNodes.getLength(); k++) {
                    if (childNodes.item(k).getNodeType() == Node.ELEMENT_NODE) {
                        String name = childNodes.item(k).getNodeName();
                        String value = childNodes.item(k).getFirstChild().getNodeValue();
                        if (name.equals("name")) {
                            bookEntity.setName(value);
                        }
                        else if (name.equals("author")) {
                            bookEntity.setAuthor(value);
                        }
                        else if (name.equals("year")) {
                            bookEntity.setYear(value);
                        }
                        else if (name.equals("price")) {
                            bookEntity.setPrice(value);
                        }
                        else if (name.equals("language")) {
                            bookEntity.setLanguage(value);
                        }
                    }
                }
                bookLists.add(bookEntity);
                bookEntity = null;
            }
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    public void saxXmlParser(){
        SAXParserFactory factory = SAXParserFactory.newInstance();
        try {
            SAXParser parser = factory.newSAXParser();
            SAXParserHandler handler = new SAXParserHandler();
            parser.parse("books.xml", handler);
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    public void jdomXmlParser() {
        ArrayList<Book> booksList = new ArrayList<Book>();
        SAXBuilder saxBuilder = new SAXBuilder();
        InputStream in;
        try {
            in = new FileInputStream("books.xml");
            InputStreamReader isr = new InputStreamReader(in, "UTF-8");
            org.jdom2.Document document = saxBuilder.build(isr);
            org.jdom2.Element rootElement = document.getRootElement();
            List<org.jdom2.Element> bookList = rootElement.getChildren();
            for (org.jdom2.Element book : bookList) {
                Book bookEntity = new Book();
                List<Attribute> attrList = book.getAttributes();
                for (Attribute attr : attrList) {
                    String attrName = attr.getName();
                    String attrValue = attr.getValue();
                    if (attrName.equals("id")) {
                        bookEntity.setId(attrValue);
                    }
                }
                List<org.jdom2.Element> bookChilds = book.getChildren();
                for (org.jdom2.Element child : bookChilds) {
                    if (child.getName().equals("name")) {
                        bookEntity.setName(child.getValue());
                    }
                    else if (child.getName().equals("author")) {
                        bookEntity.setAuthor(child.getValue());
                    }
                    else if (child.getName().equals("year")) {
                        bookEntity.setYear(child.getValue());
                    }
                    else if (child.getName().equals("price")) {
                        bookEntity.setPrice(child.getValue());
                    }
                    else if (child.getName().equals("language")) {
                        bookEntity.setLanguage(child.getValue());
                    }
                }
                booksList.add(bookEntity);
                bookEntity = null;
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (JDOMException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
    
    public void dom4jXmlParser(){
        ArrayList<Book> booksList = new ArrayList<Book>();
        SAXReader reader = new SAXReader();
        try {
            org.dom4j.Document document = reader.read(new File("books.xml"));
            org.dom4j.Element bookStore = document.getRootElement();
            List<org.dom4j.Element> bookEles = bookStore.elements();
            for (org.dom4j.Element book : bookEles) {
                Book bookEntity = new Book();
                List<org.dom4j.Attribute> bookAttrs = book.attributes();
                for (org.dom4j.Attribute attr : bookAttrs) {
                    if (attr.getName().equals("id")) {
                        bookEntity.setId(attr.getValue());
                    }
                }
                List<org.dom4j.Element> bookss = book.elements();
                for (org.dom4j.Element bookChild : bookss) {
                    String name = bookChild.getName();
                    String value = bookChild.getStringValue();
                    if (name.equals("name")) {
                        bookEntity.setName(value);
                    }
                    else if (name.equals("author")) {
                        bookEntity.setAuthor(value);
                    }
                    else if (name.equals("year")) {
                        bookEntity.setYear(value);
                    }
                    else if (name.equals("price")) {
                        bookEntity.setPrice(value);
                    }
                    else if (name.equals("language")) {
                        bookEntity.setLanguage(value);
                    }
                }
                booksList.add(bookEntity);
                bookEntity = null;
            }
        } catch (DocumentException e) {
            e.printStackTrace();
        }
    }

    @Test
    public void testPerformance() throws Exception{
        System.out.println("性能测试:");
        //测试DOM的性能:
        long start = System.currentTimeMillis();
        domXmlParser();
        System.out.println("DOM:"+ (System.currentTimeMillis() - start) );
        //测试SAX的性能:
        start = System.currentTimeMillis();
        saxXmlParser();
        System.out.println("SAX:"+ (System.currentTimeMillis() - start) );
        //测试JDOM的性能:
        start = System.currentTimeMillis();
        jdomXmlParser();
        System.out.println("JDOM:"+ (System.currentTimeMillis() - start) );
        //测试DOM4J的性能:
        start = System.currentTimeMillis();
        dom4jXmlParser();
        System.out.println("DOM4J:"+ (System.currentTimeMillis() - start) );
    
    }
}

性能输入：

dom:67

sax:6

jdom:86

dom4j:72

在性能方面当然是sax解析速度较快。但是在java中常用的解析方式是dom4j。例如hibernate中就是用dom4j来进行解析配置文件。

在通用解析上用Dom方式进行解析的比较多。还可以解析一个dom对象的html文件等。

二：写XML

java 中直接写入xml文件

1，DOM方式写入XML 文件

package com.imooc.domtest.test;

import java.io.File;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class CreateXML {

    public DocumentBuilder getDocumentBuilder(){
        // 创建一个DocumentBuilderFactory的对象
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        // 创建DocumentBuilder对象
        DocumentBuilder db =null;
        try {
            db = dbf.newDocumentBuilder();
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        }
        return db;
    }
    
    /**
     * 生成xml
     */
    public void createXML(){
        DocumentBuilder db = getDocumentBuilder();
        Document document = db.newDocument();
        document.setXmlStandalone(true);
        Element bookstore = document.createElement("bookStore");
        //向bookstore根节点中添加子节点book
        Element book = document.createElement("book");
        Element name = document.createElement("name");
//        name.setNodeValue("小王子");
        name.setTextContent("小王子");
        
        book.appendChild(name);
        book.setAttribute("id", "1");
        //将book节点添加到bookstore根节点中
        bookstore.appendChild(book);
        //将bookstore节点（已经包含了book）添加到dom树中
        document.appendChild(bookstore);
        //创建TransformerFactory对象
        TransformerFactory tff = TransformerFactory.newInstance();
        try {
            //创建Transformer对象
            Transformer tf = tff.newTransformer();
            tf.setOutputProperty(OutputKeys.INDENT, "yes");
            tf.transform(new DOMSource(document),new StreamResult(new File("books1.xml")));
        } catch (TransformerConfigurationException e) {
            e.printStackTrace();
        } catch (TransformerException e) {
            e.printStackTrace();
        }
    }
    
    public static void main(String[] args) {
        CreateXML creatXml = new CreateXML();
        creatXml.createXML();
    }

}

2，SAX方式写入xml文件

在sax方式写入xml文件。

package com.imooc.test;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;

import javax.xml.transform.Result;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamResult;

import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;

import com.imooc.entity.Book;

public class SAXTestCreate {

    public static  ArrayList<Book> bookList;

    static {
        Book b1 = new Book();
        b1.setId("1");
        b1.setName("冰与火之歌");
        b1.setAuthor("乔治马丁");
        b1.setYear("2014");
        b1.setPrice("89");
        Book b2 = new Book();
        b2.setId("2");
        b2.setName("安徒生童话");
        b2.setAuthor("乔治马丁");
        b2.setYear("2004");
        b2.setPrice("77");
        b2.setLanguage("English");
        bookList.add(b1);
        bookList.add(b2);


    }


    public void createXML() {
        
        // 生成xml
        // 1.创建一个TransformerFactory类的对象
        SAXTransformerFactory tff = (SAXTransformerFactory) SAXTransformerFactory
                .newInstance();
        try {
            // 2.通过SAXTransformerFactory对象创建一个TransformerHandler对象
            TransformerHandler handler = tff.newTransformerHandler();
            // 3.通过handler对象创建一个Transformer对象
//            Transformer tr = handler.getTransformer();
//            // 4.通过Transformer对象对生成的xml文件进行设置
//            // 设置xml的编码
//            tr.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
//            // 设置xml的“是否换行”
//            tr.setOutputProperty(OutputKeys.INDENT, "yes");
            // 5.创建一个Result对象
            File f = new File("src/res/newbooks.xml");
            if (!f.exists()) {
                f.createNewFile();
            }
            // 6.创建Result对象，并且使其与handler关联
            Result result = new StreamResult(new FileOutputStream(f));
            handler.setResult(result);
            // 7.利用handler对象进行xml文件内容的编写O
            // 打开document
            handler.startDocument();
            AttributesImpl attr = new AttributesImpl();
            handler.startElement("", "", "bookstore", attr);
            
            for (Book book : bookList) {
                attr.clear();
                attr.addAttribute("", "", "id", "", book.getId());
                handler.startElement("", "", "book", attr);
                // 创建name节点
                if (book.getName() != null && !book.getName().trim().equals("")) {
                    attr.clear();
                    handler.startElement("", "", "name", attr);
                    handler.characters(book.getName().toCharArray(), 0, book
                            .getName().length());
                    handler.endElement("", "", "name");
                }
                // 创建year节点
                if (book.getYear() != null && !book.getYear().trim().equals("")) {
                    attr.clear();
                    handler.startElement("", "", "year", attr);
                    handler.characters(book.getYear().toCharArray(), 0, book
                            .getYear().length());
                    handler.endElement("", "", "year");
                }
                // 创建author节点
                if (book.getAuthor() != null && !book.getAuthor().trim().equals("")) {
                    attr.clear();
                    handler.startElement("", "", "author", attr);
                    handler.characters(book.getAuthor().toCharArray(), 0, book
                            .getAuthor().length());
                    handler.endElement("", "", "author");
                }
                // 创建price节点
                if (book.getPrice() != null && !book.getPrice().trim().equals("")) {
                    attr.clear();
                    handler.startElement("", "", "price", attr);
                    handler.characters(book.getPrice().toCharArray(), 0, book
                            .getPrice().length());
                    handler.endElement("", "", "price");
                }
                // 创建language节点
                if (book.getLanguage() != null && !book.getLanguage().trim().equals("")) {
                    attr.clear();
                    handler.startElement("", "", "language", attr);
                    handler.characters(book.getLanguage().toCharArray(), 0, book
                            .getLanguage().length());
                    handler.endElement("", "", "language");
                }
                handler.endElement("", "", "book");
            }
            handler.endElement("", "", "bookstore");
            // 关闭document
            handler.endDocument();

        } catch (TransformerConfigurationException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        }
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        SAXTestCreate test = new SAXTestCreate();
        test.createXML();
    }

}

book.class为上一章解析xml的book类

3.DOM4J 生成xml文件

package com.imooc.dom4jtest;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;

public class DOM4JTest {
    private void createXML(){
        //1.创建document对象，代表整个xml文档
        Document document = DocumentHelper.createDocument();
        //2.创建根节点rss
        Element rss = document.addElement("rss");
        //3.向rss节点中添加version属性
        rss.addAttribute("version", "2.0");
        //4.生成子节点及节点内容
        Element channel = rss.addElement("channel");
        Element title = channel.addElement("title");
        title.setText("<![CDATA[上海移动互联网产业促进中心正式揭牌 ]]>");
        //5.设置生成xml的格式
        OutputFormat format = OutputFormat.createPrettyPrint();
        format.setEncoding("GBK");
        //6.生成xml文件
        File file = new File("rssnews.xml");
        XMLWriter writer;
        try {
            writer = new XMLWriter(new FileOutputStream(file), format);
            //设置是否转义，默认值是true，代表转义
            writer.setEscapeText(false);
            writer.write(document);
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        new DOM4JTest().createXML();
    }

}

4.JOM生成xml文件

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.output.Format;
import org.jdom2.output.XMLOutputter;


public class JDOMTestCreate {

    private void createXML() {
        //1.生成一个根节点
        Element rss = new Element("rss");
        //2.为节点添加属性
        rss.setAttribute("version", "2.0");
        //3.生成一个document对象
        Document document = new Document(rss);
        
        Element channel = new Element("channel");
        rss.addContent(channel);
        //Element title = new Element("title");
        //title.setText("<![CDATA[上海移动互联网产业促进中心正式揭牌 ]]>");

　　　　　　Element title = new Element("title");

　　　　　　CDATA cdata = new CDATA("上海移动互联网产业促进中心正式揭牌");

　　　　　　title.setContent(cdata);

        channel.addContent(title);
        
        Format format = Format.getCompactFormat();
        format.setIndent("");
        format.setEncoding("GBK");
        
        //4.创建XMLOutputter的对象
        XMLOutputter outputer = new XMLOutputter(format);
        try {
            //5.利用outputer将document对象转换成xml文档
            outputer.output(document, new FileOutputStream(new File("rssnews.xml")));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    public static void main(String[] args) {
        JDOMTestCreate creater = new JDOMTestCreate();
        creater.createXML();
    }

}

生成xml文件的速度测试：DOM生成可以进行频繁的修改节点信息。而sax生成则不能在生成节点信息之后再进行修改等操作。DOM4j和JDOM方式则基于java的基础api的方式进行了优化。

测试代码：

package com.create.test;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamResult;

import org.dom4j.DocumentHelper;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;
import org.jdom2.output.Format;
import org.jdom2.output.XMLOutputter;
import org.junit.Test;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;


public class CreateTest {

    /**
     * DOM方式生成xml文档
     */
    private void DOMCreateXML() {
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = null;
        try {
            db = dbf.newDocumentBuilder();
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        }
        Document document = db.newDocument();
        document.setXmlStandalone(true);
        Element bookstore = document.createElement("bookStore");
        Element book = document.createElement("book");
        Element name = document.createElement("name");
        name.setTextContent("小王子");
        book.appendChild(name);
        book.setAttribute("id", "1");
        bookstore.appendChild(book);
        document.appendChild(bookstore);
        TransformerFactory tff = TransformerFactory.newInstance();
        try {
            Transformer tf = tff.newTransformer();
            tf.setOutputProperty(OutputKeys.INDENT, "yes");
            tf.transform(new DOMSource(document), new StreamResult(new File(
                    "books1.xml")));
        } catch (TransformerConfigurationException e) {
            e.printStackTrace();
        } catch (TransformerException e) {
            e.printStackTrace();
        }
    }
    
    /**
     * SAX方式生成xml文档
     */
    public void SAXCreateXML() {
        SAXTransformerFactory tff = (SAXTransformerFactory) SAXTransformerFactory
                .newInstance();
        try {
            TransformerHandler handler = tff.newTransformerHandler();
            Transformer tr = handler.getTransformer();
            tr.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
            tr.setOutputProperty(OutputKeys.INDENT, "yes");
            File f = new File("books2.xml");
            if (!f.exists()) {
                f.createNewFile();
            }
            Result result = new StreamResult(new FileOutputStream(f));
            handler.setResult(result);
            handler.startDocument();
            AttributesImpl attr = new AttributesImpl();
            handler.startElement("", "", "bookstore", attr);
            attr.clear();
            attr.addAttribute("", "", "id", "", "1");
            handler.startElement("", "", "book", attr);
            attr.clear();
            handler.startElement("", "", "name", attr);
            handler.characters("小王子".toCharArray(), 0, "小王子".length());
            handler.endElement("", "", "name");
        
            handler.endElement("", "", "book");
            handler.endElement("", "", "bookstore");
            handler.endDocument();

        } catch (TransformerConfigurationException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        }
    }
    
    /**
     * JDOM方式生成xml文档
     */
    private void JDOMCreateXML() {
        org.jdom2.Element bookstore = new org.jdom2.Element("bookstore");
        org.jdom2.Document document = new org.jdom2.Document(bookstore);
        
        org.jdom2.Element book = new org.jdom2.Element("book");
        book.setAttribute("id", "1");
        org.jdom2.Element name = new org.jdom2.Element("name");
        name.setText("小王子");
        book.addContent(name);
        bookstore.addContent(book);
        Format format = Format.getCompactFormat();
        format.setIndent("");
        format.setEncoding("UTF-8");
        XMLOutputter outputer = new XMLOutputter(format);
        try {
            outputer.output(document, new FileOutputStream(new File("books3.xml")));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    /**
     * DOM4J方式生成xml文档
     */
    private void DOM4JCreateXML(){
        org.dom4j.Document document = DocumentHelper.createDocument();
        org.dom4j.Element bookstore = document.addElement("bookstore");
        org.dom4j.Element book = bookstore.addElement("book");
        book.addAttribute("id", "1");
        org.dom4j.Element name = book.addElement("name");
        name.setText("小王子");
        OutputFormat format = OutputFormat.createPrettyPrint();
        format.setEncoding("UTF-8");
        File file = new File("books4.xml");
        XMLWriter writer;
        try {
            writer = new XMLWriter(new FileOutputStream(file), format);
            writer.setEscapeText(false);
            writer.write(document);
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Test
    public void testPerformance() throws Exception{
        System.out.println("性能测试:");
        //测试DOM的性能:
        long start = System.currentTimeMillis();
        DOMCreateXML();
        System.out.println("DOM:"+ (System.currentTimeMillis() - start));
        //测试SAX的性能:
        start = System.currentTimeMillis();
        SAXCreateXML();
        System.out.println("SAX:"+ (System.currentTimeMillis() - start) );
        //测试JDOM的性能:
        start = System.currentTimeMillis();
        JDOMCreateXML();
        System.out.println("JDOM:"+ (System.currentTimeMillis() - start) );
        //测试DOM4J的性能:
        start = System.currentTimeMillis();
        DOM4JCreateXML();
        System.out.println("DOM4J:"+ (System.currentTimeMillis() - start) );
    }
}

性能测试：

DOM：418

SAX：3

JDOM：158

DOM4J：59

在项目中常用的是DOM4J进行解析XMl和生成XML文件。