在官网https://dom4j.github.io/下载最新的dom4j的jar包，以及配合xpath解析的http://central.maven.org/maven2/jaxen/jaxen/1.1.6/的jaxen.jar包。
总的来说其实要掌握的是，node和element和attribute的使用，以及一些迭代器配合。下面展示示例代码。具体演示了xml的增删改查的操作。
package Day04; import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.util.Iterator;
import java.util.List; import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import org.junit.Test; public class XmlDemo {
private void documentToFile(Document doucument,String charsetName) throws Exception {
FileOutputStream fileWiter = new FileOutputStream("src/book.xml");
OutputFormat format = OutputFormat.createPrettyPrint();
XMLWriter writer = new XMLWriter(new OutputStreamWriter(fileWiter,charsetName), format);
writer.write( doucument );
writer.close();
}
@Test
public void CreateXml() {
Document document = DocumentHelper.createDocument();
Element root = document.addElement("书店");
Element cateGrayElement1 = root.addElement("分类").addAttribute("descript", "童话故事");
Element cateGrayElement2 = root.addElement("分类").addAttribute("descript", "IT技术刊"); Element bookElement1 = cateGrayElement1.addElement("书");
bookElement1.addElement("书名").addText("格林童话");
bookElement1.addElement("国家").addText("非中");
Element bookElement2 = cateGrayElement1.addElement("书");
bookElement2.addElement("书名").addText("愚公移山");
bookElement2.addElement("国家").addText("中国");
Element bookElement3 = cateGrayElement2.addElement("书");
bookElement3.addElement("书名").addText("Tcp/ip 详解");
bookElement3.addElement("国家").addText("非中");
Element bookElement4 = cateGrayElement2.addElement("书");
bookElement4.addElement("书名").addText("c语言入门");
bookElement4.addElement("国家").addText("中国");
try {
documentToFile(document,"UTF-8");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void treeWalk(Document document) {
treeWalk(document.getRootElement());
} public void treeWalk(Element element) {
for (int i = 0, size = element.nodeCount(); i < size; i++) {
Node node = element.node(i);
if (node instanceof Element) {
String name = node.getName();
switch(name) {
case "分类":System.out.println(name+"(descript="+((Element) node).attributeValue("descript")+")");break;
case "书":System.out.println("\t"+name);break;
default:System.out.println("\t\t"+name+" "+node.getText());
}
treeWalk((Element) node);
}
else {
// do something…
}
}
}
/*
* 递归输出xml
*/
@Test
public void loopXml() throws Exception {
SAXReader reader = new SAXReader();
Document document = reader.read("src/book.xml");
treeWalk(document);
} /**
* 利用xpath语法 获取属性和节点
*/
@Test
public void xpath() throws Exception {
SAXReader reader = new SAXReader();
Document document = reader.read("src/book.xml");
System.out.println("----------------------获取属性---------------------------------");
List<Node> attrlists = document.selectNodes("//@descript");
Iterator<Node> attrIt = attrlists.iterator();
while(attrIt.hasNext()) {
Attribute attr = (Attribute)attrIt.next();
System.out.println("分类的"+(attr).getName()+"="+attr.getData());
}
System.out.println("----------------------获取节点---------------------------------");
List<Node> lists = document.selectNodes("//书");
Iterator<Node> it = lists.iterator();
while(it.hasNext()) {
//获取子类值
Node node = it.next();
for (Iterator<Element> bookIt = ((Element)node).elementIterator(); bookIt.hasNext();) {
Element element = bookIt.next();
System.out.println(element.getName()+":"+element.getText());
// do something
}
} System.out.println("-----------------------获取属性的节点--------------------------------");
List<Node> attrlists1 = document.selectNodes("//分类[@descript=\"童话故事\"]");
Iterator<Node> attrIt1 = attrlists1.iterator();
while(attrIt1.hasNext()) {
//获取子类值
Element cateElement = (Element)attrIt1.next();
System.out.println(cateElement.getName()+"attributes:descript="+cateElement.attribute("descript").getValue());
}
} /**
* 演示插入,在愚公移山书名后加一个简介(指定位置插入)
*/
@Test
public void insert() throws Exception {
SAXReader reader = new SAXReader();
Document document = reader.read("src/book.xml");
//找到第二本书//分类[@descript="童话故事"]/书[2]
Node pNode = document.selectSingleNode("//分类[@descript=\"童话故事\"]/书[2]");
List<Element> list = ((Element)pNode).elements();
Element addNode = DocumentHelper.createElement("简介");
addNode.addText("《愚公移山》是战国时期思想家列子创作的一篇寓言小品文。文章叙述了愚公不畏艰难，坚持不懈，挖山不止，最终感动天帝而将山挪走的故事。");
list.add(1, addNode);
System.out.println(list.toArray());
try {
documentToFile(document,"UTF-8");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} /**
* 修改xml元素
*/
@Test
public void update() throws Exception {
SAXReader reader = new SAXReader();
Document document = reader.read("src/book.xml");
//找到要修改的节点，比如我现在想给愚公移山这个书名加上书名号
Node pNode = document.selectSingleNode("//分类[@descript=\"童话故事\"]/书[2]/书名");
pNode.setText(new StringBuffer().append("《").append(pNode.getText()).append("》").toString());
try {
documentToFile(document,"UTF-8");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} /**
* 删除，刚刚添加的愚公移山的简介
*/
@Test
public void delete() throws Exception {
SAXReader reader = new SAXReader();
Document document = reader.read("src/book.xml");
//找到要修改的节点，比如我现在想给愚公移山这个书名加上书名号
Node pNode = document.selectSingleNode("//分类[@descript=\"童话故事\"]/书[2]/简介");
((Element)pNode).getParent().remove(pNode);
try {
documentToFile(document,"UTF-8");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}