dom4j使用小结(基础入门级)
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本文从以下几个基础的方面介绍dom4j操作XML的使用小结：
[一] 读取XML文件的示例[二] 读取XML字符串的示例[三] 解析XML的document的示例[四] XML编码格式转换的示例[五] 输出格式的自定义的示例?
[一]、读取XML文件：
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xml示例的文件d:/test/michael/dom4j_info.xml，内容如下：
<?xml version="1.0" encoding="UTF-8"?><root><info index="1" type="blog"><URL>http://sjsky.iteye.com</URL><name id="sjsky">Michael</name><categories><category valule="java"/><category valule="spring"/><category valule="hibernate"/><category valule="NoSQL"/><category valule="MYSQL"/></categories></info></root>
?读取文件的Java代码如下：
String fileName = "d:/test/michael/dom4j_info.xml";try { SAXReader reader = new SAXReader(); Document document = reader.read(new File(fileName)); System.out.println("document转化为String输出如下："); System.out.println(document.asXML()); } catch (Exception e) { e.printStackTrace(); }?
document转化为String输出如下：<?xml version="1.0" encoding="UTF-8"?><root><info index="1" type="blog"><URL>http://sjsky.iteye.com</URL><name id="sjsky">Michael</name><categories><category valule="java"/><category valule="spring"/><category valule="hibernate"/><category valule="NoSQL"/><category valule="MYSQL"/></categories></info></root>
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ps：一般默认以XML文件中encoding定义的编码格式读取文件。
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[二]、读取XML字符串：
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Java读取String的demo代码：
System.out.println("解析XML字符串DEMO"); String xmlStr = "<root><info index="1" type="blog">" + "<URL>http://sjsky.iteye.com</URL>" + "<name id="sjsky">Michael</name>" + "<categories><category valule="java"/>" + "<category valule="spring"/><category valule="hibernate"/>" + "<category valule="NoSQL"/><category valule="MYSQL"/>" + "</categories></info></root>"; try { Document document = DocumentHelper.parseText(xmlStr); System.out.println("document信息输出,默认为UTF-8的编码："); System.out.println(document.asXML()); } catch (Exception e) { e.printStackTrace(); }<root><info index="1" type="blog"><URL>http://sjsky.iteye.com</URL><name id="sjsky">Michael</name><categories><category valule="java"/><category valule="spring"/><category valule="hibernate"/><category valule="NoSQL"/><category valule="MYSQL"/></categories></info></root>ps：1.默认输出编码为UTF-8
? ? ? 2.输出字符串格式定义参见本文 第[五]部分?
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[三]、解析XML的Document
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/** * 解析文件 * @blog http://sjsky.iteye.com * @param fileName */ public static void readXMLFile(String fileName) { try { SAXReader reader = new SAXReader(); Document document = reader.read(new File(fileName)); readXML(document); } catch (Exception e) { e.printStackTrace(); } } public static void readXML(Document document) { try { System.out.println("开始解析 XML Document："); // 获取跟节点 Element rootEle = document.getRootElement(); System.out.println("获取跟节点Root:"); System.out.println(rootEle.asXML()); // 根据名称获取Element Element info = rootEle.element("info"); System.out.println("获取Root下名称为info的子Element："); System.out.println(info.asXML()); // 根据名称获取List<Element> List<Element> infolist = rootEle.elements("info"); System.out.println("和上面获取的Element应该一致："); System.out.println(infolist.get(0).asXML()); // 获取属性值 System.out.println("获取指定属性type的值 = " + info.attributeValue("type")); // 获取所有的属性值 for (int i = 0; i < info.attributeCount(); i++) { System.out.println("获取所有的属性和值: " + info.attribute(i).getName() + " = " + info.attribute(i).getValue()); } // XPath的功能展示 Node node1 = document.selectSingleNode("/root/info/name"); System.out.println("根据XPath=/root/info/name获取document下的ELement ： " + node1.asXML()); Node node2 = rootEle.selectSingleNode("info/name"); System.out.println("根据XPath=info/name 获取root下的ELement ： " + node2.asXML()); Node node3 = rootEle.selectSingleNode("//info/name"); System.out.println("根据XPath=//info/name 获取root下的ELement ： " + node3.asXML()); System.out.println("上述三种方式获取的结果应该是一致"); List<?> nodeList = rootEle .selectNodes("//info/categories/category"); System.out .println("根据XPath=//info/categories/category获取root下的List:"); for (int i = 0; i < nodeList.size(); i++) { System.out.println(((Element) nodeList.get(i)).asXML()); } } catch (Exception e) { e.printStackTrace(); } }??开始解析 XML Document：获取跟节点Root:<root><info index="1" type="blog"><URL>http://sjsky.iteye.com</URL><name id="sjsky">Michael</name><categories><category valule="java"/><category valule="spring"/><category valule="hibernate"/><category valule="NoSQL"/><category valule="MYSQL"/></categories></info></root>获取Root下名称为info的子Element：<info index="1" type="blog"><URL>http://sjsky.iteye.com</URL><name id="sjsky">Michael</name><categories><category valule="java"/><category valule="spring"/><category valule="hibernate"/><category valule="NoSQL"/><category valule="MYSQL"/></categories></info>和上面获取的Element应该一致：<info index="1" type="blog"><URL>http://sjsky.iteye.com</URL><name id="sjsky">Michael</name><categories><category valule="java"/><category valule="spring"/><category valule="hibernate"/><category valule="NoSQL"/><category valule="MYSQL"/></categories></info>获取指定属性type的值 = blog获取所有的属性和值: index = 1获取所有的属性和值: type = blog根据XPath=/root/info/name获取document下的ELement ： <name id="sjsky">Michael</name>根据XPath=info/name 获取root下的ELement ： <name id="sjsky">Michael</name>根据XPath=//info/name 获取root下的ELement ： <name id="sjsky">Michael</name>上述三种方式获取的结果应该是一致根据XPath=//info/categories/category获取root下的List:<category valule="java"/><category valule="spring"/><category valule="hibernate"/><category valule="NoSQL"/><category valule="MYSQL"/>
ps：1. XPath的使用依赖lib包：jaxen.jar
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?nodename 选取此节点的所有子节点（相对路径）/ 从根节点选取（绝对路径） ????????// 从匹配选择的当前节点选择文档中的节点，而不考虑它们的位置.? 选取当前节点.. 选取当前节点的父节点@? 选取属性?
[四]、XML编码格式转换：
/** * @blog http://sjsky.iteye.com * @param args */ public static void main(String[] args) { String xmlStr = "<root><info index="1" type="blog">" + "<URL>http://sjsky.iteye.com</URL>" + "<name id="sjsky">Michael</name>" + "<categories><category valule="java"/>" + "<category valule="spring"/><category valule="hibernate"/>" + "<category valule="NoSQL"/><category valule="MYSQL"/>" + "</categories></info></root>"; System.out.println("XML编码转化DEMO"); try { Document document = DocumentHelper.parseText(xmlStr); System.out.println("默认为UTF-8的编码,输出内容如下："); System.out.println(document.asXML()); System.out.println("编码转化为gb2312后,输出内容如下："); String encodeStr = encodeXml(xmlStr, "gb2312"); System.out.println(encodeStr); } catch (Exception e) { e.printStackTrace(); } System.out.println("DEMO End---------------------"); }?
XML编码转化DEMO默认为UTF-8的编码,输出内容如下：<?xml version="1.0" encoding="UTF-8"?><root><info index="1" type="blog"><URL>http://sjsky.iteye.com</URL><name id="sjsky">Michael</name><categories><category valule="java"/><category valule="spring"/><category valule="hibernate"/><category valule="NoSQL"/><category valule="MYSQL"/></categories></info></root>编码转化为gb2312后,输出内容如下：<?xml version="1.0" encoding="gb2312"?><root> <info index="1" type="blog"> <URL>http://sjsky.iteye.com</URL> <name id="sjsky">Michael</name> <categories> <category valule="java"/> <category valule="spring"/> <category valule="hibernate"/> <category valule="NoSQL"/> <category valule="MYSQL"/> </categories> </info></root>DEMO End---------------------
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[五]、XML输出格式的定义：
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OutputFormat compactFormat = OutputFormat.createCompactFormat(); 紧凑的格式?
/** * @blog http://sjsky.iteye.com * @param args */ public static void main(String[] args) { String xmlStr = "<root><info index="1" type="blog">" + "<URL>http://sjsky.iteye.com</URL>" + "<name id="sjsky">Michael</name>" + "<categories><category valule="java"/>" + "<category valule="spring"/><category valule="hibernate"/>" + "<category valule="NoSQL"/><category valule="MYSQL"/>" + "</categories></info></root>"; System.out.println("XML输出格式定义Demo："); try { Document document = DocumentHelper.parseText(xmlStr); System.out.println("转换为优雅层次的格式输出："); OutputFormat prettyFormat = OutputFormat.createPrettyPrint(); String xmlPretty = xmlOutputFormat(document, prettyFormat); System.out.println(xmlPretty); System.out.println("转换为紧凑格式输出："); OutputFormat compactFormat = OutputFormat.createCompactFormat(); String xmlCompact = xmlOutputFormat(document, compactFormat); System.out.println(xmlCompact); } catch (Exception e) { e.printStackTrace(); } System.out.println("DEMO End---------------------"); } /** * XML 输出格式转换 * @param document * @param opFormat * @return String */ public static String xmlOutputFormat(Document document, OutputFormat opFormat) { // 具有层次的格式输出 // OutputFormat format = OutputFormat.createPrettyPrint(); // 紧凑的格式输出 // OutputFormat format = OutputFormat.createCompactFormat(); StringWriter sw = new StringWriter(); try { XMLWriter writer = new XMLWriter(opFormat); writer.setWriter(sw); writer.write(document); } catch (Exception e) { e.printStackTrace(); } return sw.toString(); }?
XML输出格式定义Demo：转换为优雅层次的格式输出：<?xml version="1.0" encoding="UTF-8"?><root> <info index="1" type="blog"> <URL>http://sjsky.iteye.com</URL> <name id="sjsky">Michael</name> <categories> <category valule="java"/> <category valule="spring"/> <category valule="hibernate"/> <category valule="NoSQL"/> <category valule="MYSQL"/> </categories> </info></root>转换为紧凑格式输出：<?xml version="1.0" encoding="UTF-8"?><root><info index="1" type="blog"><URL>http://sjsky.iteye.com</URL><name id="sjsky">Michael</name><categories><category valule="java"/><category valule="spring"/><category valule="hibernate"/><category valule="NoSQL"/><category valule="MYSQL"/></categories></info></root>DEMO End---------------------
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[六]、XML输出文件：
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/** * @blog http://sjsky.iteye.com * @author Michael * @param args */ public static void main(String[] args) { String xmlStr = "<root><info index="1" type="blog">" + "<URL>http://sjsky.iteye.com</URL>" + "<name id="sjsky">Michael</name>" + "<categories><category valule="java"/>" + "<category valule="spring"/><category valule="hibernate"/>" + "<category valule="NoSQL"/><category valule="MYSQL"/>" + "</categories></info></root>"; System.out.println("XML输出文件："); String outFileName = "d:/test/michael/"; try { Document document = DocumentHelper.parseText(xmlStr); xmlWriteXMLDoc(outFileName+"dom4j_info_out1.xml", document); fileWriteXMLDoc(outFileName+"dom4j_info_out2.xml", document); } catch (Exception e) { e.printStackTrace(); } System.out.println("DEMO End---------------------"); } /** * * @param fileName * @param document */ public static void xmlWriteXMLDoc(String fileName, Document document) { XMLWriter writer = null; try { //writer = new XMLWriter(new FileWriter(fileName)); //writer = new XMLWriter(new FileWriter(fileName),OutputFormat.createCompactFormat()); writer = new XMLWriter(new FileWriter(fileName),OutputFormat.createPrettyPrint()); writer.write(document); } catch (Exception e) { e.printStackTrace(); } finally { try { if (null != writer) { writer.close(); } } catch (Exception e) { e.printStackTrace(); } } } /** * * @param fileName * @param document */ public static void fileWriteXMLDoc(String fileName, Document document) { FileWriter fw = null; try { fw = new FileWriter(fileName); document.write(fw); } catch (Exception e) { e.printStackTrace(); } finally { try { if (null != fw) { fw.close(); } } catch (Exception e) { e.printStackTrace(); } } }?
生成的dom4j_info_out1.xml文件内容如下：
<?xml version="1.0" encoding="UTF-8"?><root> <info index="1" type="blog"> <URL>http://sjsky.iteye.com</URL> <name id="sjsky">Michael</name> <categories> <category valule="java"/> <category valule="spring"/> <category valule="hibernate"/> <category valule="NoSQL"/> <category valule="MYSQL"/> </categories> </info></root>
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生成的dom4j_info_out2.xml文件内容如下：
<?xml version="1.0" encoding="UTF-8"?><root><info index="1" type="blog"><URL>http://sjsky.iteye.com</URL><name id="sjsky">Michael</name><categories><category valule="java"/><category valule="spring"/><category valule="hibernate"/><category valule="NoSQL"/><category valule="MYSQL"/></categories></info></root>
到此有关dom4j的简单应用基本介绍完了，希望给新接触的tx有所帮助。
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