dom4j读写xml文件

最新推荐文章于 2025-04-04 21:52:48 发布

转载最新推荐文章于 2025-04-04 21:52:48 发布 · 829 阅读

文章标签：

#xml #string #文档 #file #null

JAVA 同时被 2 个专栏收录

42 篇文章

订阅专栏

XML

6 篇文章

订阅专栏

首先我们给出一段示例程序：

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: