Dom4j 操作XML
Dom4j也可以很方便完成XML文档的创建、元素的修改、文档的查询遍历等，但dom4j稍比jdom复杂一点，不过在大片文档的情况下dom4j的性能要不jdom好。
# 准备
首先，提供相关的jar包
Dom4jjar包下载：
http://sourceforge.net/projects/dom4j/files/dom4j-2.0.0-ALPHA-2/
jaxenjar下载：
http://repo1.maven.org/maven2/jaxen/jaxen/1.1.1/jaxen-1.1.1.jar
和dom4j依赖或相关的jar：
http://dom4j.sourceforge.net/dependencies.html
Junit-jar下载：
http://ebr.springsource.com/repository/app/bundle/version/download?name=com.springsource.org.junit&version=4.8.1&type=binary
其次，准备测试案例的部分代码：
package com.hoo.test; import java.io.File; import java.util.Iterator; import java.util.List; import org.dom4j.Attribute; import org.dom4j.Document; import org.dom4j.DocumentException; import org.dom4j.DocumentHelper; import org.dom4j.Element; import org.dom4j.Node; import org.dom4j.QName; import org.dom4j.dom.DOMAttribute; import org.dom4j.io.SAXReader; import org.dom4j.tree.BaseElement; import org.junit.After; import org.junit.Before; import org.junit.Test; /** * <b>function:</b> 使用Dom4j操作XML * @author hoojo * @createDate 2011-8-5 下午06:15:40 * @file DocumentTest.java * @package com.hoo.test * @project Dom4jTest * @blog http://blog.csdn.net/IBM_hoojo * @email [email protected] * @version 1.0 */ public class DocumentTest { private SAXReader reader = null; @Before public void init() { reader = new SAXReader(); } @After public void destory() { reader = null; System.gc(); } public void fail(Object o) { if (o != null) System.out.println(o); } }
# 创建一篇XML文档
文档格式如下：
<?xml version="1.0" encoding="UTF-8"?> <catalog> <!--An XML Catalog--> <?target instruction?> <journal title="XML Zone" publisher="IBM developerWorks"> <article level="Intermediate" date="December-2001"> <title>Java configuration with XML Schema</title> <author> <firstname>Marcello</firstname> <lastname>Vitaletti</lastname> </author> </article> </journal> </catalog>
创建文档代码如下：
/**
* <b>function:</b>创建文档
* @author hoojo
* @createDate 2011-8-5 下午06:18:18
*/
@Test
public void createDocument() {
//创建一篇文档
Document doc = DocumentHelper.createDocument();
//添加一个元素
Element root = doc.addElement("catalog");
//为root元素添加注释
root.addComment("An XML Catalog");
//添加标记
root.addProcessingInstruction("target", "instruction");
//创建元素
Element journalEl = new BaseElement("journal");
//添加属性
journalEl.addAttribute("title", "XML Zone");
journalEl.addAttribute("publisher", "IBM developerWorks");
root.add(journalEl);
//添加元素
Element articleEl = journalEl.addElement("article");
articleEl.addAttribute("level", "Intermediate");
articleEl.addAttribute("date", "December-2001");
Element titleEl = articleEl.addElement("title");
//设置文本内容
titleEl.setText("Java configuration with XML Schema");
//titleEl.addText("Java configuration with XML Schema");
Element authorEl = articleEl.addElement("author");
authorEl.addElement("firstname").setText("Marcello");
authorEl.addElement("lastname").addText("Vitaletti");
//可以使用 addDocType() 方法添加文档类型说明。
doc.addDocType("catalog", null,"file://c:/Dtds/catalog.dtd");
fail(doc.getRootElement().getName());
//将xml转换成文本
fail(doc.asXML());
//写入到文件
/*XMLWriter output;
try {
output = new XMLWriter(new FileWriter(new File("file/catalog.xml")));
output.write(doc);
output.close();
} catch (IOException e) {
e.printStackTrace();
}*/
}
* DocumentHelper是一个文档助手类（工具类），它可以完成文档、元素、文本、属性、注释、CDATA、Namespace、XPath的创建，以及利用XPath完成文档的遍历和将文本转换成Document；
parseText完成将xml字符串转换成Doc的功能
| Document doc = DocumentHelper.parseText("<root></root>"); |
createDocument创建一个文档
| Document doc = DocumentHelper.createDocument(); |
如果带参数就会创建一个带有根元素的文档
createElement创建一个元素
| Element el = DocumentHelper.createElement("el"); |
* Document的addElement方法可以给当前文档添加一个子元素
| Element root = doc.addElement("catalog"); |
* addComment方法可以添加一段注释
| root.addComment("An XML Catalog"); |
为root元素添加一段注释
* addProcessingInstruction添加一个标记
| root.addProcessingInstruction("target", "instruction"); |
为root元素添加一个标记
* newBaseElement可以创建一个元素
| Element journalEl = new BaseElement("journal"); |
* addAttribute添加属性
| journalEl.addAttribute("title", "XML Zone"); |
* add添加一个元素
| root.add(journalEl); |
将journalEl元素添加到root元素中
* addElement添加一个元素，并返回当前元素
| Element articleEl = journalEl.addElement("article"); |
给journalEl元素添加一个子元素article
* setText、addText可以设置元素的文本
| authorEl.addElement("firstname").setText("Marcello"); authorEl.addElement("lastname").addText("Vitaletti"); |
* addDocType可以设置文档的DOCTYPE
| doc.addDocType("catalog", null,"file://c:/Dtds/catalog.dtd"); |
* asXML可以将文档或元素转换成一段xml字符串
| doc.asXML(); root.asXML(); |
* XMLWriter类可以把文档写入到文件中
| output = new XMLWriter(new FileWriter(new File("file/catalog.xml"))); output.write(doc); output.close(); |
# 修改XML文档内容
/**
* <b>function:</b> 修改XML内容
* @author hoojo
* @createDate 2011-8-9 下午03:37:04
*/
@SuppressWarnings("unchecked")
@Test
public void modifyDoc() {
try {
Document doc = reader.read(new File("file/catalog.xml"));
//修改属性内容
List list = doc.selectNodes("//article/@level");
Iterator<Attribute> iter = list.iterator();
while (iter.hasNext()) {
Attribute attr = iter.next();
fail(attr.getName() + "#" + attr.getValue() + "#" + attr.getText());
if ("Intermediate".equals(attr.getValue())) {
//修改属性值
attr.setValue("Introductory");
fail(attr.getName() + "#" + attr.getValue() + "#" + attr.getText());
}
}
list = doc.selectNodes("//article/@date");
iter = list.iterator();
while (iter.hasNext()) {
Attribute attr = iter.next();
fail(attr.getName() + "#" + attr.getValue() + "#" + attr.getText());
if ("December-2001".equals(attr.getValue())) {
//修改属性值
attr.setValue("December-2011");
fail(attr.getName() + "#" + attr.getValue() + "#" + attr.getText());
}
}
//修改节点内容
list = doc.selectNodes("//article");
Iterator<Element> it = list.iterator();
while (it.hasNext()) {
Element el = it.next();
fail(el.getName() + "#" + el.getText() + "#" + el.getStringValue());
//修改title元素
Iterator<Element> elIter = el.elementIterator("title");
while(elIter.hasNext()) {
Element titleEl = elIter.next();
fail(titleEl.getName() + "#" + titleEl.getText() + "#" + titleEl.getStringValue());
if ("Java configuration with XML Schema".equals(titleEl.getTextTrim())) {
//修改元素文本值
titleEl.setText("Modify the Java configuration with XML Schema");
fail(titleEl.getName() + "#" + titleEl.getText() + "#" + titleEl.getStringValue());
}
}
}
//修改节点子元素内容
list = doc.selectNodes("//article/author");
it = list.iterator();
while (it.hasNext()) {
Element el = it.next();
fail(el.getName() + "#" + el.getText() + "#" + el.getStringValue());
List<Element> childs = el.elements();
for (Element e : childs) {
fail(e.getName() + "#" + e.getText() + "#" + e.getStringValue());
if ("Marcello".equals(e.getTextTrim())) {
e.setText("Ayesha");
} else if ("Vitaletti".equals(e.getTextTrim())) {
e.setText("Malik");
}
fail(e.getName() + "#" + e.getText() + "#" + e.getStringValue());
}
}
//写入到文件
/*XMLWriter output = new XMLWriter(new FileWriter(new File("file/catalog-modified.xml")));
output.write(doc);
output.close();*/
} catch (DocumentException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
* reader.read(new File("file/catalog.xml"));读取指定xml文件内容到文档中；
* selectNodes是XPath的查询方法，完成xml文档的查询，传递xpath路径。其使用方法可以参考jdom的xpath的使用方法：http://www.cnblogs.com/hoojo/archive/2011/08/11/2134638.html
* getName获取元素标签名称、getValue、getText获取值、文本内容；
* elementIterator("title");获取当前节点下所有的title元素，返回Iterator；
* elements获取下面所有的子元素，返回的是一个集合List；
# 显示文档相关信息
private String format(int i) {
String temp = "";
while (i > 0) {
temp += "--";
i--;
}
return temp;
}
/**
* <b>function:</b>递归显示文档内容
* @author hoojo
* @createDate 2011-8-9 下午03:43:45
* @param i
* @param els
*/
private void print(int i, List<Element> els) {
i++;
for (Element el : els) {
fail(format(i) + "##" + el.getName() + "#" + el.getTextTrim());
if (el.hasContent()) {
print(i, el.elements());
}
}
}
/**
* <b>function:</b>显示文档相关信息
* @author hoojo
* @createDate 2011-8-9 下午03:44:10
*/
@Test
public void printInfo() {
try {
Document doc = reader.read(new File("file/catalog.xml"));
fail("asXML: " + doc.asXML());
fail(doc.asXPathResult(new BaseElement("article")));
List<Node> list = doc.content();
for (Node node : list) {
fail("Node: " + node.getName() + "#" + node.getText() + "#" + node.getStringValue());
}
fail("-----------------------------");
print(0, doc.getRootElement().elements());
fail("getDocType: " + doc.getDocType());
fail("getNodeTypeName: " + doc.getNodeTypeName());
fail("getPath: " + doc.getRootElement().getPath());
fail("getPath: " + doc.getRootElement().getPath(new BaseElement("journal")));
fail("getUniquePath: " + doc.getRootElement().getUniquePath());
fail("getXMLEncoding: " + doc.getXMLEncoding());
fail("hasContent: " + doc.hasContent());
fail("isReadOnly: " + doc.isReadOnly());
fail("nodeCount: " + doc.nodeCount());
fail("supportsParent: " + doc.supportsParent());
} catch (DocumentException e) {
e.printStackTrace();
}
fail("getEncoding: " + reader.getEncoding());
fail("isIgnoreComments: " + reader.isIgnoreComments());
fail("isMergeAdjacentText: " + reader.isMergeAdjacentText());
fail("isStringInternEnabled: " + reader.isStringInternEnabled());
fail("isStripWhitespaceText: " + reader.isStripWhitespaceText());
fail("isValidating: " + reader.isValidating());
}
# 删除文档内容
/**
* <b>function:</b> 删除节点内容
* @author hoojo
* @createDate 2011-8-9 下午03:47:44
*/
@Test
public void removeNode() {
try {
Document doc = reader.read(new File("file/catalog-modified.xml"));
fail("comment: " + doc.selectSingleNode("//comment()"));
//删除注释
doc.getRootElement().remove(doc.selectSingleNode("//comment()"));
Element node = (Element) doc.selectSingleNode("//article");
//删除属性
node.remove(new DOMAttribute(QName.get("level"), "Introductory"));
//删除元素 节点
node.remove(doc.selectSingleNode("//title"));
//只能删除下一级节点，不能超过一级；（需要在父元素的节点上删除子元素）
Node lastNameNode = node.selectSingleNode("//lastname");
lastNameNode.getParent().remove(lastNameNode);
fail("Text: " + doc.selectObject("//*[text()='Ayesha']"));
Element firstNameEl = (Element)doc.selectObject("//firstname");
fail("Text: " + firstNameEl.selectSingleNode("text()"));
//删除text文本
//firstNameEl.remove(firstNameEl.selectSingleNode("text()"));
//firstNameEl.remove(doc.selectSingleNode("//firstname/text()"));
firstNameEl.remove(doc.selectSingleNode("//*[text()='Ayesha']/text()"));
//删除子元素author
//node.remove(node.selectSingleNode("//author"));
fail(doc.asXML());
} catch (Exception e) {
e.printStackTrace();
}
}
* 删除注释
| doc.getRootElement().remove(doc.selectSingleNode("//comment()")); |
删除root元素下面的注释
* 删除属性
| node.remove(new DOMAttribute(QName.get("level"), "Introductory")); |
删除node节点中的名称为level，其值为Introductory的属性
* 删除元素
| node.remove(doc.selectSingleNode("//title")); |
删除node节点下的title元素
* 删除文本
| firstNameEl.remove(firstNameEl.selectSingleNode("text()")); firstNameEl.remove(doc.selectSingleNode("//firstname/text()")); firstNameEl.remove(doc.selectSingleNode("//*[text()='Ayesha']/text()")); |
删除firstNameEl的文本内容