Dom4j 操作XML · JSON/XML 專欄

Dom4j也可以很方便完成XML文檔的創建、元素的修改、文檔的查詢遍歷等，但dom4j稍比jdom復雜一點，不過在大片文檔的情況下dom4j的性能要不jdom好。 ### 準備首先，提供相關的jar包 Dom4jjar包下載： [http://sourceforge.net/projects/dom4j/files/dom4j-2.0.0-ALPHA-2/](http://sourceforge.net/projects/dom4j/files/dom4j-2.0.0-ALPHA-2/) jaxenjar下載： [http://repo1.maven.org/maven2/jaxen/jaxen/1.1.1/jaxen-1.1.1.jar](http://repo1.maven.org/maven2/jaxen/jaxen/1.1.1/jaxen-1.1.1.jar) 和dom4j依賴或相關的jar： [http://dom4j.sourceforge.net/dependencies.html](http://dom4j.sourceforge.net/dependencies.html) Junit-jar下載： [http://ebr.springsource.com/repository/app/bundle/version/download?name=com.springsource.org.junit&version=4.8.1&type=binary](http://ebr.springsource.com/repository/app/bundle/version/download?name=com.springsource.org.junit&version=4.8.1&type=binary) ? 其次，準備測試案例的部分代碼： ~~~ 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 hoojo_@126.com * @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); } } ~~~ ### 創建一篇XML文檔文檔格式如下： ~~~ <?xml version="1.0" encoding="UTF-8"?> <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> ~~~ 創建文檔代碼如下： ~~~ /** * <b>function:</b>創建文檔 * @author hoojo * @createDate 2011-8-5 下午06:18:18 */ @Test public void createDocument() { //創建一篇文檔 Document doc = DocumentHelper.createDocument(); //添加一個元素 Element root = doc.addElement("catalog"); //為root元素添加注釋 root.addComment("An XML Catalog"); //添加標記 root.addProcessingInstruction("target", "instruction"); //創建元素 Element journalEl = new BaseElement("journal"); //添加屬性 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"); //設置文本內容 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() 方法添加文檔類型說明。 doc.addDocType("catalog", null,"file://c:/Dtds/catalog.dtd"); fail(doc.getRootElement().getName()); //將xml轉換成文本 fail(doc.asXML()); //寫入到文件 /*XMLWriter output; try { output = new XMLWriter(new FileWriter(new File("file/catalog.xml"))); output.write(doc); output.close(); } catch (IOException e) { e.printStackTrace(); }*/ } ~~~ DocumentHelper是一個文檔助手類（工具類），它可以完成文檔、元素、文本、屬性、注釋、CDATA、Namespace、XPath的創建，以及利用XPath完成文檔的遍歷和將文本轉換成Document； parseText完成將xml字符串轉換成Doc的功能 <table border="1" cellpadding="0" cellspacing="0"><tbody><tr><td valign="top"><p><span style="font-size:13px">Document doc = DocumentHelper.parseText("<root></root>");</span></p></td></tr></tbody></table> ? createDocument創建一個文檔 <table border="1" cellpadding="0" cellspacing="0" height="32" width="359"><tbody><tr><td valign="top"><p><span style="font-size:13px">Document doc = DocumentHelper.createDocument();</span></p></td></tr></tbody></table> 如果帶參數就會創建一個帶有根元素的文檔 createElement創建一個元素 <table border="1" cellpadding="0" cellspacing="0" height="32" width="357"><tbody><tr><td valign="top"><p><span style="font-size:13px">Element el = DocumentHelper.createElement("el");</span></p></td></tr></tbody></table> Document的addElement方法可以給當前文檔添加一個子元素 <table border="1" cellpadding="0" cellspacing="0" height="32" width="355"><tbody><tr><td valign="top"><p><span style="font-size:13px">Element root = doc.addElement("catalog");</span></p></td></tr></tbody></table> addComment方法可以添加一段注釋 <table border="1" cellpadding="0" cellspacing="0" height="32" width="351"><tbody><tr><td valign="top"><p><span style="font-size:13px">root.addComment("An XML Catalog");</span></p></td></tr></tbody></table> 為root元素添加一段注釋 addProcessingInstruction添加一個標記 <table border="1" cellpadding="0" cellspacing="0" height="32" width="348"><tbody><tr><td valign="top"><p><span style="font-size:13px">root.addProcessingInstruction("target", "instruction");</span></p></td></tr></tbody></table> 為root元素添加一個標記 newBaseElement可以創建一個元素 <table border="1" cellpadding="0" cellspacing="0" height="32" width="350"><tbody><tr><td valign="top"><p><span style="font-size:13px">Element journalEl = new BaseElement("journal");</span></p></td></tr></tbody></table> addAttribute添加屬性 <table border="1" cellpadding="0" cellspacing="0" height="32" width="350"><tbody><tr><td valign="top"><p><span style="font-size:13px">journalEl.addAttribute("title", "XML Zone");</span></p></td></tr></tbody></table> add添加一個元素 <table border="1" cellpadding="0" cellspacing="0" height="32" width="349"><tbody><tr><td valign="top"><p><span style="font-size:13px">root.add(journalEl);</span></p></td></tr></tbody></table> 將journalEl元素添加到root元素中 addElement添加一個元素，并返回當前元素 <table border="1" cellpadding="0" cellspacing="0" height="32" width="346"><tbody><tr><td valign="top"><p><span style="font-size:13px">Element articleEl = journalEl.addElement("article");</span></p></td></tr></tbody></table> 給journalEl元素添加一個子元素article setText、addText可以設置元素的文本 <table border="1" cellpadding="0" cellspacing="0" height="56" width="349"><tbody><tr><td valign="top"><p><span style="font-size:13px">authorEl.addElement("firstname").setText("Marcello");</span></p><p><span style="font-size:13px">authorEl.addElement("lastname").addText("Vitaletti");</span></p></td></tr></tbody></table> addDocType可以設置文檔的DOCTYPE <table border="1" cellpadding="0" cellspacing="0"><tbody><tr><td valign="top"><p><span style="font-size:13px">doc.addDocType("catalog", null,"file://c:/Dtds/catalog.dtd");</span></p></td></tr></tbody></table> asXML可以將文檔或元素轉換成一段xml字符串 <table border="1" cellpadding="0" cellspacing="0" height="56" width="344"><tbody><tr><td valign="top"><p><span style="font-size:13px">doc.asXML();</span></p><p><span style="font-size:13px">root.asXML();</span></p></td></tr></tbody></table> XMLWriter類可以把文檔寫入到文件中 <table border="1" cellpadding="0" cellspacing="0"><tbody><tr><td valign="top"><p><span style="font-size:13px">output = new XMLWriter(new FileWriter(new File("file/catalog.xml")));</span></p><p><span style="font-size:13px">output.write(doc);</span></p><p><span style="font-size:13px">output.close();</span></p></td></tr></tbody></table> ### 修改XML文檔內容 ~~~ /** * <b>function:</b> 修改XML內容 * @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")); //修改屬性內容 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())) { //修改屬性值 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())) { //修改屬性值 attr.setValue("December-2011"); fail(attr.getName() + "#" + attr.getValue() + "#" + attr.getText()); } } //修改節點內容 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()); } } } //修改節點子元素內容 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()); } } //寫入到文件 /*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"));讀取指定xml文件內容到文檔中； selectNodes是XPath的查詢方法，完成xml文檔的查詢，傳遞xpath路徑。其使用方法可以參考jdom的xpath的使用方法：[http://www.cnblogs.com/hoojo/archive/2011/08/11/2134638.html](http://www.cnblogs.com/hoojo/archive/2011/08/11/2134638.html) getName獲取元素標簽名稱、getValue、getText獲取值、文本內容； elementIterator("title");獲取當前節點下所有的title元素，返回Iterator； elements獲取下面所有的子元素，返回的是一個集合List； ### 顯示文檔相關信息 ~~~ private String format(int i) { String temp = ""; while (i > 0) { temp += "--"; i--; } return temp; } /** * <b>function:</b>遞歸顯示文檔內容 * @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>顯示文檔相關信息 * @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()); } ~~~ ### 刪除文檔內容 ~~~ /** * <b>function:</b> 刪除節點內容 * @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()")); //刪除注釋 doc.getRootElement().remove(doc.selectSingleNode("//comment()")); Element node = (Element) doc.selectSingleNode("//article"); //刪除屬性 node.remove(new DOMAttribute(QName.get("level"), "Introductory")); //刪除元素節點 node.remove(doc.selectSingleNode("//title")); //只能刪除下一級節點，不能超過一級；（需要在父元素的節點上刪除子元素） 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()")); //刪除text文本 //firstNameEl.remove(firstNameEl.selectSingleNode("text()")); //firstNameEl.remove(doc.selectSingleNode("//firstname/text()")); firstNameEl.remove(doc.selectSingleNode("//*[text()='Ayesha']/text()")); //刪除子元素author //node.remove(node.selectSingleNode("//author")); fail(doc.asXML()); } catch (Exception e) { e.printStackTrace(); } } ~~~ 刪除注釋 <table border="1" cellpadding="0" cellspacing="0"><tbody><tr><td valign="top"><p><span style="font-size:13px">doc.getRootElement().remove(doc.selectSingleNode("//comment()"));</span></p></td></tr></tbody></table> 刪除root元素下面的注釋刪除屬性 <table border="1" cellpadding="0" cellspacing="0"><tbody><tr><td valign="top"><p><span style="font-size:13px">node.remove(new DOMAttribute(QName.get("level"), "Introductory"));</span></p></td></tr></tbody></table> 刪除node節點中的名稱為level，其值為Introductory的屬性刪除元素 <table border="1" cellpadding="0" cellspacing="0" height="32" width="401"><tbody><tr><td valign="top"><p><span style="font-size:13px">node.remove(doc.selectSingleNode("//title"));</span></p></td></tr></tbody></table> 刪除node節點下的title元素刪除文本 <table border="1" cellpadding="0" cellspacing="0"><tbody><tr><td valign="top"><p><span style="font-size:13px">firstNameEl.remove(firstNameEl.selectSingleNode("text()"));</span></p><p><span style="font-size:13px">firstNameEl.remove(doc.selectSingleNode("//firstname/text()"));</span></p><p><span style="font-size:13px">firstNameEl.remove(doc.selectSingleNode("//*[text()='Ayesha']/text()"));</span></p></td></tr></tbody></table> 刪除firstNameEl的文本內容