java

import  java.io.File;  
import  java.io.FileWriter;  
import  java.util.Iterator;  
 
import  org.dom4j.Document;  
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  DOM4JTest   {  
 
      /** */ /**   */   
      /** */ /**   */   
      /** */ /**   */   
      /** */ /**  
     * DOM4J读写XML示例 
     *  
     *  @param  args 
     *  @throws  Exception 
      */   
      public   static   void  main(String[] args)   {  
          try    {  
            XMLWriter writer  =   null ; //  声明写XML的对象   
            SAXReader reader  =   new  SAXReader();  
 
            OutputFormat format  =  OutputFormat.createPrettyPrint();  
            format.setEncoding( " GBK " ); //  设置XML文件的编码格式   
 
            String filePath  =   " d:\\student.xml " ;  
            File file  =   new  File(filePath);  
              if  (file.exists())   {  
                Document document  =  reader.read(file); //  读取XML文件   
                Element root  =  document.getRootElement(); //  得到根节点   
                 boolean  bl  =   false ;  
                  for  (Iterator i  =  root.elementIterator( " 学生 " ); i.hasNext();)   {  
                    Element student  =  (Element) i.next();  
                      if  (student.attributeValue( " sid " ).equals( " 001 " ))   {  
                         //  修改学生sid=001的学生信息   
                        student.selectSingleNode( " 姓名 " ).setText( " 王五 " );  
                        student.selectSingleNode( " 年龄 " ).setText( " 25 " );  
 
                        writer  =   new  XMLWriter( new  FileWriter(filePath), format);  
                        writer.write(document);  
                        writer.close();  
                        bl  =   true ;  
                         break ;  
                    }   
                }   
                  if  (bl)   {  
                     //  添加一个学生信息   
                    Element student  =  root.addElement( " 学生 " );  
                    student.addAttribute( " sid " ,  " 100 " );  
                    Element sid  =  student.addElement( " 编号 " );  
                    sid.setText( " 100 " );  
                    Element name  =  student.addElement( " 姓名 " );  
                    name.setText( " 嘎嘎 " );  
                    Element sex  =  student.addElement( " 性别 " );  
                    sex.setText( " 男 " );  
                    Element age  =  student.addElement( " 年龄 " );  
                    age.setText( " 21 " );  
 
                    writer  =   new  XMLWriter( new  FileWriter(filePath), format);  
                    writer.write(document);  
                    writer.close();  
                }   
             }   else    {  
                 //  新建student.xml文件并新增内容   
                Document _document  =  DocumentHelper.createDocument();  
                Element _root  =  _document.addElement( " 学生信息 " );  
                Element _student  =  _root.addElement( " 学生 " );  
                _student.addAttribute( " sid " ,  " 001 " );  
                Element _id  =  _student.addElement( " 编号 " );  
                _id.setText( " 001 " );  
                Element _name  =  _student.addElement( " 姓名 " );  
                _name.setText( " 灰机 " );  
                Element _age  =  _student.addElement( " 年龄 " );  
                _age.setText( " 18 " );  
 
                writer  =   new  XMLWriter( new  FileWriter(file), format);  
                writer.write(_document);  
                writer.close();  
            }   
            System.out.println( " 操作结束!  " );  
         }   catch  (Exception e)   {  
            e.printStackTrace();  
        }   
 
    }   
}   
执行结果应该是这样：


循环解析节点：
private   void  getAllNodes(String xml)   {  
         try    {  
           Document authtmp  =  DocumentHelper.parseText(xml);  
           List < Element >  list  =  authtmp.selectNodes( " //sms/node " );  
             for  ( int  j  =   0 ; j  <  list.size(); j ++ )   {  
               Element node  =  (Element) list.get(j);  
               nodeByNodes(node);  
           }   
        }   catch  (Exception e)   {  
           e.printStackTrace();  
       }   
   }   
 
     private   void  nodeByNodes(Element node)   {  
         if  (node.element( " node " )  !=   null )   {  
           String id  =  node.attributeValue( " id " );  
           String name  =  node.attributeValue( " name " );  
           System.out.print(id  +   " ------- " );  
           System.out.println(name);  
             for  (Iterator i  =  node.elementIterator( " node " ); i.hasNext();)   {  
               Element newNode  =  (Element) i.next();  
               nodeByNodes(newNode);  
           }   
        }   else    {  
           String id  =  node.attributeValue( " id " );  
           String name  =  node.attributeValue( " name " );  
           System.out.print(id  +   " ------- " );  
           System.out.println(name);  
       }   
   }   
其次DOM4J的解释
一.Document对象相关
1.读取XML文件,获得document对象.
SAXReader reader =   new SAXReader();  
Document   document  =  reader.read( new  File( " input.xml " ));  
2.解析XML形式的文本,得到document对象.
String text  =   " <members></members> ";  
Document document  =  DocumentHelper.parseText(text);  
3.主动创建document对象.
Document document  = DocumentHelper.createDocument();  
Element root  =  document.addElement( " members " ); //  创建根节点  

二.节点相关
1.获取文档的根节点.
Element rootElm  =  document.getRootElement();  
2.取得某节点的单个子节点.
Element memberElm = root.element( " member " ); //  "member"是节点名  
3.取得节点的文字
String text = memberElm.getText();  

也可以用:
String text = root.elementText( " name " );  
这个是取得根节点下的name字节点的文字.
4.取得某节点下名为"member"的所有字节点并进行遍历.
List nodes  =  rootElm.elements( " member ");  
 
for  (Iterator it  =  nodes.iterator(); it.hasNext();)  {  
    Element elm  = (Element) it.next();  
    //  do something  
}   
5.对某节点下的所有子节点进行遍历.
for (Iterator it = root.elementIterator();it.hasNext();) {  
              Element element  =  (Element) it.next();  
              //  do something   
          }   
6.在某节点下添加子节点. 
Element ageElm = newMemberElm.addElement( " age " );  
7.设置节点文字.
ageElm.setText( " 29 " );  
8.删除某节点.
parentElm.remove(childElm); // childElm是待删除的节点,parentElm是其父节点  
9.添加一个CDATA节点.
Element contentElm = infoElm.addElement( " content " );  
contentElm.addCDATA(diary.getContent());  
 
  contentElm.getText(); // 特别说明：获取节点的CDATA值与获取节点的值是一个方法  
  contentElm.clearContent(); //清除节点中的内容，CDATA亦可   

三.属性相关.
1.取得某节点下的某属性
Element root = document.getRootElement();      
Attribute attribute = root.attribute( " size " ); // 属性名name  
2.取得属性的文字
String text = attribute.getText();  

也可以用:
String text2 = root.element( " name " ).attributeValue( " firstname " );  

这个是取得根节点下name字节点的属性firstname的值.
3.遍历某节点的所有属性
Element root = document.getRootElement();      
            for (Iterator it = root.attributeIterator();it.hasNext();) {  
               Attribute attribute  =  (Attribute) it.next();  
               String text = attribute.getText();  
               System.out.println(text);  
           }  
4.设置某节点的属性和文字.
newMemberElm.addAttribute( " name " , " sitinspring " );  
5.设置属性的文字
Attribute attribute = root.attribute( " name " );  
attribute.setText( " sitinspring " );  
6.删除某属性
Attribute attribute = root.attribute( " size " ); // 属性名name   
root.remove(attribute);  
四.将文档写入XML文件.
1.文档中全为英文,不设置编码,直接写入的形式.
XMLWriter writer = new XMLWriter( new FileWriter( " output.xml " ));  
writer.write(document);  
writer.close();  
2.文档中含有中文,设置编码格式写入的形式.
OutputFormat format = OutputFormat.createPrettyPrint();  
format.setEncoding( " GBK " );     // 指定XML编码           
XMLWriter writer = new XMLWriter( new FileWriter( " output.xml " ),format);  
 
writer.write(document);  
writer.close();  
五.字符串与XML的转换
1.将字符串转化为XML 
String text = " <members> <member>sitinspring</member> </members> " ;  
Document document = DocumentHelper.parseText(text);  
2.将文档或节点的XML转化为字符串.
SAXReader reader = new SAXReader();  
Document   document = reader.read( new File( " input.xml " ));              
Element root = document.getRootElement();                  
String docXmlText = document.asXML();  
String rootXmlText = root.asXML();  
Element memberElm = root.element( " member " );  
String memberXmlText = memberElm.asXML(); 使用XPath快速找到节点. 

读取的XML文档示例
<?xml version="1.0" encoding="UTF-8"?> 
<projectDescription> 
  <name>MemberManagement</name> 
  <comment></comment> 
  <projects> 
    <project>PRJ1</project> 
    <project>PRJ2</project> 
    <project>PRJ3</project> 
    <project>PRJ4</project> 
  </projects> 
  <buildSpec> 
    <buildCommand> 
      <name>org.eclipse.jdt.core.javabuilder</name> 
      <arguments> 
      </arguments> 
    </buildCommand> 
  </buildSpec> 
  <natures> 
    <nature>org.eclipse.jdt.core.javanature</nature> 
  </natures> 
</projectDescription> 

使用XPath快速找到节点project.
public static void main(String[] args){  
   SAXReader reader = new SAXReader();  
     
   try{  
     Document  doc = reader.read(new File("sample.xml"));  
       
     List projects=doc.selectNodes("/projectDescription/projects/project");  
       
     Iterator it=projects.iterator();  
       
     while(it.hasNext()){  
       Element elm=(Element)it.next();         
       System.out.println(elm.getText());  
     }  
       
   }  
   catch(Exception ex){  
      ex.printStackTrace();  
   }  
}