DOM4J解析

这是一个简单的DOM4J解析

public class demo0000 {
	public static void main(String[] args) throws Exception{
		 XMLWriter writer = null;
         SAXReader reader = new SAXReader();
         
         OutputFormat format = OutputFormat.createPrettyPrint();
         format.setEncoding("GBK");

         String filePath = "d:\\student.xml";
         File file = new File(filePath);

         boolean bl=false;
       
         if (file.exists()) {
        	 Document document = reader.read(file);
             Element root = document.getRootElement();
             for (Iterator i = root.elementIterator("学生"); i.hasNext();) {
                 Element student = (Element) i.next();
          
                 if (student.element("编号").equals("007")) {
                	 student.element("姓名").setText("shdka");
                     student.element("年龄").setText("22");
               
                     writer = new XMLWriter(new FileWriter(filePath), format);
                     writer.write(document);
                     writer.close();
                     bl=true;
                     break;}
                 }
               if (bl) {
                	 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("美女");
                	 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 {
                 Document doc = DocumentHelper.createDocument();
                 Element ro = doc.addElement("学生信息");
                 Element stu = ro.addElement("学生");
                 stu.addAttribute("sid", "001");
                 Element id = stu.addElement("编号");
                 id.setText("007");
                 Element name = stu.addElement("姓名");
                 name.setText("沧海");
                 Element age = stu.addElement("年龄");
                 age.setText("18");

                 writer = new XMLWriter(new FileOutputStream(new File("D://student.xml")), format);
                 writer.write(doc);
                 writer.close();
             }       
             
	}
}

以下是DOM4J操作
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();