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Attribute 定义了 XML 的属性 |
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Branch 为能够包含子节点的节点如 XML 元素 (Element) 和文档 (Docuemnts) 定义了一个公共的行为, |
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CDATA 定义了XML CDATA 区域 |
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CharacterData 是一个标识借口,标识基于字符的节点。如 CDATA , Comment, Text . |
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Comment 定义了XML注释的行为 |
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定义了 XML文档 |
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DocumentType 定义XML DOCTYPE声明 |
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Element 定义XML 元素 |
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ElementHandler 定义了 Element 对象的处理器 |
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Entity 定义 XML entity |
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Node 为所有的 dom4j 中 XML 节点 定义了多态行为 |
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NodeFilter 定义了在dom4j节点中产生的一个滤镜或谓词的行为(predicate) |
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ProcessingInstruction 定义 XML 处理指令. |
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Text 定义XML 文本节点. |
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Visitor 用于实现Visitor 模式. |
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XPath 在分析一个字符串后会提供一个XPath 表达式 |
- interface java.lang.Cloneable
- interface org.dom4j.
- interface org.dom4j.CharacterData
- interface org.dom4j.
// 从文件读取XML,输入文件名,返回XML文档
public Document read(String fileName) throws MalformedURLException, DocumentException {
SAXReader reader = new SAXReader();
Document document = reader.read(new File(fileName));
return document;
}
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public Element getRootElement(Document doc){
return doc.getRootElement();
}
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// 枚举所有子节点
for ( Iterator i = root.elementIterator(); i.hasNext(); ) {
Element element = (Element) i.next();
// do something
}
// 枚举名称为foo的节点
for ( Iterator i = root.elementIterator(foo); i.hasNext();) {
Element foo = (Element) i.next();
// do something
}
// 枚举属性
for ( Iterator i = root.attributeIterator(); i.hasNext(); ) {
Attribute attribute = (Attribute) i.next();
// do something
}
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public void treeWalk() {
treeWalk(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) {
treeWalk((Element) node);
} else { // do something....
}
}
}
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public class MyVisitor extends VisitorSupport {
public void visit(Element element){
System.out.println(element.getName());
}
public void visit(Attribute attr){
System.out.println(attr.getName());
}
} 调用: root.accept(new MyVisitor()) |
public void bar(Document document) {
List list = document.selectNodes( //foo/bar );
Node node = document.selectSingleNode(//foo/bar/author);
String name = node.valueOf( @name );
}
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public void findLinks(Document document) throws DocumentException {
List list = document.selectNodes( //a/@href );
for (Iterator iter = list.iterator(); iter.hasNext(); ) {
Attribute attribute = (Attribute) iter.next();
String url = attribute.getValue();
}
}
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// XML转字符串 Document document = ...;
String text = document.asXML();
// 字符串转XML
String text = <person> <name>James</name> </person>;
Document document = DocumentHelper.parseText(text);
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public Document styleDocument(
Document document,
String stylesheet
) throws Exception {
// load the transformer using JAXP
TransformerFactory factory = TransformerFactory.newInstance();
Transformer transformer = factory.newTransformer(
new StreamSource( stylesheet )
);
// now lets style the given document
DocumentSource source = new DocumentSource( document );
DocumentResult result = new DocumentResult();
transformer.transform( source, result );
// return the transformed document
Document transformedDoc = result.getDocument();
return transformedDoc;
}
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public Document createDocument() {
Document document = DocumentHelper.createDocument();
Element root = document.addElement(root);
Element author1 =
root
.addElement(author)
.addAttribute(name, James)
.addAttribute(location, UK)
.addText(James Strachan);
Element author2 =
root
.addElement(author)
.addAttribute(name, Bob)
.addAttribute(location, US)
.addText(Bob McWhirter);
return document;
}
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FileWriter out = new FileWriter( foo.xml );
document.write(out);
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如果你想改变输出的格式,比如美化输出或缩减格式,可以用XMLWriter类
public void write(Document document) throws IOException {
// 指定文件
XMLWriter writer = new XMLWriter(
new FileWriter( output.xml )
);
writer.write( document );
writer.close();
// 美化格式
OutputFormat format = OutputFormat.createPrettyPrint();
writer = new XMLWriter( System.out, format );
writer.write( document );
// 缩减格式
format = OutputFormat.createCompactFormat();
writer = new XMLWriter( System.out, format );
writer.write( document );
}
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