web开发总结----xml的写入、读取---2

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(
"");
                    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:

web开发总结----xml的写入、读取---2

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();

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