实例分析jdom和dom4j的使用和区别

　　对于xml的解析和生成，我们在实际应用中用的比较多的是JDOM和DOM4J，下面通过例子来分析两者的区别（在这里我就不详细讲解怎么具体解析xml，如果对于xml的解析看不懂的可以先去看下我之前关于dom跟sax解析xml的随笔http://www.cnblogs.com/zhi-hao/p/3985720.html，其实理解了解析xml的原理，要想学习jdom跟dom4j就比较简单了，jdom跟dom4j只是基于底层api的更高级的封装，而dom和sax是解析xml的底层接口），我们在使用jdom和dom4j时要导入相应的包，这些包可以到jdom和dom4j的官网去下载。

首先通过jdom来生成xml

 

 1 package xmlTest;
 2 /**
 3  * @author CIACs
 4  */
 5 import java.io.FileOutputStream;
 6 
 7 import org.jdom.Document;
 8 import org.jdom.Element;
 9 import org.jdom.output.Format;
10 import org.jdom.output.XMLOutputter;
11 
12 public class Jdom {
13 
14     public static void main(String[] args) throws Exception{
15         Document doc = new Document();
16         Element root = new Element("root");
17         doc.addContent(root);
18     
19         Element name = new Element("name");
20         root.addContent(name);
21         root.setAttribute("author","CIACs").setAttribute("url", "http://www.cnblogs.com/zhi-hao/");
22         name.addContent("CIACs");
23         
24         XMLOutputter out = new XMLOutputter();
25         Format format = Format.getPrettyFormat();
26         format.setIndent("   ");
27         out.setFormat(format);
28         out.output(doc,new FileOutputStream("jdom.xml"));
29         
30     }
31     
32 }

 

生成的xml

1 <?xml version="1.0" encoding="UTF-8"?>
2 <root author="CIACs" url="http://www.cnblogs.com/zhi-hao/">
3    <name>CIACs</name>
4 </root>

这里生成的xml比较简单，这是为了容易理解，简单的理解了，复杂的其实也就会了。

 

接下来通过jdom对xml进行解析

 1 package xmlTest;
 2 /**
 3  * @author CIACs
 4  */
 5 import java.io.File;
 6 import java.io.FileOutputStream;
 7 import java.util.List;
 8 
 9 import org.jdom.Attribute;
10 import org.jdom.Document;
11 import org.jdom.Element;
12 import org.jdom.input.SAXBuilder;
13 import org.jdom.output.XMLOutputter;
14 
15 public class Jdom2 {
16 
17     public static void main(String[] args) throws Exception {
18         //通过SAXBuilder解析xml
19         SAXBuilder builder = new SAXBuilder();
20         
21         Document doc = builder.build(new File("jdom.xml"));
22         
23         Element root = doc.getRootElement();
24         
25         System.out.println(root.getName());
26         
27         String name = root.getChild("name").getText();
28         
29         System.out.println("name: "+name);
30         
31         List attrs = root.getAttributes();
32         
33         for(int i = 0; i < attrs.size();i++)
34         {
35             String attrName;
36             String attrValue;
37             Attribute attr = (Attribute)attrs.get(i);
38             attrName = attr.getName();
39             attrValue = attr.getValue();
40             System.out.println(attrName+":"+attrValue);
41 
42         }
43         //删除属性url，并保存到jdom2.xml
44         root.removeAttribute("url");
45         
46         XMLOutputter out = new XMLOutputter();
47         out.output(doc, new FileOutputStream("jdom2.xml"));
48 
49         
50     }
51 }

控制台窗口输出的结果：

写入jdom2.xml的内容

下面是用dom4j来操作xml

  1 package xmlTest;
  2 /**
  3  * @author CIACs
  4  */
  5 import java.io.File;
  6 import java.io.FileOutputStream;
  7 import java.util.List;
  8 
  9 import javax.xml.parsers.DocumentBuilder;
 10 import javax.xml.parsers.DocumentBuilderFactory;
 11 
 12 import org.dom4j.Attribute;
 13 import org.dom4j.Document;
 14 import org.dom4j.DocumentFactory;
 15 import org.dom4j.DocumentHelper;
 16 import org.dom4j.Element;
 17 import org.dom4j.io.DOMReader;
 18 import org.dom4j.io.OutputFormat;
 19 import org.dom4j.io.SAXReader;
 20 import org.dom4j.io.XMLWriter;
 21 
 22 public class Dom4j {
 23     public static void main(String[] args) throws Exception {
 24         //创建文档跟节点
 25         Document doc =  DocumentFactory.getInstance().createDocument();
 26         Element root = DocumentHelper.createElement("root");
 27         doc.setRootElement(root);
 28         
 29         Element name = DocumentHelper.createElement("name");
 30         name.setText("CIACs");
 31         name.addAttribute("age", "22");
 32         root.add(name);
 33         root.addElement("address").addAttribute("province", "guangdong").addElement("country").setText("guangzhou");
 34         
 35         //生成的xml输出到命令行窗口
 36         OutputFormat format = new OutputFormat("    ",true);
 37         XMLWriter writer = new XMLWriter(format);
 38         writer.write(doc);
 39     
 40         XMLWriter writer2 = new XMLWriter(new FileOutputStream(new File("dom4j.xml")),format);
 41         //生成的xml写到内存中
 42         writer2.write(doc);
 43         
 44         
 45         System.out.println("-----------通过SAXReader来解析xml文档-----------");
 46         SAXReader reader = new SAXReader();
 47         Document doc2 = reader.read(new File("dom4j.xml"));
 48         Element root2 = doc2.getRootElement();
 49 
 50         parse(root2);
 51         
 52         System.out.println("---------通过DOMReader来解析xml文档-------------");
 53         
 54         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
 55         DocumentBuilder db = dbf.newDocumentBuilder();
 56         //当一个程序中引用同名不同包的两个Document,其中一个必须要加包名加以区别
 57         org.w3c.dom.Document doc3 = db.parse(new File("dom4j.xml"));
 58         DOMReader domReader = new DOMReader();
 59         //将JAXP的document转换为dom4j的document
 60         Document doc4 = domReader.read(doc3);
 61         //获得根元素的名称
 62         String rootName = doc4.getRootElement().getName();
 63         System.out.println(rootName);
 64         
 65     }
 66     
 67     public static void parse(Element element)
 68     {
 69         List<Attribute> list = element.attributes();
 70         if(!list.isEmpty())
 71         {
 72         for(Attribute attr:list)
 73         {
 74             System.out.println("属性："+attr.getName()+"="+attr.getText());
 75         }
 76         }
 77         List<Element> list2 = element.elements();
 78         for(int i=0;i<list2.size();i++)
 79         {
 80             
 81             
 82             
 83             if(list2.get(i).elements().size()>=1)
 84             {
 85             System.out.println(list2.get(i).getName());
 86             parse(list2.get(i));
 87             }
 88             else
 89             {
 90                 System.out.println(list2.get(i).getName()+": "+list2.get(i).getText());
 91             }
 92             
 93             
 94             List<Attribute> list3 = list2.get(i).attributes();
 95             if(!list3.isEmpty())
 96             {
 97             for(Attribute attr:list3)
 98             {
 99                 System.out.println("属性："+attr.getName()+"="+attr.getText());
100             }
101             }
102 
103             
104         }
105         
106     }
107     
108 }

dom4j