dom4j 资料读写相关方法

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();











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();
??????? }

??? }
}



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);
??????? }
??? }