Dom4j下载及使用Dom4j读写XML简介
要使用dom4j读写XML文档,需要先下载dom4j包,dom4j官方网站在 http://www.dom4j.org/
目前最新dom4j包下载地址:http://nchc.dl.sourceforge.net/sourceforge/dom4j/dom4j-1.6.1.zip
解开后有两个包,仅操作XML文档的话把dom4j-1.6.1.jar加入工程就可以了,如果需要使用XPath的话还需要加入包jaxen-1.1-beta-7.jar.
以下是相关操作:
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
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();
六.使用XPath快速找到节点.
读取的XML文档示例
<?xml version="1.0" encoding="UTF-8"?>
<projectDescription>
? <name>MemberManagement</name>
? <comment></comment>
? <projects>
??? <project>PRJ1</project>
??? <project>PRJ2</project>
??? <project>PRJ3</project>
??? <project>PRJ4</project>
? </projects>
? <buildSpec>
??? <buildCommand>
????? <name>org.eclipse.jdt.core.javabuilder</name>
????? <arguments>
????? </arguments>
??? </buildCommand>
? </buildSpec>
? <natures>
??? <nature>org.eclipse.jdt.core.javanature</nature>
? </natures>
</projectDescription>
使用XPath快速找到节点project.
?public static void main(String[] args){
??? SAXReader reader = new SAXReader();
???
??? try{
????? Document? doc = reader.read(new File("sample.xml"));
?????
????? List projects=doc.selectNodes("/projectDescription/projects/project");
?????
????? Iterator it=projects.iterator();
?????
????? while(it.hasNext()){
??????? Element elm=(Element)it.next();??????
??????? System.out.println(elm.getText());
????? }
?????
??? }
??? catch(Exception ex){
?????? ex.printStackTrace();
??? }
? }
