import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.InputStream;import java.io.OutputStream;import java.io.UnsupportedEncodingException;import java.util.ArrayList;import java.util.List;import org.dom4j.Document;import org.dom4j.DocumentException;import org.dom4j.DocumentHelper;import org.dom4j.Element;import org.dom4j.io.OutputFormat;import org.dom4j.io.SAXReader;import org.dom4j.io.XMLWriter;public class BookUtis {		public List
     
       xmlToBook(InputStream is) throws Exception{		//封装了对xml的解析		SAXReader read=new SAXReader();		//做文件,解析器读取数据InputStream。从网络端收取数据或者从文件中读取数据		Document doc=read.read(is);		//根元素		Element root=doc.getRootElement();		List
      
        booklist=new ArrayList
       
        ();						 List
        
          bookElements=root.elements("book");//这个文件万一下面有多个子元素的话，只拿其中book		 for(Element e:bookElements){			Book book=new Book();			//明确book下只有name单个元素			//                 book元素下获取name返回Element类型的list，只有一个元素取get(0)获取第一行，整体扩起来是一个单个元素，获取文本，tostring						String name=((Element)(e.elements("name").get(0))).getData().toString();						double price=Double.parseDouble(((Element)(e.elements("price").get(0))).getData().toString());						book.setName(name);			book.setPrice(price);			booklist.add(book);		 }				return booklist;	}		public List
         
           xmlToBook(String xmlFileName) throws Exception{		InputStream is=new FileInputStream(xmlFileName);		List
          
            list=xmlToBook(is); return list; } public void bookToXML(List
           
             booklist,OutputStream os) throws Exception{ Document doc=DocumentHelper.createDocument(); Element root=doc.addElement("books"); for(Book book:booklist){ Element bookElement=root.addElement("book"); bookElement.addElement("name").setText(book.getName()); bookElement.addElement("price").setText(String.valueOf(book.getPrice())); } XMLWriter write=new XMLWriter(os,OutputFormat.createCompactFormat()); write.write(doc); write.close(); }}